# is it possible 925 sterling silver powder



## capitano9VII (Feb 7, 2022)

Hello everybody. I have a question and I hope one of you guys can help me. I need to make 925 sterling silver powder. I tried this with silver-copper alloy. The copper in it melted because of the acid. The product I got was 999. I need 925. What can I do about it? silver-copper powder must be homogeneous.


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## Martijn (Feb 7, 2022)

Welcome to the forum. 
What do you mean melted because of the acid? What kind of acid? 

The only way I can come up with is filing sterling with a new fine file to get fine powder without contamination of sand paper or a dirty file. 
Cemented silver will be nearly pure.


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## capitano9VII (Feb 7, 2022)

Martijn said:


> Welcome to the forum.
> What do you mean melted because of the acid? What kind of acid?
> 
> The only way I can come up with is filing sterling with a new fine file to get fine powder without contamination of sand paper or a dirty file.
> Cemented silver will be nearly pure.


When we react with nitric acid, they both separate. when we add salt later, the silver precipitates and separates from the copper. my customer wants 925 silver powder. I thought of your method. but when we try this, the sandpaper and the iron from the file mix.


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## Martijn (Feb 7, 2022)

With iron from a file, which in my opinion should not happen due to the softness of silver, you could use magnetic separation on the powder. 
Sandpaper is mission impossible i think.
What is the customers purpose for the powder?
(Edited for spelling)


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## capitano9VII (Feb 7, 2022)

Martijn said:


> With iron from a file, which in my opinion should not happen due to the softness of silver, you could use magnetic separation on the powder.
> Sandpaper is mission impossible i think.
> What is the customers purpose for the powder?
> (Edited for spelling)


I don't know the purpose of the client. Thanks for help. i will try a few ways


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## cejohnsonsr1 (Feb 7, 2022)

925 (Sterling) is an alloy in metallic state. You won’t get that all in elemental form (powder) unless you precipitate both separately and mix precisely. Even then it won’t really be 925.


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## orvi (Feb 8, 2022)

I wonder you can dissolve the sterling in nitric and then cement everything with iron - maybe. This only come to my mind. However, i don´t know how silver behave when cemented with iron - if it is flaked off nicely or make hard deposits.


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## kurtak (Feb 8, 2022)

orvi said:


> I wonder you can dissolve the sterling in nitric and then cement everything with iron - maybe. This only come to my mind. However, i don´t know how silver behave when cemented with iron - if it is flaked off nicely or make hard deposits.


the problem with that is you would not actually cement silver/copper 925 alloy 

instead you would cement silver --- and --- copper - as separate metals mixed together in the cement

so you still would not have actual 925 metal alloy

the only real way to do it (other then filing) would be to melt the 925 & then pour the molten 925 through an atomizer which will produce mostly 300 minus mess metal powder 



Water Atomization Equipment - Sugino Machine Official Website



you can make one with a pressure washer - it needs to be a high volume high pressure (so high end commercial) washer - not a cheap small home use washer

you need to make a pipe ring the high pressure water feeds into with 4 nozzles placed 90 degrees from each other around the ring angled downward to the center of the ring

you then set the ring on top of a barrel & then pour the molten metal though the ring 

when the molten metal hits the high pressure water spray it atomizes the metal to powder

Keep in mind you are dealing with very high pressures so it needs to be VERY well constructed --- you don't want it to blow apart on you

Kurt


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## kurtak (Feb 8, 2022)

capitano9VII said:


> Hello everybody. I have a question and I hope one of you guys can help me. I need to make 925 sterling silver powder. I tried this with silver-copper alloy. The copper in it melted because of the acid. The product I got was 999. I need 925. What can I do about it? silver-copper powder must be homogeneous.


How much of this powder do you (or your client) need ?

I ask because building an atomizer it's self is going to be somewhat costly - just for the pressure washer

As I said - you need a high volume high pressure (so high end *commercial*) washer - not a cheap small home use washer

Building one is not as simple as I made it sound in my last post --- you need to consider things like pressure, pipe size, size (diameter) of the ring/donut, nozzle size & type, nozzle placement & angle etc. etc. 

And of course you need to have a furnace for melting the metal

Kurt


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## capitano9VII (Feb 8, 2022)

kurtak said:


> the problem with that is you would not actually cement silver/copper 925 alloy
> 
> instead you would cement silver --- and --- copper - as separate metals mixed together in the cement
> 
> ...


I will concentrate on this method. I can provide the necessary equipment and try. Thank you everyone for your ideas.


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## capitano9VII (Feb 8, 2022)

kurtak said:


> How much of this powder do you (or your client) need ?
> 
> I ask because building an atomizer it's self is going to be somewhat costly - just for the pressure washer
> 
> ...


I have a furnace for melting the metal. My client asked if you could do this. Asked me for an sample product. if i find high pressure washer i could try.


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## capitano9VII (Feb 8, 2022)

What I'm really curious about is the size of the product that will come out. customer wants micron size. can we adjust the particle size by increasing the pressure. @kurtak


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## kurtak (Feb 8, 2022)

an atomizer will make 300 (plus/minus) mesh *powder* (some will be 300 plus - some will be 300 minus (MOSTLY 300 minus) --- that is of course if your atomizer is properly constructed

300 mesh is *about* - 0.05 - micron

here is a mesh to micron chart



http://filtersolutions.com/pdf/mesh%20to%20micron%20conversion%20chart.pdf



300 mesh is VERY fine *powder*

Kurt


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## jobinyt (Feb 8, 2022)

I think you need a better product specification. Will any 925 % silver allow suffice, or must it be a specific alloy? In some physical measure what partical size and size range is required. For instance, does micron truly mean micron and can fines be left in the product? "Mesh' is the usual specification, but even there a fussy client may care about wire size. What is the order volume and frequency? Will you be selling at spot price (probably risky), long term contract, ...?

I suspect your customer knows of many suppliers with reasonably reliable quality and delivery dates. What they seek is a lower price. If the specification is tight (it might be tight it product performance and they might not even realize that) for instance for use in a battery or electrical component, you'll likely not meet it with mixed/home brewed alloy. I learned to always ask potential customers why they wanted a new supplier. Those having their product quailty spec met or were getting late shipments I wanted and got. Those just shopping for lowest available price I didn't want. They are unprofitable, demanding, and will change suppliers for insignificant price differences. Let the seller be aware.


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## kurtak (Feb 8, 2022)

jobinyt said:


> Will you be selling at spot price


Atomized metal powders go from anywhere 2X spot price to 4 - 5 X spot price depending on several factors including but not limited to order size (1 pound or 100 pounds)

They have a VERY wide range of applications

Kurt


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## orvi (Feb 8, 2022)

kurtak said:


> the problem with that is you would not actually cement silver/copper 925 alloy
> 
> instead you would cement silver --- and --- copper - as separate metals mixed together in the cement
> 
> ...


Yes, it´s true. However, it need to be very specialized application, where mixed alloy powder is required. If it is melted in any moment, it would produce the same alloy. 
Atomizing didn´t come right to my mind, too much focused on chemical ways  
Just a question, does reducing/increasing pressure mean reducing/increasing grain diameter ? or it just start to produce all kinds of mesh sizes ? Seems like you have experience with this procedure


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## joekbit (Feb 8, 2022)

capitano9VII said:


> Hello everybody. I have a question and I hope one of you guys can help me. I need to make 925 sterling silver powder. I tried this with silver-copper alloy. The copper in it melted because of the acid. The product I got was 999. I need 925. What can I do about it? silver-copper powder must be homogeneous.


That's a strange request.
925 is 80% pure Ag with an alloy added. In short if you have 100 grams of pure silver you need add (20 grams) of some other element to mix with it. Most commonly Cu (copper), resulting in 120 grams. Use some cemented Ag powder and file some pure Cu as needed for the proper ratio.


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## AustAuScrap (Feb 8, 2022)

Hi,
Interesting subject, concept,
I am guessing someone wants to 3D print some Sterling silver jewellery?
If not it might still be a direction to search out the processes used to make metal lazer printer powders to see if the method might be suitable to process the known Sterling into the required grade powder.
Next question then though is oxidation, the smaller the grains the bigger the surface area to get oxidized. -and will this cause unwanted effects for what ever the powder would be used for.
For instance when I sharpen a drill on my Drill Doctor, the waste from the diamond grinding wheel doesn't take long at all to oxidize because it is so fine. It is also my guess that Sterling would be too soft and clog a diamond wheel to use this as a powder manufacture process.
J


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## FrugalRefiner (Feb 8, 2022)

joekbit said:


> 925 is 80% pure Ag with an alloy added. In short if you have 100 grams of pure silver you need add (20 grams) of some other element to mix with it. Most commonly Cu (copper), resulting in 120 grams. Use some cemented Ag powder and file some pure Cu as needed for the proper ratio.


??? "925 is 80% pure Ag with an alloy added." ??? 

Sterling silver, which is often stamped as 925 is 92.5% silver and 7.5% other metal, usually copper.

Mixing 100 grams of pure silver with 20 grams of another metal would yield an alloy that was 83.33% silver.

Dave


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## orvi (Feb 9, 2022)

joekbit said:


> That's a strange request.
> 925 is 80% pure Ag with an alloy added. In short if you have 100 grams of pure silver you need add (20 grams) of some other element to mix with it. Most commonly Cu (copper), resulting in 120 grams. Use some cemented Ag powder and file some pure Cu as needed for the proper ratio.


925 states for 925/1000. 80% would be 800/1000
Some strange "math" is going here


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## Yggdrasil (Feb 9, 2022)

FrugalRefiner said:


> ??? "925 is 80% pure Ag with an alloy added." ???
> 
> Sterling silver, which is often stamped as 925 is 92.5% silver and 7.5% other metal, usually copper.
> 
> ...


I think 830S is what is considered ordinary silver in silverware.
So the 100-20 is close to that.
But far from Sterling.


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## capitano9VII (Feb 9, 2022)

joekbit said:


> That's a strange request.
> 925 is 80% pure Ag with an alloy added. In short if you have 100 grams of pure silver you need add (20 grams) of some other element to mix with it. Most commonly Cu (copper), resulting in 120 grams. Use some cemented Ag powder and file some pure Cu as needed for the proper ratio.


I think such a mixture would not be 99% homogeneous.


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## capitano9VII (Feb 9, 2022)

jobinyt said:


> I think you need a better product specification. Will any 925 % silver allow suffice, or must it be a specific alloy? In some physical measure what partical size and size range is required. For instance, does micron truly mean micron and can fines be left in the product? "Mesh' is the usual specification, but even there a fussy client may care about wire size. What is the order volume and frequency? Will you be selling at spot price (probably risky), long term contract, ...?
> 
> I suspect your customer knows of many suppliers with reasonably reliable quality and delivery dates. What they seek is a lower price. If the specification is tight (it might be tight it product performance and they might not even realize that) for instance for use in a battery or electrical component, you'll likely not meet it with mixed/home brewed alloy. I learned to always ask potential customers why they wanted a new supplier. Those having their product quailty spec met or were getting late shipments I wanted and got. Those just shopping for lowest available price I didn't want. They are unprofitable, demanding, and will change suppliers for insignificant price differences. Let the seller be aware.


The type of alloy is not important, the important thing is that the alloy is 925 silver. if we can come to an agreement it will be a long term contract. I cannot establish healthy communication with the customer because he provides communication through his Middleman. For now, I'm just trying to get a sample.


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## jobinyt (Feb 9, 2022)

Kurt - yes, I stated that poorly - that there is a raw material price risk to be considered in pricing/agreements.

In any event I think it a mistake to put manufacturing process before product specification and volume and why customer is seeking quote.


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## kurtak (Feb 9, 2022)

jobinyt said:


> Kurt - yes, I stated that poorly -* that there is a raw material price risk to be considered in pricing/agreements.
> 
> In any event I think it a mistake to put manufacturing process before product specification and volume and why customer is seeking quote.*


I agree 

no time to post more today

Kurt


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## PeterM (Feb 9, 2022)

orvi said:


> 925 states for 925/1000. 80% would be 800/1000
> Some strange "math" is going here


925 is exactly what it means .925 Pure


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## samuel-a (Feb 10, 2022)

For additive manufacturing, your best choice would probably be a ready-made powder, designed for this purpose.
Try LEGOR. They are not cheap, but the quality is superb.





Powders for DMLS have to have a well-controlled morphology and size distribution.
Water atomization will usually not provide the desired spherical shape.


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## capitano9VII (Feb 10, 2022)

samuel-a said:


> For additive manufacturing, your best choice would probably be a ready-made powder, designed for this purpose.
> Try LEGOR. They are not cheap, but the quality is superb.
> 
> 
> ...


As a system, the gas atomization system and the water atomization system are almost the same. I have to do the production for the continuity of the work. otherwise, I can't do business.


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## kurtak (Feb 10, 2022)

orvi said:


> Seems like you have experience with this procedure


No - I do not actually have "experience" with it

A few years back I was given *very detailed instruction* for building an atomizer & was considering doing so

However when I looked into it the cost did not justify my needs to produce atomized metal powder

As I said earlier -------



kurtak said:


> As I said - you need a high volume high pressure (so high end *commercial*) washer - not a cheap small home use washer
> 
> *Building one is not as simple as I made it sound in my last post* --- you need to consider things like pressure, pipe size, size (diameter) of the ring/donut, nozzle size & type, nozzle placement & angle etc. etc.



Per the bold print - in the first place - a cheap small home use washer will not do the job

The vast majority of pressure washers out there (that you can buy for a few hundred dollars) will deliver the required 3,500 PSI - *BUT* - they will *NOT* deliver the required 7.5 - 8 GPM --- most of them only deliver 2.5 - 3.5 GPM

So something like this -----------









3500 PSI @ 8 GPM Belt Drive Honda GX690 Truck/Skid Mount Gas Skid Pressure Washer w/ General PumpDefault Title


This 3500 PSI 8.0 GPM Triplex Pump Gas Pressure Washer from BE Power Equipment (B3524HTBG) features an electric start on the engine to allow for easy starts. The belt drive system provides the longest pump life possible by lowering its heat, vibration and RPM. The external unloader provides...




www.toolbarn.com





Only you really want an electric washer rather then a gas washer so you can wire in an on/off foot peddle switch to turn it on & off during operation

When I found electric washers with those specs they had a price tag of $6,000 - $8,000

Then - depending on the application "for the powder" you likely need to set up vibratory screen sifting to classify the resulting powder (so more cost)

Something like the sifter in this video ----------






INCINERATION PROCESS - Advanced Chemical Company







advchem.com





Also - the spray/power head needs to be built to *very tight specs* which means it's not a simple home/garage build - you need it built by a ligament machinist - which is not cheap

So the production needs to justify the cost - my needs did not justify the cost

Kurt


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## jobinyt (Feb 10, 2022)

Ah - and there it is - middleman. The sole interest is cost and the middleman is fully aware of participants in the market.

If you're interested in the business I suggest you look at the whole market - the whole supply chain, and develop a plan to by-pass the middleman - sell direct. Don't put yourself in the position of being dependent on the middleman.


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## samuel-a (Feb 10, 2022)

capitano9VII said:


> As a system, the gas atomization system and the water atomization system are almost the same. I have to do the production for the continuity of the work. otherwise, I can't do business.


I wouldn't know.
I only built a water-based one:


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## silver1 (Feb 10, 2022)

Don't know the volume or application you need this for, but i currently make silver and gold products of various alloys and particle size using laser ablation in a liquid medium. Cost is based on production and quality. I use this for a new product i developed for silver antibiotics applications via inhalation. 10-20 Nanometers. It's small scale for i need it for, but can scale up depending on cost.


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## silver1 (Feb 10, 2022)




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## kurtak (Feb 11, 2022)

This is a test to see if I can copy a pic from a "Word" document & then post the pic here


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## kurtak (Feb 11, 2022)

Ok - that worked

That is a pic of the of first "prototype" power head made by the person that gave me detailed instruction for a metal atomizer

As you can see - his "first" prototype build was made with plain steel so it rusted - the lesson in that is - it needs to be made with stainless steel

Also - I guess I need to back up a bit because I have posted ----------



kurtak said:


> The vast majority of pressure washers out there (that you can buy for a few hundred dollars) will deliver the required 3,500 PSI - *BUT* - they will *NOT* deliver the required 7.5 - 8 GPM --- most of them only deliver 2.5 - 3.5 GPM



you can (likely) build an atomizer using a smaller pressure washer - at least in terms of GPM water delivery (pressure still needs to be 3,000 - 3,500 PSI)

However - pressure - GPM - angle of nozzles - etc. etc. will have a direct effect on particle size

In other words - less pressure AND GPM - may (or not) result in only "busting" the molten metal to a small/fine grain metal particle size rather then true powder --- as well as other factors to be considered

will post more this weekend

Kurt


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## kurtak (Feb 11, 2022)

samuel-a said:


> I wouldn't know.
> I only built a water-based one:
> View attachment 48267



Awesome Sam - & yes that is the general idea

What size pressure wash (PSI & GPM) are you using for that set up ?

Kurt


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## slsmp40 (Feb 11, 2022)

joekbit said:


> That's a strange request.
> 925 is 80% pure Ag with an alloy added. In short if you have 100 grams of pure silver you need add (20 grams) of some other element to mix with it. Most commonly Cu (copper), resulting in 120 grams. Use some cemented Ag powder and file some pure Cu as needed for the proper ratio.


Sterling is 92.5% silver not 80% silver. The 925 is parts per thousand. Industrial production of alloy powders is almost always produced in a ball milling operation and small lab quantities with an apex mill. Both are not equipment you are going to want to acquire without thought at they are not cheap. You would make your alloy in the conventional way and drop it in agitated water to get preferably fine flake then you can mill to size. It would be better if you disclosed a use for the powder as there might be a cheaper way. Alloy powders are not easy to produce compared to pure powders that can usually be made by selective reduction techniques in scalable quantity from grams to tons.


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## capitano9VII (Feb 12, 2022)

samuel-a said:


> I wouldn't know.
> I only built a water-based one:
> View attachment 48267


this is a really nice design, it made me visualize the design in my head


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## capitano9VII (Feb 12, 2022)

kurtak said:


> Ok - that worked
> 
> That is a pic of the of first "prototype" power head made by the person that gave me detailed instruction for a metal atomizer
> 
> ...


I'm looking forward to your ideas


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## samuel-a (Feb 12, 2022)

kurtak said:


> Awesome Sam - & yes that is the general idea
> 
> What size pressure wash (PSI & GPM) are you using for that set up ?
> 
> Kurt



Everything is rated for 3000PSI.
For proof of concept, we hooked it up with a small home pressure washer, rated at 1.6 GPM at about 1000PSI.

To my surprise, it did a very nice job, with about 20% of the melt being above 2mm in size. Here's the result:



There are a lot of factors in play that will determine the particle size, but it seems to me that the most important are those (in descending order):
- Water to Metal flow rate ratio - i.e. the higher the ratio, the smaller particles you'll get.
- Nuzzle angle - the platter, the better. up to a point where it starts up squirt water upwards to the tundish.
- The fluidity of the melt
- The height of the tundish

With this design, I found the fine-tuning of the nuzzles was the most difficult part


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## kurtak (Feb 13, 2022)

Arrrrg - just spent about 3 hours posting a reply - had several other tabs open & went to close some of those tabs - accidently closed the tab for the reply I was working resulting in loosing all my work 

Right now not even going to try to retype it all - Arrrrg

Kurt


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## kurtak (Feb 13, 2022)

samuel-a said:


> Everything is rated for 3000PSI.
> For proof of concept, we hooked it up with a small home pressure washer, rated at 1.6 GPM at about 1000PSI.
> 
> To my surprise, it did a very nice job, with about 20% of the melt* being above 2mm in size*. Here's the result:


Sam - per the bold print - 2 mm in size is about 10 mesh (which is not a true powder)

When classifying "powder" - powder starts at about 80 mesh (80 mesh considered as "course" powder & fine powder starting at about 120 mesh - very fine at about 200 mesh - micro fine at about 300 mesh)

with your set up (roughly speaking) about how much powder at say 100 mesh & finer do you get ?

Kurt


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## kurtak (Feb 14, 2022)

Ok - yesterday I messed up & lost what I spent three hours working on for a post - so will try again today

How does the atomizer power head that I and Sam have posted pictures of work

It works by high pressure water spray hitting the molten metal & busting the molten metal into small/fine particles (or a shear factor)

How small/fine particles the molten metal will bust into depends on a number of factors

1) Pressure - pressure is the force that does the busting apart of the metal when it (pressure) hits the metal - higher pressure means more force - more force means more effective busting --- less pressure in turn means less force which in turn means (edit to add word *less* here) effective busting

2) Disbursement of water delivered by the high pressure spray - this is determined by the nozzles orifice size as well the angle of the "water fan" coming out the nozzle with both effecting the shear factor

Orifices size has an effect on the size of the water droplets coming out the orifice (under pressure) smaller droplets have more energy then larger droplets --- fan angle - a large fan distributes the water AND energy over a larger area then a small fan

3) Angle at which the spray hits the molten metal as the molten metal passes through the spray also effects shear

4) Water volume (GPM) - there needs to be enough water in combination with the three above factors to optimize shear

5) Rate (speed & amount) of molten metal poured through the spray

All of these things have a direct effect on particle size produced by the shear energy to bust the metal according to system design

Regardless of system design - you are not going to get 100% of a given particle size (as in 100% of 50 mesh, 100 mesh, or 200 mesh, 300 mesh)

Reather - the system design will only determine the percentage of course - fine - ultra fine particles produced by the system

Sam was good enough to provide us pics of his system using a 1000 PSI 1.6 GPM pressure washer

Sam's system - though certainly doing a good job of "busting" the metal it also shows a relatively high percentage of course particle size

Here is a pic of the end product using a system with more pressure & more GPM (3000 - 3500 pressure delivering 6.8 - 7.5 GPM)




This pic is a bit deceiving because as you can see it is wet so the particles are clumped together making it look like it is much courser then it actually is

I have another pic of the same material dried but it's in a "paper" document (instead of a document on my computer) & I don't have a scanner to scan it & download it

Based on that picture (of the dry material) it is producing a large percentage of true powder ranging from course (80 mesh) to ultrafine (300 minus mesh)

The bottom line being (as already said) no matter the system - you will get a range of particle size - so sifting will be required if you are after a "classified" particle size --- and again the system will (at least to some degree) determine percentage of course to fine to ultrafine

One more note - regardless of the system - you will have some metal that goes through as "over size" (greater in size then powder) percentage of that will again be determined by the system design &/or the 5 above points

This post was to provide info concerning the principle behind producing metal powder with a pressure washer

My next posting will be to provide more details on actual design of the system

Kurt


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## orvi (Feb 14, 2022)

Very interesting informations given. Thanks for everybody


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## kurtak (Feb 16, 2022)

Currently very busy with other things I must get done - will get back to this ASAP

That may not be until this weekend

Kurt


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## kurtak (Feb 17, 2022)

Sorry I have not got back to this yet - I will get back to it this weekend though

Edit to add; - during the week I only have time for "short" answer/replies

This is a long answer/info/reply thing 

Kurt


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## capitano9VII (Feb 17, 2022)

I will start working as soon as possible to make a prototype. i have doubts about which nozzle should i use. 1 kilo sample requested. need to know nozzle diameters. I'm looking for articles but There is no clear information. I will try to find out by doing a trial run.


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## Cryogaijin (Feb 17, 2022)

Aside from being a bit lossy, would a ball-mill work?


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## capitano9VII (Feb 18, 2022)

Cryogaijin said:


> Aside from being a bit lossy, would a ball-mill work?


This method works for pure silver. Not suitable for alloys. And I don't think it's suitable for micron sizes.


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## kurtak (Feb 18, 2022)

capitano9VII said:


> I will start working as soon as possible to make a prototype. i have doubts about which nozzle should i use. 1 kilo sample requested. need to know nozzle diameters. I'm looking for articles but There is no clear information. I will try to find out by doing a trial run.


As I said I will post details for making the power head (donut) *this weekend*

typing up such a post with *details* takes time - LOTS OF TIME

I don't have that kind of time during the week - which is why I said I would do it this weekend

You have two options

you can experiment by trying to build one with the lack of details & off a couple pics in which case angles etc. etc. etc. will likely be wrong & need to rebuild 

Or you can wait till I have the time (this weekend) to post the details --- & you can build it right the first time

If you are going to waste your time experimenting --- then there is no sense in me wasting my time to give you proper instructions

Keep in mind - that I am not being paid to help you here - so I am not working on your clock but rather on my clock --- which in turn means you simply have to wait until I have *the free time *to do so (which as I said would be this weekend)

It would be one thing if the instructions I have were on my computer where I could just copy & paste them here

But they are not on my computer - they are in "paper documents"

That means I have to go over them (a page at a time) & then hand type them here --- that takes a LOT OF TIME

Sorry if that all sounds rude - but I am working for free to try to help you --- so WAIT & I will give you the proper instructions --- it's only a couple more days that you have to WAIT for proper instructions to do it right THE FIRST TIME

Kurt


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## capitano9VII (Feb 18, 2022)

kurtak said:


> As I said I will post details for making the power head (donut) *this weekend*
> 
> typing up such a post with *details* takes time - LOTS OF TIME
> 
> ...


I appreciate your effort. you helped me a lot. I will wait for you.


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## cejohnsonsr1 (Feb 19, 2022)

I see this keep popping up and wondering why? Making a mixture of powdered metals at a given ratio is child’s play. No more difficult than mixing flour for bread. The real question is why so much concern? It won’t be Sterling unless or until you melt it into an alloy and once you start that the only thing that matters is the weight and purity of the metals. The form is absolutely irrelevant.


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## kurtak (Feb 19, 2022)

cejohnsonsr1 said:


> I see this keep popping up and wondering why? *Making a mixture of powdered metals at a given ratio is child’s play.* No more difficult than mixing flour for bread. The real question is why so much concern? It won’t be Sterling unless or until you melt it into an alloy and once you start that the only thing that matters is the weight and purity of the metals. The form is absolutely irrelevant.


Per the bold print --- you have missed the whole point of this thread - we are *not* talking about *making* sterling (which yes - would be made by taking 92.5% silver & 7.5% copper & melting it together resulting in the alloy of sterling silver (925 silver)

Rather - this thread is about taking sterling silver that is already the alloy (of 925 silver) & turning that alloy into powder

In other words - turn (actual) sterling into powder --- not make sterling from silver/copper powders

Why do you want to do that ?

Because - if you can turn actual sterling into a powder you can use that sterling powder for MANY things including but not limited to - 3D printing sterling objects - making sterling glazes - sterling paste type solder - sterling inks - or sterling powder coatings - etc. etc. etc. 

So again (at the risk of repeating myself) *we want to make sterling into a powder* --- not take silver powder & copper powder & make it into sterling

Kurt


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## kurtak (Feb 19, 2022)

Let's start with this ------

*The more pressure you have, the finer the powder you make.*

The point I am making here is that you can make a "proto type" using a small home use pressure washer - like the one Sam posted (For proof of concept, we hooked it up with a small home pressure washer, rated at 1.6 GPM at about 1000 PSI) --- but all that is going to do is prove the concept that a pressure washer will bust molten metal into small particle size - but we already know that this works

What this won't do is tell you how much actual powder can/will be made (which is the end goal) by operating at higher pressure & higher GPM in order to optimize production of powder

We already know a pressure washer will bust molten metal - but our goal is not to just bust metal - rather it is to optimize powder production - So IMO - it only makes sense to build for optimized powder production in the first place 

Other wise all you are doing is building to prove what we already know --- & then re-building to optimize - what we already know

The power head I posted a pic of is built with that in mind (operate at higher pressure & higher GPM) for optimum powder production 

Once this system is built - there are a few things you can alter (such as rate of the molten metal pour - orifice size - nozzle fan - ect.) to achieve your most desired output

With that said - I will next post the materials needed for building the power head/system I posted a pic of

Kurt


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## capitano9VII (Feb 19, 2022)

Features of the air compressor I have : 10bar 1150lt/m 10hp/7.5kW 240kg


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## kurtak (Feb 19, 2022)

*First & foremost* - before we move forward with this build there needs to be a *WARNING* that goes with the build

This system is made to operate at *VERY high pressure* (3000 - 3500 PSI) - & it is made using welded fittings

Therefore - it is *important* that the welds be done by someone that is *VERY GOOD* in the field of stainless steel welding 

*Bad welds can & will result in failure of the power head *--- at best that failure could be pin holes &/or cracks resulting in water spraying everywhere - &/or - at worst - the power head actually blowing apart resulting in serious injury to someone being hit by pieces of steel flying across the room

Bottom line - unless you are *VERY GOOD *at welding SS - do *NOT* build this yourself - pay a *professional* to weld it for you

It is a good idea (& i recommend) to have the welds X-rayed to insure there are no weak spots in the welds

-------------------------------------------------------------------------------------------------------------------- 

Pressure washer size 3000 psi @ 6.8 GPM - or - 3500 psi @ 7.5 GPM


The power head "*donut*" is made using (4) --- 304 SS - 3 inch - *schedule 80* - 90 degree - weld type - *short radius* elbows like these (you do not want to use long radius elbows)









3 inch short radius schedule 80 304 Stainless Steel 90 deg weld on elbow


Elbow type: weld on short radius 90 degree, Material: 304 Stainless Steel per ASTM A403 , Dimensions conform to ASME B16.9, Schedule: 80, Nominal Pipe Size: 3 inch, Outside Diameter: 3.5 inch, Inside Diameter: 2.9 inch, Wall Thickness: 0.300 inch, Center to Center A: 3 inch, Approx Weight: 3.8 LBS



www.pipefittingsdirect.com





(1) --- 1/2" socket weld - class 6000 - threaded half coupling - 304 SS --- this is welded to the donut in order to connect the pressure washer hose to the power head donut - therefore this thread size needs to match the threads on the end of the pressure washer hose (or will have to use an adapter if the 1/2 coupling has different threads then the hose end threads)

You are looking for something like this except you want it to be 6000 class not 3000 class









part# SS.375 3000# THD HALF COUPLING Stainless -


Steel Supply, L.P. is the leading online supplier for Pipe Fittings including Forged Stainless Couplings such as SS.375 3000# THD HALF COUPLING. All Forged Stainless Couplings ordered by noon will ship today.




www.steelsupplylp.com





(4) --- 1/4" socket weld - class 6000 - half coupling - 304 stainless (like in the above link) --- these are welded to the donut for screwing the nozzles into so actual thread size is determined by the thread on the spray nozzles

You do not want to use adapters in this case so make sure the treads of your half couplings & nozzles match

(4) treaded nozzles --- using 4 standard - size 2 - nozzles will deliver 1.7 GPM (per nozzle) at 3000 psi and 1.87 GPM (per nozzle) at 3500 psi.

Therefore - using 4 nozzles @ 3000 psi a pressure washer delivering 6.8 GPM is needed and at 3500 psi 7.5 GPM 

*WARNING --- you do NOT want to use quick connect nozzles --- use ONLY threaded nozzles*

Spray pattern of the nozzles --- you want 7.5 degree *flat fan* spray pattern if possible --- but 15 degree works if you can't find the 7.5.

You will also need a piece of straight SS pipe - this pipe is placed in the center of the "donut hole" so needs to fit "down" into the donut hole --- this pipe protects the nozzles from molten metal. It is best to have the angled nozzles release their spray right at the end of the pipe. This protects the nozzles from accumulating little balls of frozen metal. It will still accumulate some from spray but minimal if the pipe protects it well. 

So the length of this pipe well be determined by the measurement from the top of the donut to the bottom of the nozzles

This is enough for today & will at least get you started in what you need to look for to do this build

Will post more again tomorrow --- it is likely going to take a couple more days to post all the details for this build

Kurt


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## cejohnsonsr1 (Feb 19, 2022)

kurtak said:


> Per the bold print --- you have missed the whole point of this thread - we are *not* talking about *making* sterling (which yes - would be made by taking 92.5% silver & 7.5% copper & melting it together resulting in the alloy of sterling silver (925 silver)
> 
> Rather - this thread is about taking sterling silver that is already the alloy (of 925 silver) & turning that alloy into powder
> 
> ...


I think I understand the question better now, but the answer is really still the same. And please believe me when I say I’m not trying to be facetious or adversarial. When you talk about a metal in powder form, it’s referred to as “elemental” because it is quite literally the atoms of the element(s) (in this case silver and copper) in pure form. Sterling is an alloy of those 2 metals in metallic form. To get to the elemental form you necessarily have to remove everything that isn’t the element in question. To get what you’re describing would require the ability to combine 2 elements in very precise ratios in quantities so small that you’d literally be counting atoms and then melting them in those quantities tens of millions of times per gram. I hope this is a better answer, though I’m sure it’s not the one you were hoping for. It’s just that elemental metals and alloys are mutually exclusive of each other by their very definition.


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## cejohnsonsr1 (Feb 19, 2022)

I think just a little further elaboration is in order. You can dissolve Sterling and have a solution that is the correct ratio of the 2 metals, but at that point you no longer have Sterling. You have a solution containing 2 elements. You can precipitate the silver and leave the copper in solution, or you can precipitate both (see the reactivity series of metals), but again, you won’t have Sterling. You’ll have a mixture of 2 metals in the ratio required to alloy them back into Sterling. What you have described would require that every 925 atoms of silver remain bonded to 75 atoms of copper during precipitation. There is no such method. Again, I’m not trying to give you a hard time. I see what you’re trying to do and there may be some way to accomplish your end goal, but this isn’t it and I hate to see you waste your time,effort and money on something that can’t work when you could possibly direct your energy to something that could work. And I wish you good luck in the endeavor.


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## Yggdrasil (Feb 20, 2022)

cejohnsonsr1 said:


> I think just a little further elaboration is in order. You can dissolve Sterling and have a solution that is the correct ratio of the 2 metals, but at that point you no longer have Sterling. You have a solution containing 2 elements. You can precipitate the silver and leave the copper in solution, or you can precipitate both (see the reactivity series of metals), but again, you won’t have Sterling. You’ll have a mixture of 2 metals in the ratio required to alloy them back into Sterling. What you have described would require that every 925 atoms of silver remain bonded to 75 atoms of copper during precipitation. There is no such method. Again, I’m not trying to give you a hard time. I see what you’re trying to do and there may be some way to accomplish your end goal, but this isn’t it and I hate to see you waste your time,effort and money on something that can’t work when you could possibly direct your energy to something that could work. And I wish you good luck in the endeavor.


I think you need to reread.

No one is talking about dissolved metal here, we are talking about melted metal in an alloy form.
And he want to make it into a micron sized powder as uniform as possible for some application.
Maybe 3D printing or soldering as Kurt said.
Only his customer know.


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## kurtak (Feb 20, 2022)

As I said yesterday --- "you have missed the whole point of this thread" --- & it is still clear you have missed the whole point - in fact you are not even understanding what is being discussed here

We are *NOT* talking about breaking metal down to it's "individual" elemental atoms

Rather we are talking about breaking metal down to an ultra fine (micron size) powder

That process (although not actually breaking the metal to "individual" atoms) is called atomizing (or atomization)

The system for doing this is called an atomizer

In this system/process - atomizer/atomizing/atomization is *NOT* a reference to "individual" atoms - but rather a reference to a particle micron(s) in size

Example; - a 400 mesh particle of metal is about 37 microns in size - a 37 micron particle of metal will have *MANY* atoms in it - if the original (large piece) of metal that the 400 mesh particle came from was sterling or brass (an alloy) then that 400 mesh particle will also be sterling or brass



cejohnsonsr1 said:


> I think just a little further elaboration is in order. You can dissolve Sterling and have a solution that is the correct ratio of the 2 metals


Correct/true


cejohnsonsr1 said:


> , but at that point you no longer have Sterling. You have a solution containing 2 elements.


Correct/true


cejohnsonsr1 said:


> You can precipitate the silver and leave the copper in solution, or you can precipitate both


Correct/true


cejohnsonsr1 said:


> (see the reactivity series of metals),


I am *FULLY *aware of the reactive series


cejohnsonsr1 said:


> but again, you won’t have Sterling.


Correct/true


cejohnsonsr1 said:


> You’ll have a mixture of 2 metals in the ratio required to alloy them back into Sterling.


Correct/true


cejohnsonsr1 said:


> What you have described would require that every 925 atoms of silver remain bonded to 75 atoms of copper


Correct/true


cejohnsonsr1 said:


> during precipitation.


This is where you are wrong because we are not trying to precipitate metals from a solution

Rather - we are trying to turn an existing alloy into micron size particles of that alloy

*In the industry* - that is called atomization & it is done with a system called an atomizer


cejohnsonsr1 said:


> There is no such method


Wrong again - it is in fact - a method/process *used in industry !!!*


cejohnsonsr1 said:


> . Again, I’m not trying to give you a hard time. I see what you’re trying to do


Wrong again - you don't see at all what I am trying to do !!!


cejohnsonsr1 said:


> and there may be some way to accomplish your end goal


Correct - here is a link to accomplishing this very goal - in the *industry *of metal atomization



Water Atomization Equipment - Sugino Machine Official Website



And another link - in the industry






Metal Powders







www.stewardmaterials.com








cejohnsonsr1 said:


> , but this isn’t it


So wrong again - because what I am doing -* is in fact it !!!*


cejohnsonsr1 said:


> and I hate to see you waste your time,effort and money on something that can’t work


Therefore - because *it DOES work* - I am certainly not wasting anything - because what I am doing is passing on the *actual* info - *that in industry* - is called metal powder atomization - done with what (in industry) is called a metal powder atomizer 


cejohnsonsr1 said:


> when you could possibly direct your energy to something that could work.


So my energy is *in fact* directed to something already *proven* to work


cejohnsonsr1 said:


> And I wish you good luck in the endeavor.


Therefore - no luck - what so ever - involved - because it is already a proven industrial process/method

In other words --- in the industry (of making micron size metal particles) the words - atomization - atomizing - atomizer is *NOT* a reference to actual individual atoms - but rather a reference to a process of making ultra fine - micron size - metal powders

That can be done with pure metal - OR - with alloys of metals

You can buy atomized metal powders on ebay - including (but not limited to) stainless steel - which is an alloy

atomized metal powder | eBay

Kurt


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## kurtak (Feb 20, 2022)

Picking up where I left off yesterday

The size match to the GPM of the pressure washer and the PSI of the pressure washer determines the nozzle selection --- If the nozzle hole is too small the pump produces more than the flow out of the nozzles it can cause trouble --- if the nozzle hole is too large performance is compromised. 

It is best if you can select a pressure washer where the pressure is adjustable for fine tuning.

Here is a close up picture of the power head I posted a few days ago




In this picture you see the pipe in the center of the donut that I talked about yesterday

you also see the 1/4 inch half couplings - that the nozzles screw into - welded into the power head

The placement of the half couplings & nozzles should be done by a machine shop to insure proper placement of all 4 nozzles thereby insuring a nice uniform spray pattern (the spray from each nozzle comes together at the same point)

The angle of the spray from the nozzle to the point where it intersects the molten metal can range between 30 and 45 degrees but all must be the same angle so the majority of the waters energy hits the stream of molten metal from 4 sides at the same time, this is what in part effects the particle size --- in other words - this in part along with the other (5) points I posted a few days ago

As a side note - in this (above) pic - you see two round dots - one to the left & one to the right - I have no idea what those are & they are not described in any of the righten documents I have so apparently have no real function

Here is a pic showing the basic principle/idea




This picture shows the connection of the water supply hose coming from the pressure washer to the donut power head - as well as three rods welded to the donut that stabilizes the power head when it is sitting on top of the container that catches the metal powder (like a 55 gallon drum)




I am not sure how many pictures I can put in one post so will end this one & go to another post

Kurt


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## kurtak (Feb 20, 2022)

Here is a picture of the complete unit sit on a 10 gallon catch tank

notice that in this pic there is a lid on the 10 gallon tank - there is a hole in the lid - with a seal between the donut & lid so that there is a snug fit between the donut & lid

you can use a 55 gallon drum for doing larger pours --- there are a few other details you need to be aware of but I will post about that in another post




Here is a picture of the molten metal being hand poured through the atomizer donut power head

This set up - pouring directly through the center pipe is usually sufficient for melts up to 150 ounces.




You can have more control over the flow rate of molten metal through the atomizer by having the molten metal flow through a crucible that has a hole in the bottom of the crucible like this




The crucible of course needs to be (& kept) *RED HOT* so the molten metal does not freeze up in the crucible - so you need to figure out how to do that if going with this method instead of doing a normal hand pour

This - when properly set up - will allow you to do larger & more controlled pours of the molten metal

These are all the picture I have on my computer --- I have more pictures but they are in paper documents so can't post them here as I don't have a scanner --- sorry about that

This is enough info for now

I will post more details again later --- if not later today - then tomorrow

Kurt


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## Racoon (Feb 20, 2022)

kurtak said:


> Let's start with this ------
> 
> *The more pressure you have, the finer the powder you make.*
> 
> ...


Your post is interesting, why don’t you make a happy you tube post showing your production


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## grainsofgold (Feb 20, 2022)

there are a few companies that will atomize metal for a fee. less money than building or setting up a machine. names escape me now. They were on the east coast.


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## cejohnsonsr1 (Feb 20, 2022)

Ok, so then I’m just going to cut to the chase and ask the question that seems most obvious to me. If such a device already exists, why don’t you just buy one?


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## nickvc (Feb 21, 2022)

cejohnsonsr1 said:


> Ok, so then I’m just going to cut to the chase and ask the question that seems most obvious to me. If such a device already exists, why don’t you just buy one?


I’ll take a guess and say because they are horrendously expensive or only made by the companies using them or both.


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## kurtak (Feb 21, 2022)

Some videos that might be of interest





__





metal powdwer atomization - Search Videos







www.bing.com









__





metal powdwer atomization - Bing video







www.bing.com









__





metal powdwer atomization - Search Videos







www.bing.com





Kurt


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## kurtak (Feb 21, 2022)

cejohnsonsr1 said:


> *If such a device already exists,* why don’t you just buy one?


Per the bold print - It's not a question of *IF* --- the fact is they do exist (as shown in the videos I just linked)

As to why not just buy one - anything you can/will find out there on the market - as Nick pointed out is going be horrendously expensive

Just guessing here but I am willing to bet the instructions I am providing for a DIY build is probably (plus/minus - more likely minus) one tenth the cost anything you will find one the market

Kurt


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## kurtak (Feb 21, 2022)

So - picking up from where I left off yesterday 

A few more things to be aware of

You will find that it is near impossible to keep scale from developing inside the donut - either from welding during fabrication or whatever - the small pubic hair sized orifice of the spray nozzles are easy to clog and it is difficult to see when they clog. --- so it is best if you can find nozzles with built in screens/filters to prevent this. They are harder to find and a bit longer but worth it.

As has already been said - The more pressure you have, the finer the powder you make. Get your nozzles to match the output of your pressure washer, so the flow through 4 nozzles at full pressure will equal or be close to the total GPM output of the washer

Speaking of pressure washers --- you basically have 2 options - gas powered washers or electric powered washers 

The electric power washers are nice and controlling them with a foot switch is convenient because with a foot switch one person can turn the washer on & off when you go to make your pour - but gas powered units are cheaper and work well too - you just need to have help so when you are ready to pour someone turns on the washer. 

yesterday I said; - notice that in this pic there is a lid on the 10 gallon tank - there is a hole in the lid - with a seal between the donut & lid so that there is a snug fit between the donut & lid

The purpose of the lid on the powder catch vessel (drum/tank) is to prevent water splash back (remember you are operating at HIGH pressures

But also - blowing the high pressure water into the drum causes the mist to try to get out to equalize pressure.

So - if you use the tundish set up (crucible with hole in the bottom of the crucible) to do your pours - having the lid on the powder catch vessel causes the pressurized spray water mist up at the hot crucible - not good. 

So if you put a hole in the side & near the top of the catch vessel - or in the lid that you can hook a shop vac up to that will help to draw the mist away from the pouring hole. 

Your powder catch vessel (which you are also filling with water) somewhat determines the size pour you can make

Example; - a pressure washer with an output of 6.8 GPM will fill a 55 gallon drum in 8 minutes (realistically -you would want to stop at a max of - plus/minus - 45 gallons) so you can calculate from there (depending on pressure washer selection etc.)

This atomizer system will process *about* 2 ounces of molten metal per second

I say about because it somewhat depends on pour rate - washer selection etc. etc.

So again you can make calculations from there

You could set your system up to recirculate the water - *HOWEVER* - there is one more factor to consider in the process of metal powder atomization 

Cold water coming in contact with hot metal has *much more* explosive energy then hot water coming in contact with hot metal --- therefore water temp - at least to some degree will also have somewhat of an effect on the particle size of your atomized powder output 

This should be enough info to at least get you started for building a metal powder atomizer

If you have any question feel free to ask & I will do my best to answer 

Keep in mind - I have never personally built one - I am simply passing on info from documents I have been provided with

And by all means - please take heed of the warnings I have provide - this is not a toy & if you take shot cuts & hurt yourself &/or someone else that is on you as I have provided all the info for building this & building it right

That includes having the welds done professionally *AND* having them x-rayed 

Kurt


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## capitano9VII (Feb 21, 2022)

You have created a truly excellent guide. thanks for your hard work. I will review. I will gather the necessary equipment and meet with someone for the installation (welding, material supply). I will contact you again after making progress. I will have questions.


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## AustAuScrap (Feb 21, 2022)

Thank You for the effort and valuable time you have used to help to help this other member.
I hope he remembers you and your consultancy work if he ever goes commercial with his project.
I have found the attention to detail and safe operations exemplary as has been your tolerance of "nay sayers" and detractors.
Best Wishes from this side of the world, Keep Up the meticulous standards of your work.
J


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## kurtak (Feb 23, 2022)

One more document I found (yesterday) on my computer

Edit to say I deleted the link because it did not work

Opps - it's a PDF & apparently I can't just copy & past it (it's in my down loads files not my documents file

So I will have to figure out how to put it up here

Kurt


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## FrugalRefiner (Feb 23, 2022)

Include it as an attachment. See my Tips thread.

Dave


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## kurtak (Feb 24, 2022)

Here is the PDf I tried to post yesterday

Kurt


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## samuel-a (Feb 25, 2022)

Good job explaining all of this, Kurt.

A strange circumstance had me deliver my build to the client before I could test it at higher pressure (as it was designated to work at 3000PSI and built accordingly).

It is worth mentioning again that the variable having the most significant effect on particle size is the amount of water per second passing through the apex.
To achieve this, one needs his contraption to accommodate fine-tuning of the nuzzles and make sure to use a 0-15° fan angle (depending on the apex distance).


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## capitano9VII (Feb 26, 2022)

First products, 925 silver powders. @kurtak I will send it to the lab to find out the size.


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## kurtak (Feb 27, 2022)

capitano9VII said:


> First products, 925 silver powders. @kurtak I will send it to the lab to find out the size.



capitano9VII - thank you very much for posting the pics of your first powder - it's good to see the results of time spent providing info

Although pictures can be deceiving it looks like very nice powder with relatively high percentage of very fine to ultra fine

As I said - the atomizer will produce a "range" of particle sizes so it will be good to hear back the report from the lab & most important if it is serving the needs of your client

Kurt


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## kurtak (Mar 3, 2022)

capitano9VII said:


> First products, 925 silver powders. @kurtak *I will send it to the lab to find out the size.*



capitano9VII - any word back from the lab yet on the powder size ?

Kurt


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## capitano9VII (Mar 3, 2022)

kurtak said:


> capitano9VII - any word back from the lab yet on the powder size ?
> 
> Kurt


No news yet. I will let you know as soon as the results come out. @kurtak


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## kurtak (Mar 3, 2022)

Ok - thank you - was just wondering

Kurt


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## Alondro (Mar 3, 2022)

orvi said:


> 925 states for 925/1000. 80% would be 800/1000
> Some strange "math" is going here


Common Core math, I'm wagering. ;]


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## kurtak (Mar 25, 2022)

capitano9VII said:


> First products, 925 silver powders. @kurtak I will send it to the lab to find out the size.


Just wondering about the results on this ?

Kurt


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## capitano9VII (Mar 25, 2022)

My client's partner is Ukrainian. We have not made any progress yet due to these events. I sent the sample product to the customer. I will contact you as soon as I get the information. @kurtak


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