is it possible 925 sterling silver powder

[Yggdrasil]

??? "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

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

 

[capitano9VII]

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.

 

[capitano9VII]

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.

 

[jobinyt]

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.

 

[kurtak]

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

 

[PeterM]

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

925 is exactly what it means .925 Pure

 

[samuel-a]

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.

 

[capitano9VII]

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.


View attachment 48262

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

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.

 

[kurtak]

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 -------

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 -----------

https://www.toolbarn.com/products/b...tbg_&msclkid=6c20886605dc1e5ad2e0ea63047f24cc
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 ----------

https://advchem.com/videos/19-videos/64-acc-incineration-process
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

 

[jobinyt]

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.

 

[samuel-a]

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:

 

[silver1]

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.

 

[silver1]

 

[kurtak]

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

 

[kurtak]

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 ----------

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

 

[kurtak]

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

 

[slsmp40]

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.

 

[capitano9VII]

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

 

[capitano9VII]

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 ----------



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

I'm looking forward to your ideas

 

[samuel-a]

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