# Flux



## denmark1982 (Jan 22, 2017)

hello again  

i have a question concerning Flux

can i use ordinary Flux or what..  or must i buy some other Flux


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## patnor1011 (Jan 22, 2017)

Seriously?

Would you care to provide more details? 
Without telling what you want to use it for it is like asking how many stars are out there.


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## galenrog (Jan 22, 2017)

The material you are working with will determine the flux mixture. What is you feedstock, and what are your goals with that feedstock? We will need to know all details in order to properly answer your question.

Time for more coffee.


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## butcher (Jan 22, 2017)

denmark1982,
The question is too broad of a subject to give you an answer. Especially without you giving us any details of what you are trying to melt and what you are wanting to do chemically in that melt.
What color is a flower?

There are many different kinds of flux; many different things can be used as flux, each has a specific function, most react chemically in the melt, and are added for specific reasons.

Knowing how each cheimical (flux), metals, or minerals react in the melt can help you to decide what flux may work the best, or how to adjust the flux composition to improve the characteristic of the melt to achieve the desired result.


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## denmark1982 (Jan 24, 2017)

butcher said:


> denmark1982,
> The question is too broad of a subject to give you an answer. Especially without you giving us any details of what you are trying to melt and what you are wanting to do chemically in that melt.
> What color is a flower?
> 
> ...



melting gold and am using aqua regia


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## Topher_osAUrus (Jan 24, 2017)

Pure gold requires no flux.

Only a thin layer of borax glazed on the dish to capture any impurities you may have missed.

After a couple times of being in solution, and proper washing and rinsing techniques, you should have no contaminants though.


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## anachronism (Jan 24, 2017)

Topher_osAUrus said:


> Pure gold requires no flux. Correct!
> 
> Only a thin layer of borax glazed on the dish to capture any impurities you may have missed. If it's pure then there are no impurities to miss  That given, if your crucible isn't holy and your gold is pure you don't need any borax at all to melt your gold.
> 
> After a couple times of being in solution, and proper washing and rinsing techniques, you should have no contaminants though.


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## Topher_osAUrus (Jan 24, 2017)

Really?!?

So, I can melt in a plain ol' brand new melt dish Jon?

Fresh out the box (slowly heated up to remove moisture, of course)
I need not glaze it?

That's good to know!
Thank you sir


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## anachronism (Jan 24, 2017)

Yes you can quite happily Toph.


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## Topher_osAUrus (Jan 24, 2017)

Excellent.

I have a couple dishes that I have yet to flux. Might just give that a try.

Is it a pain in the rear to get any prills to move to the main mass of metal? Or any other idiosyncrasies of the flux-less process I should be aware of?


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## jeneje (Jan 24, 2017)

Topher_osAUrus said:


> Excellent.
> 
> I have a couple dishes that I have yet to flux. Might just give that a try.
> 
> Is it a pain in the rear to get any prills to move to the main mass of metal? Or any other idiosyncrasies of the flux-less process I should be aware of?


You can, but it won't flow easily and you'll lose some gold in the melt due to it sticking to the dish.

Ken


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## g_axelsson (Jan 24, 2017)

I haven't tried to melt gold in a "dry" melting dish. Wouldn't the gold stick to the dish without borax?

The borax also helps as a lubricant so it is easier to collect all the small droplets of gold in one big button.

Göran


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## anachronism (Jan 24, 2017)

g_axelsson said:


> I haven't tried to melt gold in a "dry" melting dish. Wouldn't the gold stick to the dish without borax?
> 
> The borax also helps as a lubricant so it is easier to collect all the small droplets of gold in one big button.
> 
> Göran



Give it a go mate. Look there's no harm in using a smidge of borax but if the question is "is it required" then the answer is no for pure gold.


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## solar_plasma (Jan 24, 2017)

I remember from my early experiments using no borax, the gold will stick to the dish (if made of clay) if it cools down in it. If you remove the gold button with a screwdriver and some force, you will break off some clay from the dish.

Further the color of the borax will indicate many possible impurities.


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## 4metals (Jan 24, 2017)

Large melts of fine gold are done without flux for both bars and pouring shot. But small torch melts benefit from the glaze and as Solar pointed out, the added color indication helps you to determine how well you processed the gold as metal oxides of contaminants will show up in the glaze color. Rolling around molten balls of metal and having them collect into one pool is difficult without a thin glaze.


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## kurtak (Jan 25, 2017)

To clarify - concerning not needing to glaze a melting dish (as posted by Jon)

As eluded to by 4metals in this statement


> Large melts of fine gold are done without flux for both bars and pouring shot.



Size of melt makes a difference as to whether or not melting in an unglazed dish can/will present a problem or not

This question came up on RPM so rather then retype my answer here - I am going to simply copy it to here

My reply on RPM -------------

For what its worth - over glazing your melting dish can/will cause the same problems as not glazing it at all - your molten gold will hang up in the thicker glaze (in other words not roll about easily in the dish) & small beads will still hang up in the thicker layer of glaze

Whether not glazed at all - or over glazed - the problem with the gold hanging up in the dish &/or small beads sticking to the dish is only really a problem if it is a small amount of gold being melted (say a half ozt or less) & that's because when the gold gets molten it doesn't have enough weight to move against the resistance of the rough surface of an unglazed dish &/or move against the resistance of a thicker over glazed dish --- in other words whether the dish is not glazed or over glazed the problem of the gold not rolling about in the dish to pick up the beads (that end up stuck in the dish) is made greater the smaller the amount of gold you are trying to melt

If you are melting say on ozt of gold or more at a time the molten gold will then have enough weight that it will roll about in an unglazed dish to pick up any & all beads that may sick to the sides --- in fact it will do so better in an unglazed dish then in an over glazed dish

So -Jon - who posted about not needing to glaze the dish (on GRF) is absolutely right in saying you don't need to glaze the dish - Jon is used to melting "at least" an ozt (& he considers that a small melt) & more often then not he is melting 3 - 5 ozt at a time --- I am sure that because Jon is used to doing "large" melts he simply did not think about how "size of melt" plays a roll in whether or not glazed or not glazed (or over glazed) effects the melt --- I will post to that thread to clarify

Bottom line - Jon is right - no need to glaze the dish "if doing larger melts"

You do still NEED to preheat &/or "slowly" heat the dish to drive out moister - or the dish will crack if you heat it to fast

Kurt


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## Geo (Jan 25, 2017)

Even though it's possible and some people do it that way, it is recommended that you glaze a melting dish to torch melt gold. The opposite is true for graphite. Do not glaze graphite because it does not have the same properties of fused silica or clay melting dishes. Graphite is non-stick and the borax basically fouls the graphite surface. The exception is smelting in graphite crucibles.


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## Geo (Jan 25, 2017)

I forgot to add, if you are melting by torch, there will be some contamination. Even if you start with chemically pure gold, if you melt it with a torch with a copper tip, it will have copper contamination. It may not be much but when you are talking about purity, it doesn't take much. Borax will soak up that small amount of copper contamination.


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## Lou (Jan 25, 2017)

Geo said:


> I forgot to add, if you are melting by torch, there will be some contamination. Even if you start with chemically pure gold, if you melt it with a torch with a copper tip, it will have copper contamination. It may not be much but when you are talking about purity, it doesn't take much. Borax will soak up that small amount of copper contamination.




Very astute observation.

For this reason, high purity gold that I make is melted in glassy carbon.

Lou


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## kurtak (Jan 26, 2017)

Geo said:


> Even though it's possible and some people do it that way, it is recommended that you glaze a melting dish to torch melt gold.



Correct - glazing a dish has always been recommended - as it should be - especially if you are doing small melts of just a "few" grams (as already explained/discussed) --- its just not "necessary" 

Jon can correct me if I am wrong - but I don't think he made his comment "as a recommendation" - he was simply making a point that it is not "necessary" --- in other words doable --- to which - being how it came up I felt the need to post a more detailed explanation of the pros & cons to melting in a glazed or unglazed dish

Keep in mind - as I pointed out - "over" glazing a dish can/will present its own problems - something rarely mentioned - people are just told to glaze their dish

The point being - Jon was/is not wrong &/or posting mis-information in "pointing out" that it is not "necessary" to glaze your dish - in fact - IMO - Jon pointing out the fact that it is not necessary to glaze a dish opened this "fact" for discussion such that it provides members the opportunity to make a decision based on their circumstance

Let me put it this way --- why would I waste the half hour or so it takes me to "properly" glaze a dish in a situation where it is not necessary

Example; - say I have a ozt or more of karat scrap I want to melt to pour shot to go to AR (assuming of course I don't already have a glazed dish handy for the job) why would I waste a half hour of my time to do this melt - when it is not necessary

IMO - telling me I "need" to glaze my dish - is in fact mis-information :!: 

There is one more thing about using a unglazed dish that should be pointed out - if you are melting impure gold powders - the impurities tend to forum oxides (of the base metals) "on the surface" of your molten gold - you don't always see them while the gold is molten - but they will be clearly evident when the gold cools --- because these oxides tend to be on the surface of the molten gold - & if you are using an unglazed dish - when you roll the gold in the dish - to pick up beads - &/or when you make the pour - the gold tends to roll out from under these oxides with the oxides hanging up on the rough surface &/or on the pour spout lip of the unglazed dish - the slower you roll the gold &/or slower the pour the more likely the gold is to roll/pour out from under the oxides - leaving the oxides hung up on the rough surface of the unglazed dish --- these oxides will show up as a streak as the gold rolls out from under it - if it's a bead of pure gold that hangs up on the rough surface of the unglazed dish - it will show up as a bead instead of a streak - which can then be picked back up by bring the larger pool of molten gold back around to it

What does that mean? --- it means when melting your powders (assuming your melt is big enough to work properly in an unglazed dish) you can use the dish to "somewhat" determine if your gold is actually clean or not by doing a "slow" roll of the molten gold in the dish to see if oxides hang up on the rough surface 

If so - & you are thinking ahead - you can have your water bucket for pouring shot already hand & you can decide to pour it to shot for going back to AR - rather then pouring it to a mold & ending up having to re-melt the mold pour to make shot for AR again 

IMO - recommending glazing a dish should certainly stand as the "standard recommendation" --- but trying to discredit not glazing a dish as an option does not serve the purpose of this forum which is to provide information such that members can make informed decisions that best serve their circumstances

I hope between the fact that Jon brought the point to light & my efforts to explain the pros & cons has served that purpose

Kurt


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## kurtak (Jan 26, 2017)

Lou said:


> Geo said:
> 
> 
> > I forgot to add, if you are melting by torch, there will be some contamination. Even if you start with chemically pure gold, if you melt it with a torch with a copper tip, it will have copper contamination. It may not be much but when you are talking about purity, it doesn't take much. Borax will soak up that small amount of copper contamination.
> ...



Yes - Harold often made mention of the fact that your torch tip can be a source of contaminating you gold - especially if you don't keep your torch tip "clean" & well maintained 

But - (assuming you are keeping your torch tip clean & well maintained) how much contamination are we talking about here

I mean - lets say you have 100 gram of 9995 gold (so "about" 3 ozt) is enough copper going to come of your torch tip to effectively reduce that 9995 gold to 998 gold (so from better the 3 nine to less then 3 nine)

I ask because that would represent 1.5 tenths of a gram of copper in such a melt - that seems like a lot of copper coming off the (clean) torch tip during such a melt

I understand that for a refiner that works for clients that "call for" gold of 4 - 6 nines special precautions &/or techniques are required to insure the purity meets what the client calls for --- but is enough copper going to come off a "clean" torch tip to reduce the purity of the small &/or hobby refiner such that it reduces the purity that it is going to effects their pay out when they go to sell their gold ??? 

Kurt


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## denmark1982 (Jan 26, 2017)

kurtak said:


> Geo said:
> 
> 
> > Even though it's possible and some people do it that way, it is recommended that you glaze a melting dish to torch melt gold.
> ...




am will use this kit http://www.ebay.com/itm/4pcs-Casting-Kit-Tongs-Quartz-Silica-Melting-Dish-Ingot-Mold-Graphite-Crucible-/252208978089?hash=item3ab8d398a9:g:FYAAAOSwfZ1WZ5z2


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## Geo (Jan 26, 2017)

Kurt, technique can also cause contamination when using a torch. Even if the torch is new. If you move the torch too close to the melt, the heat from the melt and the blow back from the torch can cause oxidation of the copper tip. Also, what ever you use to pick the dish up with (tongs, pliers), if you put anything over the lip of the dish, and especially while the flame is still on the gold, will cause contamination.
We are talking about maybe mg's at best and it only matters if you are melting relatively pure gold. If your gold is .9990 starting out and the torch causes .0002g of contamination, you still wind up with less than .999 gold. For most, this is not enough to worry about. Borax will absorb that much contamination and maybe more. 
So using good work practices and good hygiene will improve your quality of work and you can produce a great product and still cause contamination in the end of it at the melt. Borax is sort of a safety net to keep your gold as pure as it can be after the melt. Personally, I don't think it's misinformation telling people they need to use borax in the melt. As a matter of fact, the opposite might be true, IMO.
Eventually, it will make it to youtube where someone says "hey, you don't need to use borax when you melt gold" and then we get a big influx of newcomers wanting to know why they keep getting contamination after the melt. I think it should be common practice to instruct all newbies to use borax and then explain the correct way to use it.


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## Lou (Jan 26, 2017)

kurtak said:


> Lou said:
> 
> 
> > Geo said:
> ...




At many small clients I consult for that are melting small lots and refining on an output basis, not a fire assay basis/sum, their tips are often quite purple and not very clean. Soda ash from cleaning the dishes is a big offender. 

Although I torch melt gold (up to about 50 oz with a rose bud). But if you ask whether or not melting with a clean torch tip will affect the purity and payout--I doubt it. A dirty torch tip can easily knock something down from 99,95 to 99,92. 

Melting should be a purifying operation. Very high purity gold doesn't get borax.

*In my opinion, for people here, a little borax is a good thing. *


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## denmark1982 (Jan 28, 2017)

Topher_osAUrus said:


> Pure gold requires no flux.
> 
> Only a thin layer of borax glazed on the dish to capture any impurities you may have missed.
> 
> After a couple times of being in solution, and proper washing and rinsing techniques, you should have no contaminants though.




washing and rinsing techniques ehm...

and what can i use for that and how do i do that


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## Topher_osAUrus (Jan 28, 2017)

http://goldrefiningforum.com/~goldrefi/phpBB3/viewtopic.php?t=325


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## denmark1982 (Feb 1, 2017)

http://www.ebay.com/itm/182408232765


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## Topher_osAUrus (Feb 1, 2017)

Yes, that will work fine.

When heated it puffs up some, then becomes fluid and can run well and spread around the dish nicely.

I honestly haven't watched it, but here is a video by another member showing how to glaze your dish
http://goldrefiningforum.com/phpBB3/viewtopic.php?f=52&t=24917


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## denmark1982 (Feb 2, 2017)

Topher_osAUrus said:


> Yes, that will work fine.
> 
> When heated it puffs up some, then becomes fluid and can run well and spread around the dish nicely.
> 
> ...


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