a couple of questions

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kronix

Well-known member
Joined
Feb 24, 2012
Messages
144
hi everyone, i have a couple questions that i was hoping you could help me with..

First off, last time i melted my gold, the borax was stuck to it, making it look like crap. I talked to my local jeweler and he uses something called pickle. I researched it a bit and there is a few different solutions i can use, the one ill be going with is most likely h2so4. he had it in a slow cooker, so i bought a small one yesterday.

from what i picked up while i was watching, i know to place items in gently, i don't want hot sulfuric splashed in my eye, and that's about it.

So my questions are : has anyone had any experience with this setup, or have any better ideas?
what setting should i have it on, keep warm, low or high?
is there anything else i should know about using it this way?

thanks!
- Ian
 
ive used dilute sulfuric to remove borax before cleaning my melting dishes. it works well. ive never had it stick to my gold as i have always removed the gold while melted to another clean dry dish to cool. if you are using too much borax, you will have this problem letting the gold cool in the melting dish.it should only be enough to coat the dish. if it puddles when melted, pour off the excess while melted before melting the gold. also, keep the gold button moving a little when its cooling. this should keep the borax from sticking.
 
I boil my gold buttons in diluted sulphuric acid and it gets rid of all the borax.
And like Geo, when I'm cleaning the borax from my melting dishes, I do the same.

Take care & be safe!
Phil
 
thanks Geo.

at what ratio did you dilute it? the only sulfuric acid available to me is liquid lightning, it says "virgin sulfuric acid with 12 buffers".

also, is this stuff ok to use to make nitric in a distilling apparatus? as well as drop lead?

so to dilute it i add the water to the acid in small increments waiting for the reaction to cool before any further additions?

sorry for so many questions but i want to be sure of what im doing before i actually do it.
 
at what ratio did you dilute it?
Click to expand...
Battery acid is 35% sulphuric, that wokrs just fine.
so to dilute it i add the water to the acid in small increments waiting for the reaction to cool before any further additions?
Click to expand...
NO!!!!!! You never add water to acid , you add acid to water! If you're going to boil the diluted sulphuric in order to remove borax. there's no need to wait for it to cool.

You should do some more research before handling chemicals, so you prevent an accident.
Be safe!
Phil
 
Crap that's what I meant. The liquid lightning is 44% is that OK? And will the slow cooker get the sulfuric acid to boil? Or can I just have it on low?
 
I find boiling works best. One thing to keep in mind... as the sulfuric boils, it boils off the water and gets more concentrated. As it concentrates the boiling point climbs, It can get VERY hot and not boil if most of the water is gone so BE CAREFULL in handling at all times. It can look calm and harmless and be over 400 degrees f. Be alert and aware. Be safe.
 
sulfuric acid is nasty to work with. I prefer to pickle stuff using sodium bisulfate dissolved in hot distilled water. Make about a 10% weight/volume solution.
 
yeah i have a fused silica crucible, not a melting dish. the jeweler gave me his used one, and it already had borax in it. i also melted down a bunch of jewelry before so i had extra flux in there. i have since put it on its side and melted some of the slag out but its kinda stubborn.

i am processing about 30 lbs of blank boards with gold solder points, and some fingers on cards. i am currently about half done, as i am only working with about 2 gallons of liquid in a 5 gallon pail, so i can only process so much. i found a ceramic air stone at petsmart that isnt attacked by the AP at all so it has been working better than before, should go quicker now.

i just wanted to get all my ducks in a row before i clean/melt the powder this time around, so i can have a shiny button, not just a button.

thanks everyone, i appreciate the info.
 
Kronix, if you are concerned about purity, dont melt refined gold in a dirty dish or crucible. if it were mine, i would use some automotive battery electrolyte to boil the crucible in. it doesnt take many hours. a couple of hours of boiling should loosen the borax unless it is very contaminated. if the slag is very thick, you may use some sodium carbonate and bring it to melting. it should thin the slag so you can pour most of it out.
 
I'm pretty sure I read this on here somewhere (where else would I find information like this!).
When I did my last melt I had a metal can full of water standing by. A aluminum pop can works ok, cut the top off with scissors. As I finished the melt and removed the heat, just after the gold solidified and before the borax fused I would pluck it out of the melting dish with a set of SS forceps I have and drop it into the water.
The sudden thermal shock fractures the fused borax and most of it comes off. Any still stuck can be scraped off with a fingernail because it's pretty much powder by now.
My last melt was only 1 gram, Not sure how this would work on a larger button.
 

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