QuestionPeter,
I tried melting 2.5 oz of 24K gold in a clay (white) crucible. I used a Mapp
gas torch from Home depot. The gold took about ten minutes of torch time
to melt, and I never really got a good melt- the gold refused to form into a
round pool, some of it stayed up on the side of the crucible.
After it cooled, I had to pry it out of the crucible, and some of the crucible
stuck to the gold. What a mess. I managed to get most of the material off by
tapping the gold ball. How do I get a better melt, and clean the material out
of the gold? Are graphite crucibles better? What happens to flux if you add it
to the metal? Thank you very much.
AnswerGreetings,
There are a couple of basic things that you need to address.
Firstly, I dont know what a Mapp torch is - they arent used in Australia - but your description tels me that you didnt have enough heat. You need to use an Oxy-propane torch or Oxy-acetylene torch which wil deliver enough heat quickly.
Also you need to melt a flux onto the crucible, the easiest being borax powder, which you can ususally get from a chemist.
With enough heat the metal will act in a cohesive manner and create an even button - rather than the adhesive description that you give.
WHen the button is molten you can pour it into a mould or alternatively you can allow the button to set in the crucible and then with mild heat the flux wil relaease the buttoon which can be cleaned in a 15% sulphuric acid solution.
With enough heat you will have a solid button and the only flux attcahed will on the surface.
Hope that helps.
Cheers, P
