Gold Casting: Melting & Bar Creation - A Comprehensive Guide

Question
Hello,

I have recently received about 6 oz of refined gold, My question to you is how do I melt it and cast it into bars? I have read about using a torch to melt gold seems like a good way to start instead of buying a melting furnace however how do you know you are at the right temperature to pour and do you need to heat the crucible from the bottom or the top? Also is investment casting plaster or a Graphite Ingot Mold better to use to cast the bars? Do I need to use flux inside these molds as well as the crucible? I would also appreciate any guidance you can give me with this. Thank You for your time and expertise.

Jane

Answer
Hello Jane,

I apologise for my delay in response - I have been mounting a big exhibition here.

To melt your gold into bars is quite a simple process, however it also is dependent upon what you want to use your bars for once you have made them.

There is no need to use a furnace as this such a small quantity in the big scheme of things.

You will need a crucible with a crucible holder. I suggest a round one, about 12cm wide and 6~7cm tall.
You will also need a metal ingot mould, or a wire/sheet mould.
You can use either oxy-propane or oxy-acetylene to melt the metal; straight gas will not be hot enough.
Blacken the surface of the mould with a black flame....this will assist in the flow of the metal.
Heat the metal in the crucible in a circ easiest motion - this is easiest by flaming around the inside of the rim. The shape of the crucible will naturally draw the flame to the centre.
Once the metal is molten, then throw a pinch of borax onto the top and heat a bit more. The top of the metal should become shiny and bright. Now you can pour the metal in a smooth motion into the mould.
Once the metal has cooled you can remove it form the mould.
From here you can clean it in a 15% sulphuric pickle.

Hope this all makes sense.

Cheers.
* All this equipment is easily acquirable from a jewellery wholesaler supply house.
*I would avoid investment plaster and graphite....it really is a once only sort of solution and has never really been a fabulous outcome for me.