Melting flakes
- Thread starter Varts
- Start date
Help Support Prospecting Australia:
- Joined
- Mar 23, 2013
- Messages
- 806
- Reaction score
- 272
Propane wont get hot enough, get the yellow mapp gas canisters . They contain acetylene.
DD
DD
Hi Varts,
I haven't melted gold myself however I can tell you that you will struggle to get a air propane torch get hot enough to melt gold. You would be better off with a oxy propane torch or oxy acetylene torch, since gold will not oxidise it may be better off to use a slightly oxidising flame and use a flux. I had a recipe for a flux made from NaNO3, Borax (Boric acid), NaCO3 and SiO2. The flux will oxidise most of the impurities out of the gold.
The other option is to use an electric arc to melt the gold. This can be done with a welding power supply and carbon rods, I probably wouldn't recommend it though because it's hard to control and slightly unsafe.
I wouldn't use a stainless steel spoon. Even though gold will melt first the spoon will be very soft at that temperature and there's a chance that other low melting point elements in the spoon will be pulled into the gold and alloying or vice versa. You'd be better off investing in a crucible. You could however use stainless steel as a casting mold since it'll only be hot for a relatively short time.
I build a furnace a year or so ago that burnt charcoal or coal and had a heat gun blowing air in. That worked well with lead and aluminum but it wasn't quite hot enough to consistently handle copper which has a similar melting point to gold. Depended on the fuel used and the volume of air being blown in to get the temp up high enough. You could maybe build something like that but a little better in design so it melts gold.
Some food for thought anyway.
Regards,
Alex
I haven't melted gold myself however I can tell you that you will struggle to get a air propane torch get hot enough to melt gold. You would be better off with a oxy propane torch or oxy acetylene torch, since gold will not oxidise it may be better off to use a slightly oxidising flame and use a flux. I had a recipe for a flux made from NaNO3, Borax (Boric acid), NaCO3 and SiO2. The flux will oxidise most of the impurities out of the gold.
The other option is to use an electric arc to melt the gold. This can be done with a welding power supply and carbon rods, I probably wouldn't recommend it though because it's hard to control and slightly unsafe.
I wouldn't use a stainless steel spoon. Even though gold will melt first the spoon will be very soft at that temperature and there's a chance that other low melting point elements in the spoon will be pulled into the gold and alloying or vice versa. You'd be better off investing in a crucible. You could however use stainless steel as a casting mold since it'll only be hot for a relatively short time.
I build a furnace a year or so ago that burnt charcoal or coal and had a heat gun blowing air in. That worked well with lead and aluminum but it wasn't quite hot enough to consistently handle copper which has a similar melting point to gold. Depended on the fuel used and the volume of air being blown in to get the temp up high enough. You could maybe build something like that but a little better in design so it melts gold.
Some food for thought anyway.
Regards,
Alex
garnethawkins
kinda obvious wouldn't ya say?
- Joined
- May 8, 2013
- Messages
- 295
- Reaction score
- 60
As the other guys said, propane just doesn't have the temp requirements to melt gold, and to be honest its a good thing, if the flakes had of melted, they would have fuzed to the spoon permanently...
Learned both those things the hard way 8.(
best bet grab ya self a mapgas pro burner from bunnings and a cheap crucibal from fleabay, also grab some borax to mix with the flakes, will stop the flakes from flying out of the crucibal from the pressure of the map gas, learned THAT the hard way too lol
Learned both those things the hard way 8.(
best bet grab ya self a mapgas pro burner from bunnings and a cheap crucibal from fleabay, also grab some borax to mix with the flakes, will stop the flakes from flying out of the crucibal from the pressure of the map gas, learned THAT the hard way too lol
yep ive tried this myself, youtube has heaps of guys burning their gold off gold chains etc with propane but it cant be ive tried it, never gets hot enough. Mapgas is the go and borax you can get them both from bunnings
I have done a few small melts with a small propane torch that i got from bunnings(thaught it was mapp at the time). The thing is not all the torches will burn hot enough for a melt.
I also use a crucible and borax.
The small torch i have has been able to melt 3.5g of dust and a few smaller 1.5g buttons from dust. The way i did it was to slowly heat the crucible(very slowly unless you want to crack it) then sprinkle borax over all surfaces of the crucible and apply heat until the borax has melted.Then turn the heat up and get the crucible red hot. I had my gold close by (but not near the flame) in a glass vial so it was slightly warm by this time. I added as much borax as gold i was going to melt then pored my gold dust on top. Then i heated, making sure to keep most heat on the gold but also keeping the rest of the crucible red hot. Slowly you will see the gold go from red hot to molten, keep heating for a bit before you try to pour though. My little torch was just hot enough to get the gold to melting point, but was a pain to pour.
I also use a crucible and borax.
The small torch i have has been able to melt 3.5g of dust and a few smaller 1.5g buttons from dust. The way i did it was to slowly heat the crucible(very slowly unless you want to crack it) then sprinkle borax over all surfaces of the crucible and apply heat until the borax has melted.Then turn the heat up and get the crucible red hot. I had my gold close by (but not near the flame) in a glass vial so it was slightly warm by this time. I added as much borax as gold i was going to melt then pored my gold dust on top. Then i heated, making sure to keep most heat on the gold but also keeping the rest of the crucible red hot. Slowly you will see the gold go from red hot to molten, keep heating for a bit before you try to pour though. My little torch was just hot enough to get the gold to melting point, but was a pain to pour.
you can get some borax and stick a small ammount on a block of blue stone and then stick your gold on top of the borax and melt it that way but be outside when doing it
