I tired to melt some silver to make ingot, but failed

I tried to melt some silver and make 500gr ingot. But 2 my poruclain crucibles broke before I even melted Borax!

I decided to melt it to larger ingots, beacue in my country there is no difference between scrap silver or numismatics, jewelers will pay you the same (half the spot!).

Can I buy graphite mold and use it as crucible and let it cool in that same mold, without pouring?

 

Use alumina crucibles, porcelain won't cut it.
Not sure about using graphite moulds as crucibles, but I suspect they will just slowly oxidise away under the heat and flame.

 

What do you think about wooden mold I made, will it work?

 

if you sell it on here you wont get half the spot but at least spot if they are brand bullion compared to a lump of silver that you claim is silver and looks like silver

 

I reckon the wooden mold should work. I have seen guys use raw potatoes for a mold.

 

Wooden mould may not wont work in my opinion!

My uncle used to smelt metals and any amount of moisture can cause exploding molten metal when pouring and i have the inside glove scar to prove it ! that was from a slightly damp purpose made ingot mould! Be careful

 

OK, I give up melting.

Now, I tried to melt one bar, and now I have yellow Borax residue on it, how do I remove it without sand paper?

 

Dilute sulphuric acid (5-10%) will dissolve the borax without affecting the silver.
It will work faster if heated.

 

I wanted to try this before, seems like a lot more work than it is worth. I've also resisted the urge to take a silver round out back and hit it with a hammer to see how flat I can make it.

 

You can try puting on rail and let the train run over it, that should make it flat

 

dont count on it. Train conductor will spot that on the rail and put the skids on.
yes silver is so powerful, strong enough to stop a locomotive.
Free silver. Carry on down the line.

 

Should preheat the Porcelain crucible first.
Make sure both crucible and the mould are same temperature.

 

It broke before I even melted borax in it. So I pre heated. considering the mold: you cant preheat wooden mold

 

I guess , you might missed a step. Did you heated the porcelain then you poured your Borax?
It will sure cracked the crucible. A sudden contraction that porcelain doesn't have.

NOTE

These porcelain crucibles with lids are glazed, except where stated. They do not crack, explode or deform at temperatures up to 1050C, but are usable to 1560C

 

i would recommend the following
http://www.ebay.com.au/itm/Melting-...cal_Scientific_Equipment2&hash=item540cd9b215
the other thing to keep in mind is melting 500g is going to require a decent amount of heat to melt the silver so you might need 2 torches

 

My father is a plumber and he told me they used to pour lead joints on waste pipes. They'd keep a large pot of lead cooking on the site. Sometimes they'd mess with each other by flicking water at the lead pot causing small lead explosions. Dangerous but hey at least it was fun.

 

Melting points <url>http://www.kitco.com/jewelry/meltingpoints.html</url>

Graphite would burn over a flame.
A wooden mould would char