Copper Smelting

Re a discussion in a previous thread about UK copper coins pre '91 being 97% copper etc, i just thought i'd compile some info and link under it's own header for easy access and so on.

I'm no expert and this is all speculative - i accept no responsibility for accidents etc

Firstly, it's illegal to melt currency, so we shall not be doing that obviously

But we all come across scraps at times, and may want to melt them into billets and such.

Copper melts at about 1080 celcius according to this link

Melting Points of various metals

Which is lower than iron and steel, so a blow torch and a ladle may work.

Personally i'm unsure what it would be best to pour the resulting molten copper into to form the shape etc, presuming one does not have professional equipment/moulds - i'd be interested to know what ideas other folks here have, but from watching some vids it appears that you do not need to cool the metal slowly after smelting it - just tipping it out of the mould into cold water seems fine.

Would fine wet sand/earth work? either one or the other or possibly mixed???

Perhaps an air dried clay mould/pot???

Perhaps a glazed clay pot that has been fired and finished etc etc???

You could also make a furnace to melt it in.. i've seen furnaces made of a barbeque with air added via a hairdryer (various methods to do this), but then what to use as a crucible? and the question of what to use as a mould remains.

There are lots of YT vids on the subject, this one was a decent watch but does not answer all the questions:



some almost helpful links on crucibles:

eHow - How to Make a Crucible

Homemade Ceramic Crucible

Any ideas and contribution will be gratefully recieved!

That's really interesting, I followed the youtube link and found one for Bronze, could make axes and swords at home. 

I wonder if it is possible to melt glass in this way? casting some shapes to knap would be really interesting.

Grendel wrote:
I wonder if it is possible to melt glass in this way? casting some shapes to knap would be really interesting.

From my "bits and bobs" post in crafts..

You can absolutely make multi coloured glass blanks for knapping though, there is a thread on PP where Paleoarts uses some.... and up untill recently i used to work with a lot of glass makers and had some convos on the subject.  The issue would be that some glasses have different densities which may mean you get unpredictable fractures etc in multi coloured slabs but an expert would be able to choose glass accordingly, and they could even be moulded to shape a-la FOG blanks etc in lozenge shape with bevels etc

It would be a pain to make them without a kiln/lehr though, as you need to cool them very slowly otherwise they would crack.

ETA: i used to work with some bronze casters too and learned a little about it, you could do it at home in sand/earth moulds and presumably in stone and clay too, just like bronze age folk did

Whatever you do in metal casting make danmed sure there is NO WATER present at all! pre-heat everything especially when working with bronze or copper.  
Even a little steam from mould will spit moulten metal in your face.

Good advice!  You could seriously injure yourself very easily doing this

ETA: when i have seen bronze casters make sand/earth moulds in clamped frames, they dust the inside of the impression they make for the casting with a white powder, this would be worth looking up.  But any attempt done with a clay mould, bronze age style would find plenty of info on doing this on the net, enough folk are doing it and writing about it.

True, the powder is talcum powder, I use regular off the shelf scented talc for cuttlefish bone casting, very good, dry and quick moulds for small pieces, it will take the heat of most metals but I use pewter the most as my blowtorch is rubbish.

In this case i'm not sure it was talc... they did say what it was, and while i dont recall what they said i'm certain i would have remembered plain talc - although it may have been broadly similar or just had a posh alternative name.