Melting copper wire in a forge.

I

Ian Fifelski

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Oct 4, 2017
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I recently got a bunch of copper wire and I plan to use it for handle spacers and liners.

My question is, can I build a square steel 'crucible' and melt and cool it in that? Then forge to shape later? I am thinking of removable sides to help get the bar out.

Thanks
 
It will work in a rough manner, but you are better off using a ceramic crucible then pour into a form of some kind.
Dont forget to add flux...
 
Copper is tricky to melt and get good casting. When liquid it will absorb a ton of gas. This is oxygen mostly. And it releases this gas as it cools. This creates air pockets and voids in the casting. Your best bet is to melt in a clay graphite crucible and use a little borax to coat the top layer of the copper. Resist the urge to mix it as this will mix in gas. It’s said that copper and absorbe its own volume in gasses when liquid. Then when you pore the liquid into your steel mold give the copper a few seconds to cool. You want to pore it right befor it starts to solidify. Not like right befor but you want to pore it about as cold as you can. If you pore it to hot the copper will instantly cool when it hits the mold and will release the gas and make bubble in the copper as it hardens up. Melting temp of copper is right 2000° give or take a pinch.
 
I once read on here that melting copper in your forge will ruin it. I can't remember the context or who posted it. It might have had something to do with forge welding, remnant ions, or subatomic particles like quarks or leptons.
 
False. Maybe if you spilled a bunch in you forge and it was burning it off
 
Atlas Knife Company said:
I once read on here that melting copper in your forge will ruin it. I can't remember the context or who posted it. It might have had something to do with forge welding, remnant ions, or subatomic particles like quarks or leptons.
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Yep, it's the quarks that do it! *S* I had an old blacksmith tell me of a joke people used to play on other smiths, they'd throw a penny into the forge and then the guy couldn't do good forge welds and it'd drive him crazy trying to figure out why until the copper evaporated. Of course, there's darn little copper in a modern penny anyway. I have no idea if there is any truth at all in this so take it for what it's worth.
 
I've got friend that's a farrier and he will tell you the same thing about not
being able to forge weld if someone gets copper in their forge.
Ken.
 
I have heard that story since I was a kid, but never found any actual people with first hand knowledge that it makes any difference. I may have to test it with an old forge one day.

Personally, I would scrap any copper you have and use the money to buy good, SOLID, new copper sheets or bars. It takes good foundry type equipment and graphite crucibles to melt the coper metals and get a usable product.
 
You could allways just make up some bronze. That is much easier to cast. This is how I do it.
 
Tons cheaper then tin. I use Ferrosilacon in the 90% range. If you don’t want to use tin then you will need to use manganese. Tin gives it a warmer color and manganese a darker color.
 
I melt copper all the time. I only had a bad batch once in 10 years. Sure, you sometimes get voids but it is super easy to fill them.
I am not pouring castings. My copper is made into ingots using altoids tins, steel cans and even beer caps!IMG_9408.JPG
 
I got a huge box of hypertherm plasma consumables that I’m itching to ingot up.
 
That was interesting, but he had a good amount of copper molten in a coal forge right under the weld metal. That is going to directly apply copper atoms and ions to the steel.

It doesn't show that melting copper in a bladesmith's gas forge in the past will make a difference welding on a different day when there is no copper in the forge. He also states that the effect on stacked welds would likely be less.
I seriously doubt that melting copper in a forge in the past will make a damascus billet fail to weld.
 
Stacy E. Apelt - Bladesmith said:
That was interesting, but he had a good amount of copper molten in a coal forge right under the weld metal. That is going to directly apply copper atoms and ions to the steel.

It doesn't show that melting copper in a bladesmith's gas forge in the past will make a difference welding on a different day when there is no copper in the forge. He also states that the effect on stacked welds would likely be less.
I seriously doubt that melting copper in a forge in the past will make a damascus billet fail to weld.
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I totally agree. He had to basically braise the weld faces before it made any difference. I can't imagine any major issues melting copper in a gas forge. Even a broken crucible spill should be easy to clean up.
 
JTknives said:
My question is somehow related to this post although not quite. I hope someone can help me. When copper is forged, does it emit toxic vapors in any amount? I have looked on the internet and cannot find this specific information. Thanks in advance.
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Hi Vicky, welcome to bladeforums.
FYI - in general, replying to threads that are years old is considered bad form. This is called necroposting. It's better to start a new thread and post a link if you need to reference the old post.

Having said that, copper is soft enough that most smith's will forge it cold. Copper work hardens and gets softer with quenching, unlike steel so when one feels it's getting hard, heat to a cherry red and quench in water and it will be soft again.

Because of the relatively low melting temperature, it's hard to forge Copper hot without risk of melting.
 
weo said:
Hi Vicky, welcome to bladeforums.
FYI - in general, replying to threads that are years old is considered bad form. This is called necroposting. It's better to start a new thread and post a link if you need to reference the old post.

Having said that, copper is soft enough that most smith's will forge it cold. Copper work hardens and gets softer with quenching, unlike steel so when one feels it's getting hard, heat to a cherry red and quench in water and it will be soft again.

Because of the relatively low melting temperature, it's hard to forge Copper hot without risk of melting.
Click to expand...
Thank you, Weo, and my apologies for my necroposting. I am not really familiar with this kind of forum, but will definitely put this new knowledge into practice in future situations.
Your information is good news then, because the relatively low melting temperature will produce very little toxic fumes, if any, that will disperse much faster than if temperatures had to be higher.
 
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