I have recently started my home foundry, and have melted aluminum. I'm sure any of you who have done this know that aluminum is not quite satisfying enough. My foundry as it stands uses a steel bucket, a pipe/air input, charcoal, and a crucible. Is there any way to get it up to temperature for copper without ditching the charcoal and upping it to gas? I really want that to be my last resort and would like to avoid it if possible. Any help on how to get my furnace hotter, specifically from anyone who has melting copper with charcoal before would be great. Thank you
Melting Copper. Please Help
- Thread starter Kolten
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Tin Falcon
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Kolten I will differ your question to someone with foundry experience.
I am happy to see new eager folks join the forum . would you please post an introduction in the welcome section . tell us a bit about yourself your shop and your interest in model engine building. and your location. Knowing a little bit about you helps us help you.
Tin
I am happy to see new eager folks join the forum . would you please post an introduction in the welcome section . tell us a bit about yourself your shop and your interest in model engine building. and your location. Knowing a little bit about you helps us help you.
Tin
GWRdriver
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Kolten,
I'm not a foundryman either, but from what I've read, and seen at a couple of home foundries, you will need a forced draft of some kind (if you haven't already) and then the problem will be replenishing the supply of fuel at the same rate you burn it up.
I knew a fellow on a farm here in TN who did cast bronze commemorative belt buckles. His furnace was a simple unlined round pit dug into the bare ground. He introduced a gas line into the bottom of the pit on a tangent to the OD so that the flame created a swirl around the crucible. While it was being fired the pit was covered with a piece of sheet iron barn roofing. He could get a 16lb crucible of bronze up to pour temperature very quickly. I may not remember this correctly but IIRC it would take less than 15mins.
I'm not a foundryman either, but from what I've read, and seen at a couple of home foundries, you will need a forced draft of some kind (if you haven't already) and then the problem will be replenishing the supply of fuel at the same rate you burn it up.
I knew a fellow on a farm here in TN who did cast bronze commemorative belt buckles. His furnace was a simple unlined round pit dug into the bare ground. He introduced a gas line into the bottom of the pit on a tangent to the OD so that the flame created a swirl around the crucible. While it was being fired the pit was covered with a piece of sheet iron barn roofing. He could get a 16lb crucible of bronze up to pour temperature very quickly. I may not remember this correctly but IIRC it would take less than 15mins.
Tin Falcon
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Since copper was the first metal to be melted , and charcoal the first fueled used in the forge and foundry. logic would dictate that it can be done.
like gw said the first furnaces were nothing more than a hole in the ground .They were then improved by lining with clay and topped with a clay dome.
adding forced air should be easy a old shop vac with a blower port, a hair dryer with a burned out heater, a blacksmiths forge .
a good book on old time metal working,mining and smelting is De re metallica
Written by George Agrigola in the 1500s and translated from the Latin by Herbert Hoover, mining engineer and his wife , geologist. It is now in the public domain.
Tin
like gw said the first furnaces were nothing more than a hole in the ground .They were then improved by lining with clay and topped with a clay dome.
adding forced air should be easy a old shop vac with a blower port, a hair dryer with a burned out heater, a blacksmiths forge .
a good book on old time metal working,mining and smelting is De re metallica
Written by George Agrigola in the 1500s and translated from the Latin by Herbert Hoover, mining engineer and his wife , geologist. It is now in the public domain.
Tin
dnalot
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Last summer I built a small furnace that can melt 12 Lbs of aluminum in 30 min from a cold start. I made it from an old propane tank and it is heated by propane. See Michael Porter's book "Gas Burners" for complete plans. Copper I found reacts to the moisture in the air making it hard to melt properly. When Argon gas was blown into the crucible results improved but still not very good. Brass and Bronze on the other hand will melt very well especially if you use a fluxing agent to keep the air away from the melted metal. It was a learning experience and I did manage to cast two large aluminum parts for my first steam build and a bronze flywheel before winter set in. With the return of good weather I am eager to get back out and do some more casting.
OregonBill
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Kolten, I share your interest in pouring copper. I have it on my list to pour some axe heads that duplicate the one found with Oetzi, the Bronze Age Ice Man. I know it can be done with charcoal, as that is what the ancients used. Here is a link to a site on Viking bronze, that should give you some clues.
http://web.comhem.se/vikingbronze/casting.htm
You'll need a simple in-ground hearth, a set of bellows, a tuyere to feed the air to the charcoal and crucibles to hold your bronze or copper.
Here's another fabulous clip:
[ame]http://www.youtube.com/watch?v=oQRwxo1JQbY[/ame]
http://web.comhem.se/vikingbronze/casting.htm
You'll need a simple in-ground hearth, a set of bellows, a tuyere to feed the air to the charcoal and crucibles to hold your bronze or copper.
Here's another fabulous clip:
[ame]http://www.youtube.com/watch?v=oQRwxo1JQbY[/ame]
rrnutsplitter
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Kolten etal,
Copper is a very gassy metal to pour. You can degas with various things like chlorine and other very nasty chemicals. The gas can lead to a casting that looks like a "bran muffin". I had to wrestle with myself for a while before I told you this. Please be VERY careful when using chemicals of any kind. Remember, ventillationventillationventillation. They can make your life a living hell.
That said, there are two ways to keep gas out of your castings. First of all you should be using a cover flux, Glass works great for this. It melts covering the metal and keeps the air away from it. When I was a teenager and hanging around a brass foundry in Manasquan, N.J. they used to use their old beer bottles, yes industry was beer powered at one time. Try this and see how it works.
As far as your temp. goes, Tin Falcon was right about using charcoal when this first started. If you can melt iron with charcoal you can certainly melt copper with it. It sounds to me like you need more air, go right to the shop vac and see what that does. But make sure it has a waste gate on it to let some air out before it gets to the furnace if need be. But remember you will burn more charcoal and if you are using grocery store briquets STOP IT. You need to use real harwood charcoal. Thats why there is so many plans out there to make your own charcoal. Grocery store briquetts are usually 50% binder...like bentonite aka clay.
As far as what you are melting the first choice would be industry supplied metal, meaning the right alloy for the right job. The next is scrap yard furnished CLEAN copper pipe and wire. Do not melt copper electrical fittings, as a lot of these are beryllium copper and the smoke from this metal is poisonous. The same goes for old plumbing fittings, alot of them are high in lead, and if they are newer they are probably from china...need I say more?
Remember Silicon Bronze will get almost anything done you need and it is excellent to work with, very low drossing. Alum., and almost all copper alloys and copper itself is high drossing.
Health Tip: If the zinc smoke from brass, manganese bronze, et cetera bothers you, the old foundry trick is to drink milk, if nothing else at least it gets the taste out of your mouth.
Jeff Albright
Copper is a very gassy metal to pour. You can degas with various things like chlorine and other very nasty chemicals. The gas can lead to a casting that looks like a "bran muffin". I had to wrestle with myself for a while before I told you this. Please be VERY careful when using chemicals of any kind. Remember, ventillationventillationventillation. They can make your life a living hell.
That said, there are two ways to keep gas out of your castings. First of all you should be using a cover flux, Glass works great for this. It melts covering the metal and keeps the air away from it. When I was a teenager and hanging around a brass foundry in Manasquan, N.J. they used to use their old beer bottles, yes industry was beer powered at one time. Try this and see how it works.
As far as your temp. goes, Tin Falcon was right about using charcoal when this first started. If you can melt iron with charcoal you can certainly melt copper with it. It sounds to me like you need more air, go right to the shop vac and see what that does. But make sure it has a waste gate on it to let some air out before it gets to the furnace if need be. But remember you will burn more charcoal and if you are using grocery store briquets STOP IT. You need to use real harwood charcoal. Thats why there is so many plans out there to make your own charcoal. Grocery store briquetts are usually 50% binder...like bentonite aka clay.
As far as what you are melting the first choice would be industry supplied metal, meaning the right alloy for the right job. The next is scrap yard furnished CLEAN copper pipe and wire. Do not melt copper electrical fittings, as a lot of these are beryllium copper and the smoke from this metal is poisonous. The same goes for old plumbing fittings, alot of them are high in lead, and if they are newer they are probably from china...need I say more?
Remember Silicon Bronze will get almost anything done you need and it is excellent to work with, very low drossing. Alum., and almost all copper alloys and copper itself is high drossing.
Health Tip: If the zinc smoke from brass, manganese bronze, et cetera bothers you, the old foundry trick is to drink milk, if nothing else at least it gets the taste out of your mouth.
Jeff Albright
