Forging bronze

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skillgannon

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I made some bronze in my forge. It should be about 15% tin with a little bit of lead. Some pieces have some aluminum as well. Everything I have read said to go low heat. After the first peace started to crumble I worked the next just at dark cherry and lower. I tried 3 pieces and they all crumbled just like when i have tried copper worked to hot. Or is the problem something I am doing melting it in my forge.

Oh and now that I have done this am I going to have to re line my forge to be able to forge weld?
 
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On bronze, cherry is still too hot. Anneal by heating to the dullest red and let cool until you see no glow ... then forge. Forge it until you feel it start to stiffen as it work hardens and anneal again.

It is hard to say from the photo, but that looks pretty porous? How did you pour the ingot?

Home made brass and bronze is OK for casting, but I'm not so sure it is a good idea for forging stock.
 
Stacy E. Apelt - Bladesmith said:
On bronze, cherry is still too hot. Anneal by heating to the dullest red and let cool until you see no glow ... then forge. Forge it until you feel it start to stiffen as it work hardens and anneal again.

It is hard to say from the photo, but that looks pretty porous? How did you pour the ingot?

Home made brass and bronze is OK for casting, but I'm not so sure it is a good idea for forging stock.
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I melted the copper in a carbon mold and then added tin. I fluxed it with borax. No pouring i just let it set up in the mold.It's not too porous when I grind it. Im not not so much trying to do any hard forging but just spread it a little so I can get a couple of guards per piece. They are from 7 to 11 oz each.

So I should be at a black heat? Does it even need to be hot or do I just heat and then work until it starts to work harden?
 
Most bronze is redshort. It will crumble. Who knows what alloy you created...
Work in a very dark room and if you see it glowing, Its probably too hot.
 
Sounds like it. I thought it was supposed to be cherry.

How screwed up is my forge from running copper in it?
 
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If it is any red at all it will crumble. Cherry red is 500 degrees too hot. You can cool it to room temp berofe you start to forge it down. I usually start at black heat. Use medium blows, this isn't a place for a 6 pound sledge. A hydraulic press is great.
 
skillgannon said:
How screwed up is my forge from running carbon in it?
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Im confused, why would carbon mess up your forge. Everything we burn in forges is a carbon based fuel.
 
skillgannon said:
How screwed up is my forge from running carbon in it?
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As long as you didn't let any pour onto the lining and soak into cracks or into the pores, you should be good.

I was melting some copper in my forge using a cast iron pot and wasn't paying attention, let my forge get too hot, melted the pot and let the copper spill onto the bottom of my forge. I merely chiseled out the copper and re-cast the bottom, not the whole forge and am having no problems welding since....
I guess you'll find out the next time you try to forgeweld, eh?

JTknives said:
Im confused, why would carbon mess up your forge. Everything we burn in forges is a carbon based fuel.
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I think he meant copper.
 
Is this topic drifting ??
Fwiw, Copper harming a forge is a myth.
Of course you dont want a puddle in there, but traces of copper wont hurt anything and it wont remain as copper very long anyway as it quickly becomes a stable oxide.

We do a fair bit of decorative copper & brass to steel brazing in the forge.
 
Stacy E. Apelt - Bladesmith said:
On bronze, cherry is still too hot. Anneal by heating to the dullest red and let cool until you see no glow ... then forge. Forge it until you feel it start to stiffen as it work hardens and anneal again.

It is hard to say from the photo, but that looks pretty porous? How did you pour the ingot?

Home made brass and bronze is OK for casting, but I'm not so sure it is a good idea for forging stock.
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Depending on what OP is trying to make... I'd say just work it cold, and anneal when it begins to work-harden so he avoids tearing, just like you said. Except in very specific circumstances, and unless the metal is iron or steel, I don't forge hot.

After casting, one would need to compress the metal either by forging or by way of a rolling mill, alternating between annealing and compressing. That is, if they wanted to continue to forge it afterwards.
 
So there are a few bronze alloys that forge hot quite well. Most of the basic bronzes won't forge well at dull red or higher, but soem alloys like C95400 will hapily forge into the orange colors (and they will move like butter at these temps). I would recommend these alloys for forging. Most sil and some aluminum bronzes that I have worked with forge like a dream. Hot, they move maybe 5-10x faster than mild steel and when you cool them a bit they move like steel. So you can really knock out a bronze forging in no time flat while still getting a great finish fresh from the forge.
 
I'm just making some tiny ingots out of scrap copper and adding tin. All I'm trying to do is stretch them a bit so I can get a couple of guards out of each one
 
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