First annealment

So this thread got me thinking about a friend of mine that works as a construction foreman who is building a chain of apartment buildings.

A quick phone call and a couple days later I was knee deep in the scrap pile of one of the sites. I ended up salvaging a hundred feet of scrap wires between 3 and 10 feet of the 3-core type that is used in interior electrical, some a bit thicker, and some much larger diameter somewhere north of 4mm.

After strippimg it all with a box cutter and rolling it around a peanut butter jar, I'm left with a whole mess of neat rolls of varying lengths and thicknesses. Now I'm thinking about the next steps. I would imagine that charcoal would be a good heating agent, but I doubt my wife would be on board with me annealing copper wire in our grill. Any ideas of a nice contained way to do this without starting a grass fire or alerting nosy neighbors? Would a large metal coffee can or a paint can work for a small forge? Any tips for a safe, clean job?
 
Paint can plus a plumber's torch will work. I often use a steel plate to hold heat because copper is such a good conductor.
 
Matt B said:
So this thread got me thinking about a friend of mine that works as a construction foreman who is building a chain of apartment buildings.

A quick phone call and a couple days later I was knee deep in the scrap pile of one of the sites. I ended up salvaging a hundred feet of scrap wires between 3 and 10 feet of the 3-core type that is used in interior electrical, some a bit thicker, and some much larger diameter somewhere north of 4mm.

After strippimg it all with a box cutter and rolling it around a peanut butter jar, I'm left with a whole mess of neat rolls of varying lengths and thicknesses. Now I'm thinking about the next steps. I would imagine that charcoal would be a good heating agent, but I doubt my wife would be on board with me annealing copper wire in our grill. Any ideas of a nice contained way to do this without starting a grass fire or alerting nosy neighbors? Would a large metal coffee can or a paint can work for a small forge? Any tips for a safe, clean job?
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Most recently I did it over a cheap metal bowl fire pit with lump hardwood charcoal. It required constant fanning to get the temperature high enough.
 
So charcoal alone won't burn hot enough to get the copper red hot? How could I make this work to where I can set a timer and come back to red hot coils that I could dig out with a stick and toss into cold water? Maybe some sort of mesh bottom on a paint can with a fan blowing air through the coals? Maybe using a lid with ventilation to retain heat?
 
I would think a torch would be great if you could focus the heat on a 5 inch patch, but based on my limited knowledge it is more of a precision tool, and would require standing over it and waving the torch over the wire, leading to uneven heating. Especially in the hands of a noob like me. Not to mention the sheer quantity of wire I have coiled... If there was some way to make it work with charcoal, I could dump several rolls in, Netflix and chill, and come back to perfectly baked wire that just needs quenching.
 
Matt B said:
I would think a torch would be great if you could focus the heat on a 5 inch patch, but based on my limited knowledge it is more of a precision tool, and would require standing over it and waving the torch over the wire, leading to uneven heating. Especially in the hands of a noob like me. Not to mention the sheer quantity of wire I have coiled... If there was some way to make it work with charcoal, I could dump several rolls in, Netflix and chill, and come back to perfectly baked wire that just needs quenching.
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I would start out with the easiest method possible and see if it works. I re-annealed some wire after removing it from a tree by throwing it on my gas grill for about 15 minutes, then air quenched it. It seemed pretty soft to me. Should be pretty easy to optimize.
 
That's a lifetime supply of copper there. You are going to be spending some time annealing that lot.
Charcoal should burn hot enough if you can get it burning well. Hot enough to cook should be hot enough to anneal wire. but you will probably need a fair sized can to generate enough heat.
Don't go away and leave the wire cooking. There is not much difference between annealing and melting. Copper cooked too long and too hot turns brittle and just breaks into pieces instead of winding nicely around the branch.
It only takes a few minutes in a good fire to anneal copper. I put a few coils in then fish those out and add some more until the batch is done or until the fire cools down and won't heat the wires enough.
I also do not quench. Just allow the copper to cool naturally and it is still just as soft. Be careful not to pick up a roll you have just done by mistake. They don't look hot but can still burn fingers for a while after coming out of the fire.
 
Charcoal certainly can be hot enough. In fact, you can overheat your wire with charcoal. It all depends on how you pile the charcoal up. I made a flat bed of charcoal briquettes, which is actually compressed briquettes of powdered coal. The bed was 3 briquettes deep, and this got hot enough to overheat thin wire, it actually started melting in spots. You want the dull red glow, not bright yellow.

Any backyard fire pit can work. The problem with metal bowls is they often wick away heat. On the ground or a brick fire pit stays hotter.

Charcoal briquettes, which are powdered coal, might burn a bit hotter than lump hardwood charcoal. They are cheaper too.
 
Leo in N E Illinois said:
The problem with metal bowls is they often wick away heat.
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This may have been my problem with using briquettes. I’m no expert, I’ve only done this 3 times. With briquettes, I had some really great wire and some rolls that didn’t get hot enough. With lump, all the rolls came out great. Although, it was more work and expense since it burns faster and sometimes more inconsistent.

Leo in N E Illinois said:
Charcoal briquettes, which are powdered coal, might burn a bit hotter than lump hardwood charcoal.
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Every grilling guide I’ve read, notes that lump burns hotter (which seems counter intuitive). However, lump can be inconsistent in quality from wood type. It also burns faster, using more, making it more costly. Especially, since it is higher priced as you noted.
 
My pal dropped off a 30 foot section of massive 4 conductor wire that has one large solid wire and 3 otber braided wire,, which each consist of 8 smaller strands, when separated, so now I am on overload on all conceivable sizes of wire that I could use for a lifetime of bonsai. :p

I dont think I will have any problem with using charcoal brickettes. I have lots left over from that big hurricane that blew up Florida and the Bahamas a couple years ago. The only problem will be the container. I don't have a patch of ground to burn up, nor would my significant other look kindly on the kind of DIY projects involving open fires, if you catch my drift. I figure some kind of metal pail or paint can with ventilation in the bottom should do, or maybe I could buy a small cheapo charcoal grill.

Thanks for the suggestions and information. I'll try to keep the thread updated with results.
 
Mike Westervelt said:
Good job, when annealing braided I do it two steps, once still braided, then pull it apart, coil and re anneal.

But.......please take the time to remove the plastic coating, the fumes are super toxic, I just lay a razor knife parallel and fillet off a strip, then it peels pretty easily.
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I am usually very conscious about this type of thing- I cut coke bottle plastic ect. I made a mistake by not stripping the wire. To me bonsai is about appreciating the world, caring for it and shaping it, so I do apologize.

for others, please strip the wire first
 
Adair M said:
I think the pros do something like wind the unannealed wire around a coffee can to make manageable spools, tie them with little bits of copper, and anneal the spools.
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I used a paint can for the first re annealed batch- is that at least semi pro
 
erich_raudebaugh said:
Looks good. I don't know if you know this, but to get the softest wire, known as 'dead soft', you have to quench it in cold water when the wire gets to the right temperature, a dull red glow that's a bit faint. However, just getting it red hot will work as long as its not too hot. This is the same basic procedure for copper and silver and gold alloys (a few others too).
I've done a lot of metalwork, so it's pretty easy by now, but with a bit of practice you'll notice a difference.
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I had trouble telling if it was done
 
I’m not positive it got hot enough on the fire, it did feel softer post burn though
 
Stripping and rolling the braided wire is a bit of a PITA. I used a box cutter like I did for the solid core, but it kept getting snagged on the braid, and when I separated the wire, getting the spiral curl out of each strand was time consuming, and it was nearly impossible to get the strands perfectly straight to get a neat coil.
 
I got around to firing up the cheapo grill with charcoal brickettes and giving it a go. I found it to be quite easy with the thin wire that I had set aside for my first attempt. I settled for a decidedly unscientific method of lighting it up and dropping several rolls of wire in a staggered pattern directly on the coals, and leaving it go for a bit, then digging them out and quenching them in a bowl of water, which I found to be oddly satisfying. After one batch of charcoal, I am left with a metric shitload of 8-foot rolls of wire that is very soft and easy to bend, and which becomes quite a bit stronger than aluminum wire of twice the diameter after the initial bend. It was a quite successful first run on thinner-diameter wire. The best part is that there was no waste,, and I didn't even dent my total supply. Next run, I will have a try with thicker wire, which will probably present more of a challenge.
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