Annealing copper

[homebrewed]

I bought some 1/4" OD copper tubing to make some small goose-neck LED lamps. So the tubing needs to be bent in a U. However, the tubing is pretty stiff so I'm thinking I need to anneal it. I don't think our stove can get hot enough so I'm wondering what other folks here have done to anneal work-hardened copper.

 

[benmychree]

Heat to low red and quench in water.

 

[Watchwatch]

And fill the tubes with sand


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[RJSakowski]

It doesn't take a very high temperature to anneal copper sufficiently to bend it without fracturing. There are numerous industrial references stating 700ºF. A range from 700ºF to 1200ºF is given. A higher annealing temperature will produce a softer anneal although too high a temperature increases crystal size in copper. I you have a gas stove, you should be able to get your copper hot enough to anneal it. Making a makeshift oven with brick or firebrick will help. An infrared thermometer would be good for monitoring the temperature.

I would experiment with some scrap pieces first.

 

[Dhal22]

What about a tubing bender?

 

[Liljoebrshooter]

These work good.

Joe

 

[Joeman77]

I've done with an acetylene torch by starting with a lazy smoky flame & put the copper tube in the edge of the flame to get it black and sooty, then adjust the torch so it's like what you'd use to braze & heat the copper tube up until it burns the soot off it. Don't quench it or you'll re-harden it, just let it cool slowly in the air and it'll bend nicely. Once you get the bend you want you can heat it up & quench it to Harden & set it.

 

[akjeff]

When annealing non-ferrous metals like copper and brass, it makes no difference whether you quench it or not, it'll be annealed provided you take it to a high enough temperature. I generally quench it in water, as it allows you to handle it right away.

 

[Joeman77]

When annealing non-ferrous metals like copper and brass, it makes no difference whether you quench it or not, it'll be annealed provided you take it to a high enough temperature. I generally quench it in water, as it allows you to handle it right away.

Well, thanks! I wasn't aware of that, goes to show you learn something new everyday! And it'll definitely speed up my future projects, sometimes the bigger stuff has to set for hours.

 

[homebrewed]

Thanks all for the suggestions! I do have one additional question. Some types of heat treating call for a high temperature soak. Does this apply when annealing copper? I suspect not but it's worth asking.