hardening copper wire

Sort of stupid question about hardning copper wire. I'd like to harden
some 10 guage copper wire for making an antenna.
Other than work hardening, are there any other way to harden it up? I've
been thinking about coiling it up then unwinding and recoiling a few
times. I do need it straight in the end. The jewelry people seem to think
fully annealing it coppper first is a good way to get started.
Would running it back and forth through some sort of wire straightning
jig with the ball bearings work if they're offset enough to zig-zap the
wire for the first passes before drawing it though the last times to
straight it all out?
Reply to
Cydrome Leader
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No help with hardening copper, but...
All of the fiberglass antennas I've seen inside of have a copper wire in there. The more expensive antennas usually had heavier wire. Yet even those don't take lightning strikes very well, which is why I got to see inside of them :)
Obviously I don't know what kind of application your working on but I would lean towards supporting the copper somehow...
Reply to
Leon Fisk
Just stretching it will work harden it. You could start with a heavier gauge, say 8 gauge, and pull it through a hole in a plate to reduce the diameter. You can buy the plates to do this but in your case you can just drill some holes in a steel plate. Grab a piece of 1/4 steel plate and drill two holes in it using a #32 and a #38 drill. Countersink one side of the hole and then polish the transition from the countersink to the hole with a little sandpaper. File down the end of the wire so you can stuff it through the first hole enough to get vise grips on it. Lube with lard or Crisco or motor oil or grease. Just make sure the wire is lubed for the whole length you pull through. Pull through the #32 hole first and if the wire isn't hard enough or if you think the diameter is too large pull it through the second hole. This method will give you exactly what you want, the wire will be straight and the hardness will increase quite a bit. Be sure to pull in a straight line. If you pull the wire at an angle to the plate it will tend to curl. If the wire does curl you can attach a weight to one end of the wire, attach the other end to something up high, then drop the weight. This will tend to make the wire straighten. Eric
Reply to
Work hardening is the only way. Although I am doubtful that it will get it as hard as you would like. Don't anneal that will only add to the amount of work needed.
Twist it. Put one end in a vice and chuck the other in a hand drill. Stretch it as hard as you and slowly twist it down the length. This is what the jewelers do to stiffen up pinstems after we solder them on.
It'll shorten and thicken up a little, but the cross section won't change too much.
Paul K. Dickman
Reply to
Paul K. Dickman
Just stretch it.
Reply to
Jim Wilkins
Copper wire will harden somewhat without the drawing plate. I straightened and stiffened tinned bus wire by clamping one end in a bench vise and pulling the other with pliers or Vise-Grips. When you feel the resistance become constant the wire will be straight. Doing this close over a bench keeps it from bending when you let go.
IIRC 20 AWG was the thickest I could pull without something to brace against.
Reply to
Jim Wilkins
The old knob & tube wire I removed when I rewire a former residence hardened up quite nicely when I stripped the insulation from it. The old rubber insulation adhered quite well to the tinned copper strand and I got tired of trying to get all of it off with a knife, then I discovered that if I gripped one end in the vise and stripped one pass with my utility knfe i could grip the free end in the chuck of my electric drill, put a bit of tension on the wire and pull the trigger. It only took a few seconds to generate enough heat in the wire to release the insulation cleanly and create a long straight hard copper wire.
Reply to
Workhardening works, or you can get larger gage aluminum, or copperweld (steel core, copper exterior) for better stiffness. I'd not trust hammered 10gage wire, it'll bend the first time a crow alights on it.
Reply to
How about a piece of bronze brazing rod? Check with some mobile two way radio shops. They usually have a lot of antenna wire scraps.
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