I'm trying to solder pieces of copper together without success. I've cleaned the copper, put flux on it, tinned both pieces, put the two bits together and applied heat. The tinned area just goes black. I can solder brass OK: https://trademe.tmcdn.co.nz/photoserver/full/396620992.jpg
I have a very large electric soldering iron, and that's not hot enough. A butane blowtorch seems to be too hot. I have tried three kinds of flux. So what am I doing wrong?
johotech,
Jul 12, 7:33am
Copper is very conductive (as you probably know). For soldering big stuff, you need a lot of heat at pretty much exactly the right temperature.
Have you tried using the butane to keep the bits away from the joint area hot (without overheating), while you solder the joint with the soldering iron?
How big are the bits you are trying to join and how big is your soldering iron (watts)?
One bit is about 350x45mm and I'm trying to solder it to some similar bits. It's the sides of a gas lamp, sort of like this except about 100 years older https://trademe.tmcdn.co.nz/photoserver/full/396624695.jpg The soldering iron is big - about 10 times the size of a tiny cheap one. I suppose I could heat the iron up some more with the blowtorch.
trade4us2,
Jul 13, 5:13am
I have discovered that the solution is to NOT tin the copper before heating it. The solder will then run into the joint.
shakespeare6,
Nov 23, 8:42pm
A good solder joints an art. Use to do a hell of a lot of it every day now every other day big and small stuff , use to be fun 100 feet in the air on a crap day re- terminating a big 550 feeder on a Telco tower before the solderless type we use now, they had to be soldered and that was hard getting those joints rignt and enough heat on a windy day. Any how, get some good Flux core solder. Make sure the iron tip is clean. Tin the iron tip and work. When you apply the iron to the work to complete the joint keep the iron moving slightly and flow more solder in between the joint and the iron, the iron tip where it contacts the work needs to stay wetted to allow the heat to be transferred.
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