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Re: [TCML] Source for copper hardware

Dave Leddon wrote:
I've been trying to eliminate hot spots in the primary circuit of a relatively high current (~3000 amp) drsstc by replacing high resistance connection points with copper. Even a one-inch length of 3/8-inch brass bolt can generate enough heat to melt the solder right out of a terminal lug. Which raise another interesting point, what about solder? It has ten times the resistance of copper so maybe all lugs should be crimped. I only soldered them because I don't own a crimper large enough to deal with #2 welding cable. But I digress. I've not had any success locating a source for copper nuts and bolts, probably because copper isn't strong enough to be consider a fastener, and so have been force to machine my own. I would much rather just plunk down the credit card. Does anybody know of a good source for copper hardware?

Crimping is common for applications like welding cables. Most welding supply places can crimp connectors on your cable for you.

"hard solder" (aka silver solder) or brazing is another alternative. Much higher melting point.. Hey, an excuse to use a MAPP/Oxy or Acetylene/Oxy rig! I've used one of those inexpensive MAPP/Oxy sets with the disposable bottles to do stuff.. It gets expensive if you use much gas, but for a small project, it's not too bad. MAPP/SolidOx is another possibility which is a bit less expensive for supplies.

But if you're going to do more than a simple job, it's worth getting (or renting?) a real oxy/acetylene rig, like refrigeration guys use, with the small bottles. About $300 or so, including the bottles and torch. And brazing/gas welding is actually pretty easy (compared to, say, straight stick welding) with a very small amount of practice. (as long as you stay away from aluminum.. it's just hard, because it melts before it changes color)

Have you looked at "split bolts" used in electrical wiring? They also use copper hardware for high current applications, so a commercial electrical supplier might have them.

Copper hardware is also used in the marine industries.

And, of course, McMaster Carr might have them..

But.. what you really want is exothermic welding, aka Thermite. Cad-Weld is one trade name.
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