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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