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What to use to braze copper to stainless steel?

42K views 20 replies 12 participants last post by  twophase  
#1 ·
Hey guys. Anyone have suggestions on what brazing alloys will work for brazing copper tubing to 304 stainless fittings? This is a plate heat exchanger as an r134 evaporator. Thanks in advance.
 
#2 ·
silver solder
 
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#14 ·
Also, stainless heats up at a quicker rate than copper and is easy to burn thru.
 
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#16 ·
If you do not know what to use, you likely don't know stainless soldering takes a different approach. Here is some help.

45% silver solder or better with white or brown flux to start but always point your flame at the copper allowing the ss to only get near the flame. once the solder melts onto the copper, move some heat onto the ss. And don't burn the stainless. It'll get black. Once you do, you will need to wash off your joint with cold water and do it again. Be sure your ss is clean to start with. Unlike sil-fas, you need to clean the copper & stainless with emory. Wash off harden flux with cold water and rag while the joint is still hot. Good luck.
 
#18 ·
Ok thanks for the tips.

Also, didn't know brazing rods were sold individually. I'm small time (just personal and school design projects), so I've been able to just pick up the half used rods left behind by the likes of you guys at the ice rinks I work at. I'll see what airgas has when I go to get nitro tomorrow.
 
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