I brazed some 0.5 inch round rod, used my oxyacetylene torch. since I
did not have a regular rosebud, I used the cutting tip. It worked. Even
a number 4 welding tip was too small. Copper just sucks the heat away.

By the way, I often TIG weld 0.040 inch copper sheet, usually set the
TIG welder at 90 amps, so it would take lots of current, and probably
preheat, to weld 0.5 inch thick copper.

I like the suggestions for preheat and insulate, but I have no
experience with that approach.

richard


woodworker88 wrote:
Do you have a rosebud tip for your oxyacetylene outfit? It generally
works much better that a regular welding tip for preheating. Even if
you gas braze, you could probably preheat with the rosebud, quickly
swap tips, and fire up the actual torch tip. The rosebud that I am
familiar with is an entire section like a cutting torch attachment and
not just a tip, although they may make a tip attachment also.