Qn: What size tip is recommended for doing general frame work?
Ans: Sorry, can't remember the number, but it's a pretty small one. Oxy-acetylene flames are VERY hot, so you can easily overheat the tubes and weaken them.

A related tip: the brass will go to hotter parts of the joint - keep the flame slightly ahead of where you want the next bit of brass to go, and keep the job turned so the brass doesn't all flow down hill if you're doing fillet brazing (with no lugs)
I've also found it useful, when brazing two pieces of different weights, to turn the flame to heat the thick piece more, and even to shade the thin piece with the rod for a few seconds to stop it overheating while the thick piece warms up.
Practice makes perfect yes, but brass is quite forgiving - you always know when your joint is good and when it isn't.


Thursday, 29 January 2009