brazing problem

[supercrawlerfreak]

Ok first off this is probly my 15th tuber, so I know full well how to braze, but normally I use oxy accedline for my torch. This time I decided to try MAPP gas because it is so much cheaper than oxy accedyline. I tried brazing with the mapp and it doesnt seem to be able to get the brazing rod hot enough to let it flow on the joint. Im useing harris brasing flux and 1/16" brass brazing rod on 1/4" brake line, completely cleaned and acetoned the joints. I get the tubes cherry red and I ge tthe rod hot enough to melt to the jount, but as soon as it hits the metal it hardens again and wont flow, no matter how long I hold the torch on there.

[ecoli]

Yep, MAPP gas alone doesn't do a good job of melting those cheap brazing rods, just not quite enough heat. You need to go with a high silver content braze, like Harris safety silv 45 or 56. The high silver content lowers the melting point. Safety silv is expensive, relative to the brazing rods, but is great stuff to work with.

[FL Knifemaker]

I've never made a tube frame but I'e done a LOT of brazing and silver soldering. Have you guys tried using liquid flux?? Using a liquid flux and an acid brush gives me nice clean results. I never use map gas though only Oxy/Acetylene.

[supercrawlerfreak]

ok I found the problem, aparently you cant use the regular propane nozzel you have to use the push start one(it is set up differently) and it works like a dream now, it gets a lot hotter, because the flame is more concintrated, and the brazing rod isnt the cheap crap that you get at home depot, its the better stuff that I normally use with the oxy torch.
pics later

[Krawler Freak]

i must be lazy because i buy the ones with flux on them already.

[breitenbach14]

me too but i have the oxy/mapp set up same brand but never had that problem