TIG Brazing?

[Silverback]

Wow, I haven’t stopped by here for a little bit. Man, it looks like the forum has gone through another upgrade… anyway…

Recently I’ve seen/heard suggested using a tig torch and brazing rod as a filler to fix stuff like minor imperfections in metal work, divots, holes, rust repair…. Actually the first place that I saw it was on one of the hotrodding TV shows where they went into a bit of detail (even showing you details shot through a welding lens) using braze to fill rust pock marks left after removing a soft top off of a car. Well, it looked pretty straight forward, get the area hot and melt the brazing rod into it.

So the other day I thought I had a perfect job for this new trick, a cast steel elbow welded to some sch40 pipe (carrying air) with a few little pinhole leaks. Perfect, I’ll just melt some braze in/over the holes and get on with my life.

No such luck.

I grab some brazing rod, I grab my TIG torch, give it some pedal and POOF! It’s like a magic trick, I get a big cloud of smoke and I’m not sure where the braze went, not where I was trying to put it. I tried it a few more times, made a big mess with fine soot all over the place and went and found some normal welding rod.

Anyone know what I did wrong/how to make this work?

[tailshaft56]

Did you use flux. The tig just act as a heat source. You will still need the area fluxed ame as gas heat.

[Silverback]

Actually, no…

The only flux that I could find was the lincon electric dry powdered stuff that I didn’t exactly know how to use. Every time I’ve ever brazed something before I’ve done it at a friend’s house and he had some brush on paste like stuff or I used coated rods. How do you get the powdered stuff to stay where you want it?

Otherwise, I figured that between the shielding gas and getting the area nice and clean I could skip it (I didn’t notice any kind of flux used in the video clip), I guess I was wrong there?

[Roger]

Don't use gas brazing rod. Boiling zinc out of alloy not good for tig.
Use silicone bronze brazing rod. No flux. Can use MIG welder with this wire also.

[Rocky D]

Roger beat me to it....yep, use sil bronze, while not as strong as other wires, it will fix a lot problems. I have been successful in using TIG in sealing small holes in silver braze joints, in aircraft parts, but not for any joint initially.
When touching up a brass brazed joint, apply the heat to the bronze wire and let capillary action sweat it over to the brass. The trick in any braze operation is knowing when to quit! :D