So I am flux welding a turbo kit.... now I am no fantastic welder by any means. I finished the welds and don't see any pinholes, but i decided to test the pipes by filling them w/ water. There is a leak somewhere because moisture creeps out around the welds. It doesn't even really drip or anything, but the presence of moisture on the outside is a clear indiciation.

Probably a stupid question, but wouldn't exhaust gas leak out the same area, if water leaks as well? Even if the water leak is only a tiny bit?

 

you probably burnt a hole into the pipe under one of the weld beads.

 

I you trying to say the weld just sits on top of the pipe and he somehow burnt a hole in the pipe under the weld that is just sitting on top?

flux core welds are notorious for "worm holes". im suprised you were even able to weld thin gauge tubing (or 1.5" sch10 piping for that matter) with FCAW with no visible flaws (if you are indeed correct that there are none)

 

ugh...so frustrating....

Am I correct to assume that these will leak exhaust pretty bad as well?

What's the best way to fix it? Just grind everything out and re weld?

 

You can make a cap just like you would for a boost leak test with a air fitting on it, cap both ends and put pressure in it. Spray with soap and water to find the leaks

 

Was the piece hot or in the sun? I just welded a gas tank and put water in it, it was out in the sun with cold water inside and there was moisture on the welds but then i realized there was moisture on the whole tank from the cool water.

like bigd said pressure test it you can even use a bike pump

 

in for pics of a flux welded turbo kit!

 

due to surface tension water needs about .003 to pass through. air will pass through somewhere in the .000X range if memory serves correct

also there will be more pressure inside the pipe than outside making matters worse.

 

Flux core is just horrible for anything involving automotive fab. Theres probably tons of small pinholes you can't see. Not to mention tons of wire sticking inside the work piece.

 

Wire sticking inside is a sign if a shi**y weldor, not flux-core itself.

 

Well, I've never not seen it... lol

 

Well I am no great welder by any means, but i defintitely do not have welding wire sticking through the inside of the pipe...

Actually most of the welds were pretty good looking, flat and consistent. However now after fixing all of these effing leaks, they don't look so hot any more. I gave up trying to grind out all of the holes and at this point, have just been hitting the spots w/ a wire wheel, turning up the power, and welding over the spots again.