Jockey Journal Forum banner

Soldering or brazing holes in Triumph gas tank?

9K views 21 replies 17 participants last post by  Dr. Benway 
#1 ·
I've read and watched a few videos of brazing fuel tanks, but I'm wondering what the best option would be for a hole like this in this Triumph tank I have.


The tank was sandblasted and primed a few years ago, and I'm just now getting around to working on it. I'm a pretty respectable MIG weld and stick welder, but with brazing I have almost zero experience. Since the seams on this tank are already brazed, I wouldnt be able to MIG weld it anyway. I've read a few things online about soldering pinholes, and I'm kind of leaning on going that route. Anyone have experience using solder to fill holes? The tank has been empty for decades, so I'm not concerned with gas fumes or vapor. Thanks!
 
See less See more
1
#2 ·
Older H-D tanks were all soldered together. I've repaired and fix lots of leaks over the years with long term fix. It's easy to pressure test and spray soapy water to check ....
Its easy and fun ,soldering is my vote .....clean well, flex, 50/50 some blue flame and your done . File ...cool Acid flex the tanks so you can tin the tank with solder ....
 
#3 ·
Whether you solder or braze the one thing you have to remember and do. CLEAN, CLEAN, CLEAN!!! You are laying solder or brass on top of the metal. Cleanliness is vital for a good bond.
 
#4 ·
Thanks for the advice. I'm going to give soldering a try sometime this week. I can sweat copper pipes, so I'm more confident soldering then brazing, which I have almost zero experience with. After I sand or wire wheel the area to be repaired, I'm assuming I should wipe it down with something like acetone? I'm actually kind of psyched to try this out.
 
#5 ·
I think your approach is sound. Brazing requires a lot of heat that could blow out the all ready thin metal around the holes complicating the fix.
 
#6 ·
That would be hard to fix with just welding or brazing. Once you start more troubles will show up everywhere.
If you can sweat pipes you can fix your tank by soldering. Just keep in mind that you remove the acidic flux residue as good as all possible as it will cause problems down the road.
Well done this can be a long term fix. The only "real" repair would be to replace the corroded sections by tig welding in new formed sheetmetal parts.
 
#7 ·
If it is a large hole, or a large area with lots of pinholes, the antique guys will lay brass screen over the area and pour to solder to it. Gives the solder something to cling to. I have never done this myself, but have watched it being done. seemed to work OK, the tank in question is still being used but I think they POR 15 it afterward. 2 cents
 
#8 ·
every tank we did in the shop in the past 15 years with POR 15 is falling off the inside of every fuel tank - the gas we have today is not compatible with the sealer
 
#12 ·
Easy to understand how acid flux could cause future problems. Would rosin flux have different results?

My soldering experience is limited to some plumbing sweats with acid core, but plenty of electrical soldering with rosin core, never really thought about the effects of mixing the 2 {assuming the tanks were originally done with acid flux}
 
#14 ·
Nutralize any acid from soldering or brazing fluxes with TSP Trisodiumphosphate found at hardware stores. One pound box will be plenty as you'll only need a few ounces mixed with a cup of water. The rest can be used to help whiten laundry when adding an ounce or two to washer.
 
#16 ·
I've always used an oxy torch and steel filler wire. If you ever use solder or bronze, you can never do a steel repair again in that area.

I can't over-stress the need to carefully wash out the tank several times first. You can't learn by your mistakes, if a tank goes "Bang!". First mistake will be your last mistake.
 
#17 ·
I've already mig welded a patch on the bottom of the tank 4 years ago, there is definately no gas left in it :)



I'll find a used tank if I wind up chasing my tail with these holes. Until then I'm gonna try salvaging it.

Inside of the tank is pretty clean since I already did the old BB's in the tank, wrapped in a pillow and comforter, and put in the clothes drier to tumble it trick :D

Maybe I should just JB Weld the holes and seal the inside of the tank?
 
#20 ·
Thanks for the tip of using a pillow and comforter. I was putting them in the dryer and the sound was unbearable and the knocking and crashing...on my and the dents.......but it got them clean :cool:.....:D:D:D

Inside of the tank is pretty clean since I already did the old BB's in the tank, wrapped in a pillow and comforter, and put in the clothes drier to tumble it trick :D
 
#18 ·
I fixed only one bike tank but many decent repairs on rusted vintage car sheetmetal....I don't think soldier will give good results..Cut away the worst and gas or tig weld in new metal...
My recent experience with JB weld is it'll become soft in a year or two from constant fuel exposure.
 
#21 ·
Used silver solder to seal the holes up today, I'm pretty happy with how it came out and I'm confident I got a nice clean solid bond.





Afterwards I dressed it up with a file, and took the tank into a dark room with a flashlight shoved down the filler cap. I could find no light leaking through any pinholes.

I'm gonna go ahead and use some Caswell tank sealer on the inside.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top