The tank on my 74 DT125 has a crack in the bottom right below the filler neck, I tried some JB weld for gas tank but it didn't work still leaks. I thought about trying to solder it but worried about gas fumes even if I flush it with water before hand. Anyone had luck fixing a similar crack?

Was that with silver solder, Simon?

I think I have it sussed... Simon says standard solder not silver solder seals steel seeps.

(Sorry, couldn't resist)

I had an AT tank leaking in the rear bottom corner, had someone TIG weld it and it's been great.

"Simon says standard solder not silver solder seals steel seeps."

Aircraftspruce.com sells a tank sealer for you guessed it, airplanes. www.aircraftspruce.com/catalog/appages/g...r.php?clickkey=11739 . Using silver solder plus this stuff will seal anything. Suprised there isnt an infomercial about this stuff.

I have a spare 69 DT 1 tank that needs repair so i'm going to try TIG with16th silicon bronze rods.
Only because there's a split on the top welded joint where it's cut away for the head stock and it needs building up a bit and reprofiling.
I think solders a good idea as very little heats required.

I’ve had a couple DT tanks repaired by the local welding shop. I figured they would braze it but he said TIG would be perfect for it. That process is very precise and not destructive. I’ve MIG welded a little on seams too which worked great. I think a problem with the repair technique is if it leaks because of rust. Super thin metal is the enemy for sure.

I agree on that.
The good thing about using solder is, providing everything is clean, you get good capillary action so better odds of getting a good seal first time and it don't come off.
TIG is good due to less heat over the use of MIG. The process is a little harder as you have to have a cloud of Argon there all the time , before, during and on completion and of course, you're feeding the rod in and keeping your arc gap as steady as possible. The result is better if you can do it or get it done for you.

thanks for the input guys, for those who have a shop weld it up did it damage the paint?