welding on fuel tank

[WS6]

Check it out! I didn't blow myself up.






Thanks for all your help and info everyone. It wasn't bad or scary at all. When cutting out the tank top off my LT1 tank, I had it filled with water and it flared up once. No big deal at all. Burned through a couple spots where the new panel didn't fit up to the tank as tightly as I wanted but I got those welded up in the end.

If you see anything I am doing wrong with my welding, feel free to let me know. I'm still in my early leaning phase and obviously have a ways to go before I'm good.

Thanks

[Mathius]

If you see anything I am doing wrong with my welding, feel free to let me know. I'm still in my early leaning phase and obviously have a ways to go before I'm good.

Maybe it's just a poor picture, but it looks like your welds have very little penetration at all most of the way around. I see the rolled edge that looks to me like weld sitting on top, but not burned in well. If you look in the lower right corner of the picture where the welds are located, there are a few spots where it looks like you got good penetration, but if I look straight along the bottom of the picture, I see a clearly defined line where the weld looks like a log sitting on top of the metal.

I could be wrong and it could be a bad perspective in the picture, but did you do any type of leak testing yet or any destructive tests on your previous welds?

Mathius

[WS6]

Thanks Mathius. I believe you are correct on me not getting good weld penetration. My welding has gotten better as I have progressed with this project. I actually have another thread I'd like you to look at there to if you could.

So the weld should be flatter and look like the wire has melted into the the tank and cover? I will be leak testing the welds when I put gas into it for the first time. I know this isn't proper but it will be ok. I won't be driving the car much for various reasons so it's no big deal if I didn't get it right the first time. I have done some destruction testing on my welds and they looked similar to these. The test pieces held up well but I doubt it would pass any sort of certification. At least I would hope the certifications would be more stringent. Then again, I may just be knocking myself because they were ugly welds.

If you notice the ring of obvious heat penetration around the pump ring, can you see or tell anything about the weld penetration for the welding that I did on the underside? The welds looked similar to the top ones. I think what my problem was with the tank, and I'm basing this on how I have done since then, is I was moving too fast because I was worried about burning through the tank. Could this have been my problem?

Thanks

[Mathius]

If you notice the ring of obvious heat penetration around the pump ring, can you see or tell anything about the weld penetration for the welding that I did on the underside? The welds looked similar to the top ones.

It looks like you're getting good penetration when you get the metal to burn through to the other side like that, but weld penetration and weld strength are not always the same thing. You want a nice penetration all the way to the edges of the weld without having undercut.

Undercut is hard to explain without a visual, but basically you burn into the base metal but you don't leave the puddle there long enough to fill the hole you burned.

Given that the placements of these welds aren't likely to be under a ton of structural stress other than possible gas build up in the tank, you may never have an issue with them but it's always best to do your best.

I think what my problem was with the tank, and I'm basing this on how I have done since then, is I was moving too fast because I was worried about burning through the tank. Could this have been my problem?

Thanks

It could very well have been your problem. Again, you want your weld to burn into the edges of the metal as opposed to just having a weld sit on top of it. So yeah, if you're moving too fast, you're depositing metal, but maybe not sitting there with the puddle long enough to burn in well.

And again, your welds might be ok, it might just be bad photography. But from the pictures, it looks like you have a log of weld sitting on there, instead of having good penetration.

Mathius

[WS6]

Thanks Mathius. Based on what you've just said and what I was seeing and doing with the thicker metal on my transmission tunnel, I think I was moving too fast and the metal is simply deposited or partially burnt in on the tank. I had so many issues with the new panel warping terribly that by the time I got the welding the panel onto the tank itself, I was very worried about warping the tank. I should have known that the larger amount of metal that is the tank would take the heat much better than that small panel. Live, learn,and ask questions.

Thanks