In addition to the internal pressure already mentioned, it could also be that there were some contaminants inside, and they pooled/migrated to the low spot and now getting sucked into the weld puddle from within?

Aren Jenkins It probably will be fine, but since it will be at 200F+ and be subjected to plenty of vibration( the motor is bolted directly to the frame, so the whole bike shakes ) It'll likely be a re-do. The tank sits above and in front of the rear tire, and even a slight oil leak at the wrong moment, could be a disaster. Should be able to do a much better job welding it this time as well. The old one can sit on a shelf with a note on it......"Do Your Research First!" 😀

Aaron Laughlin Not something that I could really answer. All I can say is that I find value in it. 

Aaron Laughlin I would hesitate to call myself a good welder. More like functional and somewhat competent. I just suggested checking the gas flow, as just the other day I forgot to turn the gas back on, lit up the torch, and experienced the same thing, and fried the diffuser in a Furick Jazzy 10 in the process! From what I've seen, all of the coaches/instructors on here bring a lot to the table, and from a really divers background. Maybe just browse the videos, and see whose specialty most closely aligns with what you want out of welding. Though I like watching them all, as you can learn things from people who work on stuff you may never even see. Always something to learn.

Aaron Laughlin That almost sounds like the shielding gas was shut off, or had insufficient flow? I don't find this site to be much as far as a traditional forum. I mainly subscribe for the instructional video content, that may not be available on YouTube. And the instructors are pretty good about answering specific questions.

This would be a good start. https://welderskills.com/programs/jody-collier-intro-to-tig?category_id=168956

I'll stick with my usual as well. I've not seen any reviews on them that weren't from Arc-Zone. And no info at all on what sort of magic dust they're made from. 

Stickers arrived yesterday, thanks!

Nice find, that truck is in great shape. Wise move painting the frame. Try to keep the PennDOT cancer at bay for as long as possible!😀

Serious business moving heavy stuff like that, and having people around, and under it. Look forward to seeing how the repair is done.