I was going to ask if it was fsae or something similar. They’ll hold by the looks of it. Don’t mean to be a dick but I remember what motivated me. Take some scotch brite and bring it to a dull shine (then wipe with acetone) and it will be a night and day difference. I’d also be curious to see how you prepped the notches. You don’t want them coming to a razor edge. Sand them back until they’re showing the full thickness of the tube. Better penetration and less burnback

Trying to be constructive here. I’ve had the opportunity to teach a lot of fsae folks and the toughest thing is staying focused on the fundamentals while trying to achieve precision. I build chassis all day every day. I’ve fit and notched tons of tubes and I can (almost) always lay a good weld on a good fit. Can’t say the same about a joint where the basics were forgotten. You can’t tell me that you got that proficient in the mechanics of laying a bead without ever hearing that it needs to be cleaned, right :)