Im gonna assume you are using TIG welding, looks like it. And with that, looks like a cold joint.
Looking at the separation line I can see un-fused base metal.
It wasnt welded. Looks like the base metal was heated up just enough to melt the filler onto the top of the base, no real welding going on in the joint I see.
And the tube looks dirty. Not dirty like there is crap hanging off of it. But it doesnt look like it was prepped.
For a tube I like to use scotch bright pads that are ONLY used for aluminum welding. Scuff the part up completely so you see a uniform clean (raw) aluminum surface. And some tubes will come from the foundry pretty dirty and get worse with the handling from the supplier.
You really have to clean aluminum up to a raw looking surface before you can weld it.
And next, you have to be welding. With aluminum, put the heat to it. I dont pre-heat, but some do, I dont think 1/8" wall needs pre-heat.. I just start off slow and use ALOT of current till I see the part is getting heat soaked. Then ramp it down some once the entire weldment is up to heat. And it will take some time. Aluminum will soak up some heat. But once its ALL heat soaked it will weld fast.
I think you just need a lil more time to play with it. My suggestion? Keep welding the tube. Cut off the welded parts, clean the tube and go at it again. But really put some heat to it. Then once that joint is done break it and start over. And do it again and again. It will click for you. You will find the right heat to make a weld.
Im not a teacher, but I have had to teach myself how to weld. And for me the best method was to use scrap material that I didnt care about and take it to the extreme. Yes, weld it really hot so you are blowing the metal out. Find out where the limit is. Once you are comfortable with where the metal will drop out then you know where to dial it back some.
And after you become really comfortable, and realize the base metal wont drop out with a lot of heat and more control you will be welding aluminum like its was child's play. JR
|