Just an uneducated guess, but I recall a conversation with an expert aluminum welder where he explained how really difficult it is to repair aluminum tanks because the surface metal 'absorbs' (my word for it) impurities over the years and new repair/welding is tricky to do. Do-able, but tough even for an experienced welder.Epic fail on the plastic welding. I think I may have been more successful it would not have been a crack that was along the line of the bottom seam of the tank.
Has anybody used a bladder tank in replace of the Ronco?
I wonder if "old" plastic has similar problems?
My fabricated water tank was done with new material, of course.
Or.... it just takes a lot of practice to really nail the right temperature and prep work to do the repair you are trying for. (?)