what you are describing sounds bad, First if you are attempting to band aid a crack is something I would never consider. You need to approach from the point of replacing the entire tube or tubes. Tig welded steel frames that crack along the weld can easily be v grooved to increase the weld contact area for the filler material then build a larger than normal fillet. These will generally last longer than Tig joints in general. As for what you got going on I need to see what is going on to evaluate the repair. Just to let you know I have seen builders with 20 years in the craft screw up basic repairs because they have no clue other than how to put one together in a fixture.