[many birds]

As noted in my previous thread about weld thru primer, I’m in the process of installing a full quarter from AMD on my ‘75 TA. I will be using epoxy for most of it. However, in the quarter-to-roof joint will be welded.

I will be using TIG. How should I go about doing this? Fill the spot weld holes and lap weld the quarter to the roof? Fill the holes and trim the new quarter and butt weld—which will be a real PITA? Or plug weld using the holes? Or a combination of the above?

I’m not sure why the pic is sideways.

[ID67goat]

I would probably plug weld the holes and then lap weld the overlapping joint.

I am not sure Tig will add any value at this location though, might save yourself some time with Mig.

[71HOT/A]

I prefer butt welds unless you have access to a resistance welder. Overlap welds are more prone to rust between the metal if mig or tig welded. Even if you can't grind or sandblast the back side of a butt weld, you can still usually get some kind of rust preventative coating on it. Overlapped metal does not give you this option. When, not if becomes the question. I've seen some last a long time and others that failed within 1 to 2 years. Either rust creeping out of the overlapped seam or though pinholes in a bead. Sometimes the rust grows and tries to push the metal apart causing a line to bleed back in your nice shiny paint before ultimately eating through.