Sheet metal removal and replacement

[Rob Wadsworth]

First piece of sheetmetal test fit! Definitely need some advice on removing the old sheetmetal. I drilled as many of the spot welds as I could and used my air chisel to work the seams apart. It was kind of crude and tedious. Some of the spot welds are difficult to find so it starts getting ugly with the air chisel....Should I be doing anything different. Grind the spot welds? Please tell me there is a better way. I have door posts, kick pans and rockers to do both sides.

I am planning to install each piece of sheetmetal one by one then put the doors back on to make sure everything aligns before final welding. Do I start tack welding at this stage or just screw together with sheetmetal screws until I test fit everything? When I do weld, how do I weld the panels together? Spot weld again? I saw a thread showing the panels welded together at the interior seem inside the engine compartment. How about the bare metal at the seams? Does the bare metal get treated before welding the seams together? Or do I just seal when I paint?

 

[fattlarry]

Two items will help alot weld through primer and a sport welder from Harbor Freight. I am just about done doing everything from the rear door posts forward and I wish I would have had the spot welder from the start. Good Luck

 

[turbotim2]

That looks familiar! I replaced all of the same panels as you are planning on, I drilled the spot welds and used a chisel. It is tedious work, you may be able to use a grinder in certain places and you will surely want to grind the metal that the new panel will be attaching to to get rid of the old spot weld bumps (for the lack of a better word). I have a pnuematic punch and flare tool (Harbor Freight) that works great for punching holes to spot weld through, its so much faster then drilling them. You can use it for flaring sheet metal for overlaps too.

 

[allenfahey]

Most body men I've worked with in the last 20 years just grind the spot welds with a wide 3/16" cut off wheel. I've only seen one body man use a spot weld drill bit. They just knock off just enough of the weld to air chisel the panel off. They then grind the rest of the weld off. Then they punch/drill holes in the new metal. Grind both mating surfaces to bare metal along with the topside of the where they will weld the new metal. Spray weld thru zinc primer on the bare metal on the mating sides. If they need to temporarily set the panel on there they use very few self tapping screws. Once it's in place they plug weld the holes. Then grind the plug weld down. They either weld the self tapping screw holes or just seal seal over top of them. Before seam sealer you have to use primer or sealer or you can/will have corrosion problems. You need to seam seal both sides. Lord Fusor 800EZ is a good seam sealer that uses a regular caulking gun. There are better 2 part seam sealers out there but you need an expensive double barrel caulking gun. That's how body men that I've worked with do it both the old and young ones.

The shop I've been at now for three years uses a 25K spot welder that is very similar to the factory spot welder. It's quicker and does a better job.