I will be welding in some floor pans in the next few weeks, and I have a question about sealing lap welds. What is the best way to seal (procedurally, I am not looking for recommendations on which seam sealer to use) both on top and underneath? From inside the car, do I want to totally weld it up? What about the seam underneath? Also, after welding do I want to grind the welds down or leave as is?

As always, TIA,
Kevin

Hey Kevin,
Try a stitch weld 2" at every 2". Then come back and fill in the alternating 2" gaps. seam seal the bottom of the pan underneath. Are you using a Mig w/ gas ?

Did you ever get your chassis hot dipped or did you go with the POR-15 ?

That sounds like a sound plan. Is everyone else in agreement? Is this the best way to seal lap welds? BTW, John, you've got mail.

Regards, Kevin

Kevin, when you are preparing to seal from the underside use a hammer to close up any gaps. I've always used a heavy wire brush on my grinder to clean the seams first, then etching primer, then seal over that. I think the sealers mostly recommend over primer is best.

After that I also paint and then undercoat over the whole thing.