Primer/Undercoat?

[austenjm90]

I've almost got all of the undercoating off the bottom of my car and my plan was to use POR-15 afterwards, but there are some corners where it has been near impossible to get every last bit off. Also stitch welding many of the seams.
So my question is what would be the best way of protecting the underside of my car? If I cant remove everything would it be better to do something like primer and then a brush on undercoating instead of POR?
Also since I'm stitch welding seams will seam sealer be needed?
Thanks

[jlevie]

Unless you ran a continuous bead, I'd think seal sealer would still be needed. Media blasting would be a good way to prep the underside. Then paint with a self etching primer followed by two coats of catalyzed urethane and finish with a thick layer of undercoat.