Painting over old basecoat with no remaining clearcoat?


#1

There was a previous topic about painting over old basecoat where small parts of a panel were missing the clearcoat and the basecoat had been exposed:

What if the panel, like a hood, was completely free of any old clearcoat and only the old basecoat remained? Could the hood’s old basecoat be sanded with 400 grit sandpaper and then sprayed with the new basecoat over the old basecoat? Or would you need to spray primer over the old basecoat and then spray the new basecoat over the new primer? If so, what would be the correct primer to use? Primer/sealer, etching primer, primer/filler? Thanks!


#2

Big question is how secure is the basecoat, is it sound, will it sand without going through? is it a sound base?


#3

It really depends what kind of shape the “basecoat” and your panel is in. Rock chips, scratches, peeling paint, dents and edges of left over clear are all going to play a factor in the end product. Also, what you’re trying to achieve with the repair will play a huge factor in how you approach it. If you just want it shiny again and are not too concerned with the odd wave left from breaking through, sand it, seal it and paint it and then denib and polish if you want. If you want it to look like it came off of the factory line, you’ll need to follow some best practices.

How much sanding you need to do to get a level base to work from will decide what primer you’ll need. Basecoat is very rarely hardened when applied so it will, at very least need a sealer. One or two coats of primer/sealer over a 400 grit wet can be left to dry for a day in the right temperature and then scuffed again with 600 before applying your new paint.

Hope that helps some. Good luck!


#4

I’m still out in left field with this issue as well and I see you seen my other post about this. I watched Tony’s God Father project and look at what they did to the hood of the Dodge Ram. It had major clear coat delamination and they 320ed it with the DA and then water sand with 400 and Tony shot new base right over old base. I know this was a flip job but I think this method should work fine. I put a lot of thought into this. From the videos I’ve watched so far and research I’ve done think about it. Base coat is not catalyzed. Same with the 1K primer Tony uses to spot prime areas that might get sanded through or where spot putty is. Once your foundation is ready and base is applied the 2K urethane clear is what locks it down and protects it. If you spray base over old base and don’t see a reaction while spraying I would say after the base dries and is ready for clear you are safe to lay down clear and not have an issue.

This is just what I have gathered. i could be wrong but there are a million videos of guys sanding old base, rebasing it and clearing. On my project I took Crazzed1 advice and just took my old delaminated areas down to factory primer. Applied a sealer (thinned high build 2K primer) over that and then I am going to applied new base clear over that.