I am currently taking my 51 chevy truck to bare metal. It has epoxy primer sprayed over an old 1980s paint job. This stuff is tough and I have been removing it with a wire wheel and those funky looking black wheels which are made out of silicone I believe. I also use 80 grit on a sander when possible. I have been trying to go over all areas that I remove paint from with 80 grit but some areas like those around windshield or difficult. I am going to spray with ********** epoxy and my question is " Does the Bare metal need to be sanded with 80 grit for proper Adhesion? Thanks Clark

Your answer is on the ********** tech sheet. You'll need to familiarize yourself with a TDS when in this business.

Epoxy requires scratch for good adhesion.
Running over the metal with 80 grit on a DA is ideal but not always possible. I would be sure to go over any wire wheel work with 80 grit even if you have to do it by hand. Doesn't take much effort to put scratches in clean metal.

As for stripping the old paint, I find multiple layers come off pretty easy with a heat gun and razor blade. (See my post 1962 Chevy in projects section). You can also use much heavier grit paper on your sander for stripping the paint and then just go over the surface with 80 on a DA to prep it.

The Epoxy will adhere to any good scratch you can produce it just gets a better grip with the coarser grits.

And yes, you should read the TDS on every product you use.

Thanks for the great answers. I had never heard of a TDS but I went to the ********** website and there it was saying bare metal and aluminum should be sanded with 80 grit.

35ford wrote:Thanks for the great answers. I had never heard of a TDS but I went to the ********** website and there it was saying bare metal and aluminum should be sanded with 80 grit.

A TDS is going to be your go-to info for any particular coating or material. It may vary not only between types of material but between different brands of the same material. An example would be a primer I use for an impregnated stainless steel coating requires bare metal to 36 grit scratches minimum with the preference using alox media blast. The auto primer I'd use only needs 80 grit on bare metal. Both primers going to bare metal but the application and type of coating matter. You'll also find tech sheets on filler, hardeners, reducers, etc.

all good posts above for you or anyone else reading this ALLWAYS get the TDS sheet with any materials you get.
Jay D.