As of today, car is expoyied and built up with high build primer. PPG products. I usually search search, but it wasn't working well on the old board. I have a couple questions.

Can filler be applied to a high build primer? OR does the high build need to be sanded down to epoxy and then filler applied, then high build?

Dura-block sanding blocks are great. However, in making a panel perfectly straight, I have slightly gone though the high build to the epoxy. I have not however gone into the metal. Is this a problem? The epoxy is dark grey and the high build is light grey. Will this create a color problem when I lay the base? Do I need to lift the entire panel a little bit with the high build?

Thanks for the help!

TTT