I am sanding a friends 67 mustang down to bare metal (6 different layers to get to metal!!!). and spraying it with epoxy primer so I can continue with the paint in the spring (working in my pole barn with no heat). I am still very much a beginner. I have read many posts on here and have watched many videos and the large majority of painters apply a high build primer and block sand out any imperfections then seal prior to applying base/clear. If you feel like you have the panels straight do you still recommend the high build and block sanding? If I skip the high build and blocking will I end up with one of those cases where it looked straight in primer but when I base/cleared it showed every imperfection? I don't want to be lazy but then again, I have read about having layers and layers and the possibility of introducing chemical or other problems from that. Also, I think I already know this answer but, can you just do high build/blocking on select panels and the others just apply the base over the epoxy?

Thanks,
Rick

Your question title doesn't match up with your post.
2k basically means 2 components are necessary in the mixing process.

To answer your question:
I would shoot a couple of coats of build primer (2k of course) and apply some guide coat, then block sand to remove the guide coat. It is the absolute best insurance against surprises when shooting your color.

You can not tell how straight a panel is (or is not) until you sand with a guide coat or get it all buffed out.

Question is, when would you rather find out?

BeoBob wrote:You can not tell how straight a panel is (or is not) until you sand with a guide coat or get it all buffed out.

Question is, when would you rather find out?

That is the best explanation I've ever seen.
Well said!!!

high fill wont take out many imperfections, its still primer and can only be used to a certain thickness.
a skim coat of filler and block that out is better than thick primer any day of the week for a lasting fininsh (imo anyways), or you can use spray polyester, its basically filler that you spray on, easy to sand and can put it on thick with no problems, trouble is, its expensive
always use a guide coat when blocking
krem

Thanks guys. You have convinced me that I need to go ahead with the high build and block sanding with guide coat. Also, thanks for the clarification on the term 2K.
Rick