I'm going to save my notes here. Perhaps they'd be helpful to somebody else. I just went into the paint supply store and drilled them with questions. If you are in Tucson or around here, make sure to speak with Dan at KC Auto Paint & Supplies. They are AWESOME!
Little background info, I'm painting over existing factory paint job. Prepped bodywork down to a 320 Grit. Here's things I asked about and the answers I wrote down as pertains to my project:
Purpose of Guide coat? To know exactly what grit you have prepped surface to. Spray guide coat sand with say 320 to remove guide coat. After you know entire surface has been prepped to that grit. Additionally, may reveal imperfects you may want to fix with spot putty.
Purpose of high build primer? to hide deeper scratches. Say you need to sand a surface with something courser than 320 grit. You can hide say 120 grit scratches with high build. High build primer can then be sanded with say a 400 grit paper and still adhere.
If no high build primer, how to seal spot putty? can use etching primer to save myself from having to buy another primer.
Purpose of a seal coat? to hide what is behind the paint. Say you have some spot putty or even gray primer and are painting black. These things may show through the high color coat. The seal coat ensure they are hidden. Additionally, it fills in 320 grit scratches.
Max time between coats of: (1) etching primer no max time, hit surface quick with 320 grit then can paint over it.
(2) High Build Primer this would be applied second in the process if necessary. However, I'm not really using it in my project as was able to obtain 320 grit surface prep without deeper scratches. So not for sure how long you can wait in this.
(3) Seal Coat, (4) Color Coat, (5) clear coat max 48 hours to obtain chemical adhesion.
How do you use seal coat? seal coat comes before color coat. It's to provide hiding of whatever is underneath including scratches up to 320 grit (no deeper). Seal coat entire surface you are painting. I was told to use 2 coats of seal paint. Then immediately follow by color and clear. I believe you must purchase a compatible seal coat for the paint and possibly even color you are painting. I am using PPG OMNI line so I just purchased seal coat from same manufacturer.
Sanding door jams and tight radius's: use the scuff pads. They make three (or at least sold three at the store). Ultra fine, e.g. for blending into an existing clear coat. Course, for roughing up existing paint to get adhesion with new paint. Great for those radius's I need to get into. Very course, for stripping paint.
Does all shiny / clear need to be removed when painting over? I was especially interested in asking this because I spent a huge amount of time making sure any glossy finish was removed no matter how small. Dan said yes, there's no shortcut there. Gloss must be removed to ensure adhesion of new paint.
Plugging holes in body work for plastic rivets? my truck has none of rocker panel trim or running boards. However, the old rivet holes are there. I wondered if they could be closed with body filler. He said no because the body filler would crack and fall out. That those would really need welded shut. I will leave them be
Hope these things help somebody. I know I'll be looking back at them. Let me know if maybe you have some other or additional tips. As always I really appreciate your help
