[lugog]

Hi all, I am new to painting and learning on my first job. I am a perfectionist and cannot let that go. I've been spending countless hours on sanding the primer. My big problem is sanding through and I am starting to learn that better prep would have helped to prevent that also being more careful sanding. I am using high fill primer on fiberglass. I sand through and I've learned when that happens don't stop there... use the block to sand it nice and flat because most likely its a high spot. When my part was smaller I'd just reshoot the whole thing and sand again. Now that I have a larger body I am working on I shoot a small section again. I then resand the rest of it with 320 grit again just to get rid of overspray. What happens is the place I shot is fine, but then I end up sanding through on edges elsewhere usually because this is my second pass again without reshooting and its getting thin. At this point I'm going to repair a few sections - I think three small spots and then switch to 600 grit. I was going to spray some paint as a guide coat and sand that, but I am really worried of sanding through and going through another 320 600 cycle. A few questions I had...

1) Do you guide coat the 600 on primer? I could do a light pass over it but I'm sure I wouldn't get everything unless I guide coated it.

2) The guide coat color... I am painting it red as the final color. If there are any nicks I didn't fix shouldn't I use a red guide so that if anything is left it will show through less in the final paint?

3) Color sanding - many things say a contrasting color like black. Again though if there was any spot the paper couldn't reach a pinhole or what not then you've got a black spec there that you can't remove right?

4) Any tips for not sanding through?

5) I've been using a red fill primer spray can for a guid coat on the primer. I figure if I miss sanding an area then it should at least get filled in by the primer a little. But I don't know if this idea is good or bad, because shooting a guid coat that is primer seems like I have a lot more work to remove the guid. Maybe that's why I keep sanding through?

Thanks -Mike

[71haulnazz]

Dont worry about sanding through your primer. Remember that everything you do now will depict on how good your paint looks. If you sand through to fix a spot it was well worth it. Quick list of steps. Prime than do body work. Then Prime over your filler and repairs again. Then do your guide coat with a contrasting color to your primer. So you can see where you need to re fill or whatever. Then after you have sanded with your guide coat and repaired whatever, you prime again. All in all I prime as the first step, then body work, then primer again, then guide coat and fix your body work then prime again. Its a lot of work, and sanding.

[71haulnazz]

I should have been more clear, dont worry about sanding through your primer until it is your last coat. By your last coat you wont have to sand very much because all your feathering and stuff is done. Wet sanding your primer will help you not burn through so quick but it will not be a big difference maybe not at all. I sanded through my first two coats of primer to try to get out orange peel, than I redid all my bodywork that was not up to par than re primed, then did my guide coat and sand and fix, then reprimed again. Then top coat and clear. If you have any questions just searcdh this forum man, If there is a questionj for a first timer to ask I asked it and got an answer on here.

[lugog]

Thanks for the response. I'm still curious about the defects that stay in past the primer stage. In my case I'm doing a dune buggy body (manx style) and I know for the inner tub, I don't need to get every spec fixed on it as if you'd see it, but I'll probably still color sand and polish it. A guid coat might go into a divit and then not be sandable.

Here's a picture of it. I did the front end but didn't use 600 grit on the primer, just 320 and I can see some of those scratches through when you look close.