'Virtually straight panel' and 41 year old English fiberglass auto bodies should not be in the same sentence - I'll keep up with the high build primer and block sanding until I get it right. Thanks for your help.

You know it's funny, I wasn't completely stupid as a teenager and remember Lotus fiberglass being pretty decent, panels alignment not bad, etc., back then. I think the panels just don't "age" well, not that any of the thinner fiberglass does.... yeah, Scott's dead on with the advice there.... keep working your high build, at least it's a smaller car.
Oh, and Scott, yeah, I have been talking to a few guys lately about Fiberfill at car shows. I have not tried it myself yet but I've heard good things about it. I think I'll order some the next time, and play around with it. I've been wanting to do some scratch built engine air boxes, and possibly a scratch built exotic dash. Might combo that up with doing more testing with the Tamco Universal clear.

I've had this car for 37 years - I'm now retired and restoring it. The engine cover, when closed, was initially 5/16" lower than the adjacent rear fenders on each side at the rear sides of the cover. The front cover had a similar problem, but not as bad. I filled with Evercoat Everglass then Eastwood Premium Body Filler using a 12" wide drywall knife that I filed to the correct contour to shape the area - a lot of sanding, filling, sanding. The body panels are so thin than you can't use a lot of sanding pressure as the panels oilcan. I installed gas springs to open the rear cover but had to remove them as their 45 lbs. of force distorted the panel when it was closed. On the good side, the car weighs 1550 lbs. I'm planning on PPG single stage color coat but am thinking of water borne - has anyone used water borne? They now have a water borne clear coat.

Unless you are using a proper booth set up for water, I would not suggest waterbourne. Don't get me wrong, its great stuff, but without proper conditions, water takes a fair bit of time to dry. Its much easier to control solvent based products. I am interested to see how waterboune clear stands the test of time.
I may be a bit bias, being an axalta dealer, but I have not heard good things about PPG's water system. We recently lost a shop to PPG as they joined a conglomerate and axalta won't buy into their preferred products program.. and the paint production of this shop noticeably dropped.. Even after a training seminar. There were painters looking for new jobs as their hour dived...

I have applied (2) coats of PPG MP172 black epoxy to the bare fiberglass of the engine cover and now thousands of tiny pin holes have become easily visible. Will the high build primer fill these pin holes or do I need to do something else before spraying on the high build primer?

Lotus wrote:Darrell,

I have two coats of black 2-part epoxy over the bare fiberglass then three coats of high build primer - both PPG products. I'm finding low areas after guide coating and block sanding the high build primer that are deep enough that they should probably be filled with body filler. Question - can I apply the body filler over the high build primer or do I need to go down to the black epoxy or, deeper yet, to the bare fiberglass.

Have you sanded down to the epoxy primer yet? If not you should block sand some more and stop when you start seeing the black epoxy primer. At this point you should be using a coarse grit to keep from pressing too hard on the car and flexing panels.

Plan on at least two rounds of high build and blocking to get it straight.

Front cover - applied (2) coats of black epoxy primer, waited a week then (3) coats of high build primer, waited a week then guide coat block sanded with 180 grit, then (3) more coats of high build primer - will keep block sanding using guide coat until it is flat.

Engine cover at rear of car - (2) coats of black epoxy primer applied today - this is when all of the pin holes appeared. The pin holes were evidently difficult to see on the bare fiberglass. So, do I apply (3) coats of high build primer and guide coat block sand hoping the pin holes will be filled or should I do something else for the pin holes before applying the high build primer?

It's up to you but I think I would go ahead with the high build. When blocking it down you should be able to see if they filled in.... I mean it is possible that at the bottom of the pinhole some type of contamination could be acting to "disperse" your coating. There were some early mold release products used in old open layups that could have caused that. Block down the primer well, take shop air and slowly blow down the surface, get a good light and search for them again. If you still see some of them then ( I'm betting a lot should be filled in) mix up a small batch of the high build and toothpick in what craters have shown again. Blow on a couple of coats more of the high build and you should, hopefully, get past them.

How about mixing some body filler and fill the pin holes using a razor blade as a scraper?

I'd be applying the body filler over the epoxy primer - is this OK?