LemansBlue68

I'm wondering if, after I strip all of the paint and complete my body repairs (mostly fixing stress cracks), if spraying the body with Eckler's spray on gelcoat is worthwhile for keeping those little errant strands of fiberglass that get freed up while sanding from popping through my new paint job. The Eckler's book on fiberglass recommends it (of course), but I've heard that the new epoxy/urethane primer/surfacers are adequate for keeping those pesky little glass fibers from popping through the new paint. I'm planning to use PPG products if that makes any difference.

JohnZ

Spray gelcoat is truly a "last resort" material, and is extremely difficult and time-consuming to sand (an understatement). The last four cars I've done were done with PPG epoxy primer and sealer, and there was nary a 'glass hair to be found anywhere.

(Had to shorten your title - if it's longer than 100 characters, nobody can respond to it).

Plastic Pig

I've only heard horror stories on the gelcoat. Never tried it

I have used PPG DP40 epoxy primer on 5 cars with no problems at all. :cheers:

wombvette

I have have used about every thing out there and all are good. Epoxy, urothane, or real gelcoat. I have done two cars with Ecklers gel coat and while it was very hard to sand, the results were very good. One of the cars was back in my shop last week and after 15 years there was no checking etc. Polyester gel coat is the vertually the same material as the fiberglass found on pre 70 Corvettes so naturally it would be very compatable. Some manufacturers of reproduction parts recomend it on their parts.

62fuelie

If the epoxy primer will do the job, it would be a lot easier. If not, there is a product called "Featherfill" that I have used successfully in the past on a 58 that had severe gelcoat damage. It is a sprayable polyester material. Pretty easy to spray, and sands fairly easily also. It does eventually get very hard.

JmpnJckFlsh

After the horror stories about how work-intensive polyester gel-coat is, I am rethinking the need for it.

PPG makes an epoxy primer in the DP40 family that is tinted like the old red oxide primer that was used at the factory (I forget the number)...that may be a good alternative to seal the fibers and lend a little authenticity where it is oversprayed. If I follow it up with a gray primer-sealer, and urethane BC/CC in Classic White, I should have a close-to-authentic, optimum paint job (roll over you lacquer purists!!!). :cheers:

TNT

Hey guys, I own a paint and body shop! The PPG DP sereis of primers are for bare metal and can be reduced and used as a sealer before you top coat with your base/clear, or your single stage color. It will not fill like a primer surfacer!!!! K36 is the work horse primer surfacer. I have refinished several vetts using K36 and it will shrink a little over about a 1 year period, depending on the exposurer to the sun. Feather fill is a polyester type of primer surfacer and usually works well if you top coat with laquer or enamel. But if you us a base/clear set up or a urethane paint the redecer will penetrate all the way through and will cause the feather fill to move [shrink] quite a bit!! The next vette i do, which is my wifes conv, I will use a primer surfacer that uses a ???MEKP I think that's the correct word, hardner. I have heard the they LOCK down great and you get even less shrinkage than K 36.. PPG has a very good sealer that you use right before you top coat, it's NCX 2005-4 depending on the color, black,white and grey, there may be other colors. ITs about 3 months old and so far is SUPER. Much better than the DP series, OH the origional DP series was pretty god but was discontinued about 2 years ago and replaced with the DPLF, lead free formula. NOT nearly as good a product. Thad LeJeune---TNT Collision Center
I usually don't like to give paint info becuase I always get a do-it yourselfer to chime in and tell how he used $125. dollars of product and got a super job. believe me, there is a difference in a 1,2, 3grand job and that 10 to 12 thousand job. :smash:

JmpnJckFlsh

Thad, what is the purpose of the primer-surfacer anyway? I thought the gelcoat was to cover and immobilize any fibers that are sticking up after repairs, and the epoxy primer would accomplish this task. Can primer-surfacer accomplish this, or is it intended to smooth the surface of minor imperfections?

Is this new catalyzed (MEKP) primer surfacer a PPG product, and if so, what is the product number? Sounds like a polyester product...MEKP is the catayst for polyester resin. Which of PPGs BC/CC products do you like the best for Corvettes?

Sorry to have so many questions, but sometimes it's hard to understand their catalogs without experience using the products.

Mac

Hey, Chuck!

My understanding is primer/surfacer is essentially a modified primer which goes on thicker and is designed to be sanded off, filling any pin holes in body filler, or at least that's what we used it for. We didn't use it as a sealer or final primer either.

A few years ago, I helped repair a Cobra kit car which had gelcoat that was brittle and horrid, but from what we could tell, it came from the manufactorer brittle and horrid. We used Eckler's gelcoat with great results.

TNT

Chuck, your getting it. Yes, the gel-coat is the factory cover for those little fibers, and yes the primer surfacer is used to true-up the surface. But K36 is not even close to the strength of gel coat. K36 is what the factory used the red and grey primer surfacers for. Now that old red oxide laquer primer surfacer can't contain those little fibers like K36 can. Now the problum with K36 and the fibers is even with a good epoxy sealer, when you put down the clear or the last coat of single stage you want it to dry kinda slow so it will flow out and have less orange peel to buff out. The hot reducer just sinks through and moves everything around a bit, and sometimes thos little fibers will show. Now on a clear-coat job if you cut and buff after about a week and then re cut and buff 12 months later you will usually get rid of the shrinkage! Here is a good set up, #1 strip the car of all paint and factory red-grey primer, being very careful not to scrape off or softn the gel coat, #2 do all repairs,either using fiberglass for cracks or bodyfiller to smooth out waves or lottle BOO-BOO areas, #3 put down 3 coats of K36, #4 let sit for 2 weeks and then dry blocksand car with 220 grit paper, #5 apply 3 more coats of K36 and let sit for 2 weeks before wet sanding car with 500 or 600 grit paper,#6 tape off car and clean with DX330 acrli-clean wax and grease remover and apply a sealer coat of DCX-2004, #7 apply enough coats of DBC base color to achieve the color. #8 after about 4hrs apply 3 wet coats of DCU 2042 clear. Enough typing and off to the shop, If you have any other Q's just ask and I'll try to help. Oh, I don't think PPG has an MEKP type of primer surfacer, A guy in another town with resto shop told me about some surfacer he uses, so when it time for me to get at it, I might check out his stuff and test it? Thad :seeya

JmpnJckFlsh

Cool, Thad, Thanks. :smash:

Just a couple more questions: (1) Is there no problem with having enough "tooth" after wet-sanding with 500-600 paper for the DCX-2004 sealer to stick, and (2) Don't all these coats of K36 eliminate the "NCRS waves" in the fiberglass? :D

TNT

Chuck, 5 or 600 paper is OK. I have used 320 with a few sand scratches show up. 400 is ok, but on the border line. My mistake, the sealer is DCU-2004. Yes, your car will look dipped, I try and stick to all the other NCRS rules but when it come to the paint, I have a breaking point! If you dull the jams and buy the team leader a nice bottle of his favorite scotch, you can get away with a small deduct for too nice of paint! Lets face it, most poeple that look at the cars on the street don't know jack about NCRS. I want men and women to say @#%$*( that car looks great!!!! I wish I could post pics on this darn boob-tube. Thad :cry

JmpnJckFlsh

Patrick, do you remember if he used Eckler's gelcoat or was it boat gelcoat?

The reason I ask is that Eckler's gelcoat has a wax mixed in the gelcoat, and after it is sprayed the wax rises to the surface to seal the gelcoat from air during the curing process. Removal of this wax during sanding is one of the frustrations of working with Eckler's gelcoat. If he sprayed two coats, it seems he would have to remove the wax before shooting the second coat if he used the Eckler's gelcoat. My understanding is that boat gelcoat has a chemical in it that accomplishes the function of the wax, and is easier to use.

lbell101

Chuck!

You are correct about the addative used. It's Duratec Clear Hi-Gloss Gel Coat Addative. It's a miracle in a can. You just add it to your NON-WAX gelcoat according to the instructions. It solves the cure problem and VASTLY reduces the orange peel problem. I will never use wax again. I don't think I'd use a gelcoat on a vette as it's alot harder to sand than the other options.