Need Gel Coat Help

[Michael H.]

Re: Please help... Why would you want to gel coat.

John,

No one that I know is "looking down their noses" at people that prepare/restore their car in a different or better way than it was when new. If you don't want absolute dead on original, there's nothing wrong with that. Everyone has a different goal and a different opinion of what restoration is. Some of us (a minority, I'm sure) want our projects to appear as close to factory original as possible, including the flaws and typical factory production quality. It's part of the fun for a lot of us. Making them better is easy. Making them correct is far more difficult and challenging.

It's part of the evolution of accuracy in restoration. Each year, we learn more and more about how to recreate the look that a new Corvette had when sitting in the new car showroom.

I DO agree with you 100% on gelcoat for repaired areas.

[John M.]

Re: Please help... Why would you want to gel coat.

Guys,

Don't get me wrong, I love original cars! I love looking at Bowtie cars, even though I would not own one. Every one of us has things that we are willing to compromise on when it comes to originality. some of the things are a cost versus benefit issue like original tires. I would NEVER spend the money for original tires, given the small deduct for repro's. The other issues are asthetics, and everyone is willing to make the same type of decisions based on their view of the car as well. If my car was going to be a Trailer-Queen that was never to be viewed by anybody but NCRS types, I might consider putting an original style paint job on it. My cars do get driven a fair ammount, and if I am going to be driving them a lot, I want a nice looking paint job.

It is really very easy to replicate the original look to the paint. It is easy to not color-sand the orange peel away, and to not be concerned about the sanding and coverage on the finish coat. Most competent painters can fairly accurately reproduce the original appearance of factory paint, if they chose to do so. I stick with lacquer paint on judged cars since I find it very difficult to make ureathane look exactly like lacquer, but I refuse to replicate the shoddy workmanship that was evident on many of these cars.

I think that sometimes we just get a set of blinders on and think that our view of what is correct is the only view. I can't tell you how many times I have been at a local show and seen somebody checking over another person's car, and then proceed to tell them everything that is wrong with their car! Sometimes I just wonder what goes through some people's minds. It would be different if the person was asking for input on the correctness of their car, but to offer this kind input totally without being asked is incredible.

Regards, John McGraw

[Tracy C.]

shame on u Chuckdude..put your nose in the corner! *NM*

[Patrick H.]

Re: Need Gel Coat Help

Patricia,

Do you live on a gravel road? If not, then how many things are really coming up and impacting the bottom of any of your cars, much less your Corvette?

My two Corvettes (71, 72) have 128,000 and 61,000 miles on them respectively. With a little Simple Green each winter the bottoms clean up very well and after 34+ years there is no evidence of "impact damage" to the fiberglass. The "impact damage" on my 71 is on the front...where the deer hit it.

I can think of far better ways to keep the bottom of a car looking clean AND deaden sound than using undercoating. But that's just me. I suspect that after many miles of driving the bottom of your car won't look as "clean" as you'd like and may be very difficult to then repair, touch up or remove dirt.

Patrick

[Ralph Harlan]

Re: Need Gel Coat Help

As Chuck wrote, thickness is the key. Ten mils is about twice the thickness of a postage stamp. Again, as Chuck wrote, gelcoat is a polyester resin like the laminate, only more dense, so it will often start to show cracks from the effects of flexing before the laminate will be affected. Moisture protection is also a function of dry film thickness, but is in inverse proportion to the propensity of the gel to crack from flexing. To achieve a full vapor barrior effect from gelcoat, you will pile on approximately 50 - 80 mils dry film thickness; way too much for the flexibility of the laminate and vibration prone environment of a Corvette. But since you will not be floating your repair for days or months at a time, you also do not neet that degree of barrier. For what you are trying to achieve, vinylester and epoxy resins both reduce vapor transmission more effectively than polyester resins. This means that for less film thickness and less work you can seal the repair area you completed with polyester resins. You will not have to do all the sanding and prep that you would do with the gelcoat, either, although the surface will have to be clean and dry. Vinylester resin can be brushed, rolled, or sprayed, and uses MEKP as a catalyst (back to the respirator and safety goggles). Epoxy resins typically would prefer to be rolled, but can be brushed. The cost and working technique for these resins is somewhat different than the gelcoat, but one benefit is that if you want the fibers and imperfections to show thru, they will because the film thickness is much less than you will have for an effective gelcoat barrier. Color can be toned with the same pigments you would use to pigment gelcoat, but there will be much more translucency since the resins are either water clear or slightly amber without pigments. Epoxy vapor emission is slightly less hazardous than from polyester resin. I routinely use WEST epoxy from the Gougeon brothers. WEST epoxy cure times cannot be varied in the manner of polyester resins (by varying the hardener to resin ration). Temperature will be a factor with cure rate, and you can use the "fast" hardener vs the "slow" hardener. One major consideration is that while you can adhere epoxy to polyester, you cannot adhere polyester to epoxy. If you tone your epoxy black as you work it, you may decide that you do not have to undercoat after you finish - you won't be improving the barrier if you do. And while the final appearance MAY not be 100% to a purist, it will be closer than undercoat! If you pigment the polyester resin with black as you effect the repair, it will also show less.

[Chuck S.]

Jus' Tryin To Be Hep'ful To Them That Needs It... *NM*

[Patricia Brown]

Re: Jus' Tryin To Be Hep'ful To Them That Needs It

Chuck,

Thanks for your help, and you did not harangue me.

I am not dedicated to sticking with originality quite like many of you guys, but I LOVE this site because there are people who know their stuff. I've been on a couple other Corvette sites, but unless you are discussing the inner workings of an engine, there seems to be very little technical help.

Much appreciated,
Patricia