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Posted

i know that earlier avantis were gel coated and need to know if this was true for the blake cars that were painted with a different type of paint than previously used. would also be helpful to know if anyone here has actually stripped the paint from an '83 and what process was used. thank you!

Posted

My 74 does not have a gel coat nor, do I believe, does my 83. I've taken the 74 to bare glass so I'm sure about it. Bob

Posted

My '70 was not gel coated when it was stripped for painting which included a gel coat. It did, however have another color under the top coat...which I knew due to obtaining a production order.

About twelve years ago I went to look at a '67 Avanti I might have been interested in and it had the original paint. While the paint was still glossy and pretty well maintained, from certain angles you could see the body seams through the paint. It that car had been gel coated that wouldn't have been possible I don't believe.

Posted

change the wording in my original post from i "know" to i "thought" that early avantis were gel coated. as was just explained to me by a friend who has been in the fiberglass repair business for many years the "primer" that was used had a resin content that acted as a sealer for the raw fiberglass but was not what he considers a true gel coat and didn't work as well as the real thing. possibly an effort in cost savings?

Posted

I'm not sure where this discussion is leading but to answer the last question, I removed the paint from my 74 with over 100 razor blades and over 40 hours of labor. Bob

Posted

The problem with Blake's paint system was not just the paint. The new body composition required a far longer time to allow chemical agents to come to the surface of the body and evaporate than the fiberglass they had been using. Once the bodies were painted the chemicals had nowhere to go and caused the paint to bubble and come up. Blake blamed it on the paint when that wasn't the cause. Maybe the new paint was a mismatch but the paint Avanti had been using would have had the same issues.

If Blake had done a couple of pilot cars to test the new body composition and new paint out for a reasonable period of time the problem could have been identified and corrections made before full production was started. I know that's hindsight, but still...most companies try and do some testing before major changes in a product.

After all these years, I doubt if painting those bodies would have any ill effect as long as proper prep procedures are followed...gel coat or not.

Posted

The problem with Blake's paint system was not just the paint. The new body composition required a far longer time to allow chemical agents to come to the surface of the body and evaporate than the fiberglass they had been using.

I thought I'd heard the '83 paint problem had been traced to oil leaking into the compressed-air system that fed the paint guns.

Posted

That's a new one to me. I've never heard that. I'm sure that could cause a problem as well.

Posted

gunslinger, can you elaborate what was different about what blake used for body material vs what was used previously? it seems that the formulas for smc glass have changed a number of times since the 70's. my real concern is having anything "ghosting" thru the top coat because the body wasn't prepped properly for the type of glass used.

Posted

Off topic, but might be of interest to some:

Besides my weakness for old cars, I also have a soft spot for acoustic guitars. That doesn't mean I play them well, but I do appreciate a nice one. In the late 90's a small guitar company opened up in my hometown, Tacoma Guitars. They built a high quality solid wood guitar at half the price of a Martin or a Taylor. I was an instant fan and acquired about 5 of them over the years.

I even toured the factory and talked to some of the people behind these guitars, each of which was excited and proud of their product.

There was one fatal flaw in their product though, and that was the finish. Almost every one of them would eventually develop the dreaded "Tacoma Rash" and the finish would start to lift and bubble. They provided a lifetime warranty, and they refinished many guitars. Some thought it was the finish they were using, others thought it might be mosture or oil in the air lines. I don't know if anyone ever found out for sure.

The last time I talked to the managers there, they were very happy since Fender had just acquired them and they thougth they had the finish problem cured.

It wasn't long after that that Fender closed the doors and killed the brand. Part of the reason was their reputation was damaged, I'm sure, but like Blake the cost of refinishing all those guitars had the company bleeding money.

I still have 2 of the originals and they are unique and great guitars, and both have eventually developed the "rash"!

Posted

I don't remember all the particulars, but after Blake unsuccessfully sued the paint manufacturer over the problem it eventually came out that the problem was the new body composition as I had previously said. Steve Blake went to a different body manufacturing process that allowed far larger body sections to be molded with a goal of reducing man-hours in body assembly and finishing...admitted a pretty labor intensive process.

There was something in the new process which required a far longer amount of time to release oils and chemicals from the molding process to leach to the surface and evaporate. Apparently that was unknown to Blake or discounted...who knows by this time? Once the body was primed and painted the chemicals reaching the body surface had to go somewhere and the paint would bubble and lift off...sometimes insist and sometimes in sheets.

As I said before...again in hindsight...if Steve Blake had tried the new body process on a few test cars...with the old paint system and the new...and gauge the results...the problems could have been recognized and corrected before the disaster that occurred could have happened.

Steve Blake...for many improvements he instituted in Avanti Motors...was also something of a bull in a china shop. He instituted so many changes without a real plan or process...that Avanti Motors went the way it did. Whether he was a visionary...a managerial disaster...or somewhere in between is arguable and part of Avanti history.

Posted

thanks for the reply! although after 32 years one would like to think all the crap was done leaching, the safe bet will be to gel-coat the whole car and be happy.

Posted

I can't agree more. Now it's a matter of proper preparation of the body. When my '70 was painted the shop did such a great job prepping the body more than one person can't believe it's fiberglass instead of steel.

Posted

I continue to be puzzled by the term gel-coat. If I look it up the definition is a polyester or epoxy coating sprayed into the female mold prior to glass or other material being laid to create strength and thickness.

Did I gel-coat mine when I sprayed the epoxy 2K on it after scraping off the old paint and primer and sanding the surface of my 74? If so, then it's just another term for good preparation and painting procedure. If not - What am I missing???

Posted (edited)

As I understand it, gelcoat is a way of sealing rough fiberglass surfaces to keep the glass fibers from breaking/working loose from the surface, particularly after panel repairs that necessitated cutting into the panel surface, to make a tough, smooth, solid surface for the paint to adhere to.

I've not had personal experience with gelcoat, but it can be done in 2 ways: spray it as the first coat in the parts mold (after waxing the mold for hand-laid fiberglass parts) when the part is made, or spray it onto an existing bare fiberglass panel to seal it before painting. I don't think gelcoat is used in press-molded parts, only for hand-laid parts to give a smoother outer surface (since the mold is smooth, the gelcoat comes out smooth). If gelcoat is sprayed onto a fiberglass panel to seal it, it results in a somewhat rough surface and needs to be block-sanded smooth when it dries, before applying primer.

I do not think either Corvettes or Avanti's had gelcoat applied to them by the factory (their panels were press-molded).

http://www.corvetteactioncenter.com/forums/c1-and-c2-general-and-technical-discussion/44259-should-i-gelcoat-3.html

http://www.corvetteforum.com/forums/c1-and-c2-corvettes/579905-gel-coat-do-i-need-to-worry-about-it.html

Edited by WayneC
Posted

From my understanding of the process, a gelcoat has to be applied to the mold and has the first layers of fiberglass laid on top before it sets up, in order to provide a chemical and mechanical bond. The gelcoat is nothing but a thickness of pure resin. You can still gelcoat a bare Avanti body, but you'll be blocking it until the cows come home. The product used to do this is Morton's Eliminator, which is a sprayable form of resin.

Using 3-4 coats of a good K2 Epoxy primer will accomplish the same thing, followed by as many coats of sanding primer that you think will scratch your itch, before color coating and clear coating....

Posted (edited)

Close, but there's actually two very basic reasons to have that layer of gelcoat applied to the mold - isolating the fiberglass cloth/strands from the outside surface of the part, and extending the mold's lifespan by providing a a smooth non-abrasive surface against the tooling gel of the mold. There's such a difference in demolding gel and non-gelcoated products that it's even a good practice to use different mold release products and application schedules with each. The gelcoat is a polyester product very similar to the resin used in the part's construction, but with important design differences. It's more flexible than ordinary resin and can have UV inhibitors built-in, and there's different hardness grades available to suit applications from bare use on aircraft parts to intention to be primed and painted. The gelcoat has to be allowed to set up to the point where you can leave a fingerprint on it but not smear it or move it around with gentle finger pressure. That's so when the part is made there's no contact between the glass itself (whether chopper strands, glass mat wetted or glass mat dry in LRTM molds) and the mold. Resin/Glass that's been formed right up against a mold will always require much more paint prep, as the outer surface will have porosity so tiny that even a heavy primer coat will end up with a zillion teeny bubbles popping up as it dries. As expensive as gelcoat is compared to paint, it's still cheaper and better in the long run to do gelcoat in the mold than the extra prep and materials needed later on a the finished part to paint it.

Edited by GlennW
Posted

thanks for the reply! although after 32 years one would like to think all the crap was done leaching, the safe bet will be to gel-coat the whole car and be happy.

Rather than gelcoat, I'd consider Dura Tec 2 part polyester primer. Sands great, self levels better than gelcoat and uses the same MEK family catalyst. Whenever I'm developing a plug (pattern) for a new mold from fiberglass, wood, foam, etc, the last coat(s) are the duratec. You can sand it from #60 to #400 wetsand, followed by sealer and release agent to make a mold right off of it. It's similarly excellent for over a fiberglass repair, where you block it and wetsand it down per usual and then paint it with whatever primer & finish coats you'd use over a gelcoat surface.

Posted

RQB3263 Is currently in the paint shop and should get color coat and clear this week...."Diamond Blue Metallic"...After some customizing work, a complete D/A sanding of existing paint (not original).and filling and spot priming and hand sanding it got a full polyester primer and sand...when I saw it Friday it was to go into the booth for a full epoxy primer/sealer, light sanding , 3 color coats and 3 clear coats....PPG materials I believe...then clean and buff...then over to the upholstery shop next week some time ....hahaha.....this is what the "experts" here in north Florida are doing.....RQB3263

  • 2 weeks later...
Posted

We sanded and razor stripped my 1979 this summer and sealed it with a polyester type primer sealer. I found the fiberglas to be much coarser than a comparable year Corvette and also thicker.

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