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Last night I was able to completly strip down to the bare fiberglass one of the doors on my 54 Corvette. Looking at the surface of the bare fiberglass, the surface appears to have tiny cracks or "crazing" similar to what we may seen on well used china that has been through the dishwasher one too many times. I cannot detect the cracks when I run my fingernail across the surface but you can still see them under the finish. Is this to be expected and will it affect the final finish?
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Re: Bare Fiberglass Surface Condition
Probably the gel coat has cracked. My recommendation is to re-gel coat before painting, particularly on the early straight axles. There are lots of other opinions about not needing gel coat in the archives. Good luck,
Gary
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Re: Bare Fiberglass Surface Condition
Chevrolet has NEVER USED gel coat on a Corvette body.Comment
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Re: Bare Fiberglass Surface Condition
I am not certain that my car has any other applied finish over the fiberglass other than the initial red primer applied at the factory. My car has been repainted only once based on the scraping that I have done on various area of the car. Starting with the top layer of white, there is a grey primer below that, then the origional white from the factory and below it only a red primer. With all of these layers removed, I am down to the yellowish colored fiberglass. At that surface you can clearly see the fiberglass "hairs".
Now the surface over the fiberglass "hairs" is very smooth and hard and is perhaps the resins of the fiberglass processing. I think this is the layer that has the small cracks in it.
I have read several of the past postings regarding the gel-coat issue, but it seems that this layer is a "must stay" and cannot be removed. It may be that this is a typical condition and my question/advise would be an issue as to the correct primer/gel-coat/feather fill that should be used.
Lastly - maybe a dumb questions but can an area exposed to high heat ... enough to bubble the paint but not scorch (sp?)it, damage the fiberglass in any way that I should be concerned about. One of the panels on the car was somehow exposed to either a flame, garage heater or the like.
Thanks to all for your fine advise,
John L.Comment
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Re: Bare Fiberglass Surface Condition
Norris: my orignal bodied 54, vin 2184, which i stripped to bare glass in the early 70's was made of two styles of fiberglass panels. Some were yellow glass without a "coating" on their surface. the front clip and one of the door skins was coated with a soft(easily sandable) white gel-coat-like material that i'd guess was about 1/64 to 1/32 " thick. i've always referred to the white coating as gel-coat but could be wrong with the terminology. however, some of the panels on 2184 had some type of factory coating on their external surfaces. regards, mikeComment
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Re: Bare Fiberglass Surface Condition
Corvettes did not have any gelcoat used with the possible exception of 53 cars.
That being said, many people, myself included, are of the opinion that the use of gelcoat on a car which has the large ammount of crazing, like you describe, is a very wise decision. Keep in mind that Gelcoat is really nothing but polyester resin. The bodies of these cars are simply polyester resin and glass fiber mat. Gelcoat is nothing but fiberglass minus the mat. The application of gelcoat will do a very good job of consolidating the fine cracks and make them less likely to telegraph through the new paint. There are many who reccomend Slicksand, Featherfill, or a similar surfacer, but these products are also nothing but polyester resin with a large content of inert material to allow easy sanding. The fact the gelcoat is very hard to sand is one of the things that make it attractive in my opinion. It will completely seal out old repairs and prevent lacquer thinner from penetrating into any such repairs.
Regards, John McGrawComment
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Re: Bare Fiberglass Surface Condition
I agree with John. By the way there are "sandable" gel coats made. They contain talc to make them sand easier. They are and were used to make RV and semi truck tilt front end parts prior to SMC being used. They were usually grey in color. If you use gel coat, getting a product called "patch aid" will help you spray it smoother by thinning it and it will add a serfacing agent to make the gel coat dry hard. If you do not use it, the gel coat will be tacky on the surface and gum up sand paper. Another option is to quick wipe it down with Acetone after it is cured to take the tackyness away.
SteveComment
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Re: Bare Fiberglass Surface Condition
john: some of the early to mid-54 bodies had the 53 style panels. mikeComment
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Re: Bare Fiberglass Surface Condition
Mike
As I recall..my 54 #814 had 53 style glass with the exception of the doors which were made from the new metal molds.
Glass weave was evident in the fenders..the doors were smooth.Comment
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Re: Bare Fiberglass Surface Condition
Well, I got to thinkin' after I hit the post message button that NEVER was a pretty bold statement, given the fact that my personal experience is limited to 58 and newer. (unfortunately we don't have an edit capability) I have however heard the "Never" statement repeated in various forums like a fiberglass workshop I sat in on at Bloomington way back when, and the teacher then, has always been adamant, and he has or has had several 53, 54 & 55's over the years. To extend it to stuff older than 58 amounts to stating second hand information as fact, which I shouldn't have done, whether I believe it or not.
Most of my gel coat experience (all of it actually) is with boats, since I've never been an advocate of puttin' it on a Corvette. The thing about all the marine gel coats, possibly with the exception of some new generation products is, they're not intended to air dry. There are several ways that it's compensated for and some people even cover em in plastic, or spray a thin, later peelable clear coating to keep the air out. Of course when used in a mold of course the resin and glass that's laid on top of it forms an air barrier. In the case of using it over stuff that's got crazing, again, in the case of the boats it always seems to come right through in time. With today's generation of catalyst primers, some of which DO have some build characteristics to 'em, I can't see the need for a gel coat type product. As far as feather fill on a Corvette, I do have some personal experience with it, and I wouldn't put it on a lawnmower, and certainly not a Corvette. I think it's the absolute worst choice somebody can make in surface prep material. I had the unfortunate experience of buying a 63 roadster that somebody had loaded with it, that required stripping and it's the worst mess I've ever seen and the time involved was measured in weeks rather than hours. It's also very difficult to repair since it won't feather edge right either.
Anyway, I guess most people who've done it for a long time have their own ideas about what's the right way and what isn't, and it's probably about as volatile a subject as tryin' to convince a bunch of Northun' Democrats that Hillary ain't got no business back in Washington, but for my stuff gel coat and feather fill are better left to boats and (in the case of featherfill) stuff that ain't worth fixin' right.Comment
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Re: Bare Fiberglass Surface Condition
Mike,
I have 54 Corvette #068 and noticed the same condition on my car. The doors are a much smoother finish compared to the body which, even with 2 coats of paint you can still see the glass weave.
I will attempt to post a photo of the edge of the door that I am working on. The hole in the door is for the side trim clips. The fiberglass under the clip is REALLY rough.
Seems I need to research more on the beginning finishing process.
Comment
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Re: Bare Fiberglass Surface Condition
Sorry let's try the photo once moreComment
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Re: Bare Fiberglass Surface Condition
joe: your post refreshed my memmory. any of the white coated pieces on our 54(ie, 53 carryovers) were fiberglass cloth of the weave type. the non-white coated panels were random weave cloth. mikeComment
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Re: Bare Fiberglass Surface Condition
I can remember sanding the 54 car..and sanding down to primer and surfaces that were different between the fenders and the doors. It was a nice original 64,000 mile car.
It seems to me that Noland points out the introduction of the door panels being the first of the panels to be used being made from the new matched metal molds.
I think it is in his 53-62 restoration book.
I probably have pictures of the 54 door showing the smooth surface..up in the attic with the rest of the junk.Comment
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Re: Bare Fiberglass Surface Condition
I have redone 3 54's in the serial range 2000-3400. All had body panels like this:
main body - heavy white gel-coat
All inter and other panels, including rockers were non-gel coat.
Only one had any 53 panels and it was a taillight pod.Comment
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