Will fiberglass ever stop "wiggling"?

[Obsessive]

I am the original owner of CSX4060, a 16 year old, fiberglass bodied car. When I did the original body work and painted the car, the body was perfectly straight and looked fantastic. However, through the years, the body has taken on a washboard like look in several areas. I first noticed it in the saddle areas between the upper fenders and the hood - see the attached picture. After a while, I noticed similar wiggling below the doors, at the gas cap recess area and even on the top of my doors.

If I block sand the car down to a straight body again and repaint it today, will the body stay straight or does fiberglass just continue to wiggle through the years? Is there a way to keep a fiberglass body looking straight?

Thanks guys.

Mike

[brettco]

It won't stay straight. When you prime and paint it it soaks up lots of solvent that slowly comes back out and causes some of the waves. That is some of the problem/ the resin also moves a lot with temperature fluctuations. Considering the originals were wavy aluminum straightened with lots of lacquer primer they had to be a mess when they were a year old. This is why I can't see putting a high dollar custom/candy paint job on a cobra/ just going to be disappoint in the long run.

[DanEC]

I don't know - yes, fiberglass does tend to move some over time, but that washboard appearance looks typical of the difficulty in color sanding the paint flat before buffing in a tight valley area. The few cars I've painted myself have some of that in the valleys. It's easy to board and stick sand flat or gentle curved areas dead flat, but in small radius valleys I have to resort to round rubber blocks, sanding pads, pieces of round swimming pool floats or what ever I can scrounge up that can conform to the curvature. But, these are usually soft surface sanding aids and it's difficult to get those areas absolutely straight and ripple free as a a result. Possibly they have always been there but you have only begun to notice them recently. You might talk to a good custom paint shop and see if they think they could sand and buff those areas again - depends on how much paint is on the car.

[Obsessive]

Originally Posted by DanEC

I don't know - yes, fiberglass does tend to move some over time, but that washboard appearance looks typical of the difficulty in color sanding the paint flat before buffing in a tight valley area. The few cars I've painted myself have some of that in the valleys. It's easy to board and stick sand flat or gentle curved areas dead flat, but in small radius valleys I have to resort to round rubber blocks, sanding pads, pieces of round swimming pool floats or what ever I can scrounge up that can conform to the curvature. But, these are usually soft surface sanding aids and it's difficult to get those areas absolutely straight and ripple free as a a result. Possibly they have always been there but you have only begun to notice them recently. You might talk to a good custom paint shop and see if they think they could sand and buff those areas again - depends on how much paint is on the car.

Thanks Dan. I wish that were the case but these areas were absolutely perfect before and after painting. For a while. The other areas of waviness were the same; perfect and wave free, now rippled. I have talked to several detailers and they all seem to agree that the paint it too thin to polish the highspots down.

[joyridin']

Is this common with Corvettes also? Maybe I never paid attention, but usually you notice a large flat door panel waving at you and I do not ever recall seeing all the older Corvettes having this problem.

How about boats? Do they have the same issue?

[Bill Bess]

I'm guessing that as time goes by, the fiberglass drys out and shrinks plus the stresses of temperature and the road cause a lot of the problem. My car was perfect 6 years ago but is now shows it's age a bit through those stresses.
Perhaps skim coating the car, and getting it perfect , plus a paint job and clear coat is the way to go...new again.
Bill

[DanEC]

Originally Posted by joyridin'

Is this common with Corvettes also? Maybe I never paid attention, but usually you notice a large flat door panel waving at you and I do not ever recall seeing all the older Corvettes having this problem.

How about boats? Do they have the same issue?

It's common on older Corvettes (C1, C2, C3) to get some random undulations in panels and print through where bulkheads, etc are bonded to the underside such as the rear of the passenger compartment tub to the rear deck. But high freqency ripples - no, not in my experience. But - orginal Corvette panels were press molded with low resin content and cured under heat. They can't be compared as apples to apples with hand-laid fiberglass bodies that are usually laid pretty resin-rich and cure without heat. Even so, I would not expect to see high frequency ripples in a quality hand-laid body over time.

[CHANMADD]

At 23 yrs old my car has a few cracks as a result of a prang, but no ripples. I do know that it was sparayed with a heavy primer coating before original paint.

[strictlypersonl]

Long-term stability has a lot to do with what resin is used, and the way it's cured. That's why we use a hybrid low-styrene resin that's primarily sold for tooling. It's more heat resistant than any type other than epoxy or urethane.

[Mother]

Wiggles in the paint happen because the material that binds the cloth into a shape shrinks. If your body is a chopped fiber body, the shrinkage happens faster. This is because of the resin used to bind the material into a shape. The best bodies are multi layer, hand laid, fiberglass bodies. They do not shrink as fast. Usually hand laid bodies resin is of a non-industrial resin. It is the resin that shrinks between the layers of fiber cloth. The fiber-glass cloth does not shrink. If you have a "Chopped" Fiber-lgass body, the ripples show up faster. Remember that it is not the body shrinking, but the resin used to bind the fiber-glass into the desired shape.

[racco]

if the car sits in the sun, the fiberglass will continue to shrink and move.

I have a 30 year old car and the glass is still showing signs of shrinkage (to the trained eye).

[Obsessive]

I appreciate all the feedback from everyone. Thank you.

The car is a very dark blue, nearly black. It definately heats up in the sun - and the FE under the hood helps heat it up too! I knew a guy with a Contemporary that showed the same rippling effect in the upper fenders and he told me that he had seen it in other Cobras. When the car was about 3-5 years old, I started to see some odd changes in the body (in one area, there is a spot that looks like a reverse dent like you see on original alloy bodies) so I called my Shelby dealer and he told me they had repainted nearly all of their fiberglass cars. I suppose I'll try and live with mine for a while longer, then paint it again.

Nuts.

[strictlypersonl]

Black, or any non-metalic dark color will show body waviness more than lighter colors. Many painters actually charge more for black because they have to be extremely picky when they do the body work. Fiberglass's instability just increases the long-term problem.

[Silversmith]

I am greatful that I own a ERA! After 20+years & 8,000+ vintage race & street miles the glass is still just like new! You would never know the original 12 coat rossa red paint job is also 20+yrs old. Nerry a crack! anywhere!! Thank God thoses guys in New Britain CT. really know there stuff when it comes to glass & building a totally awsome AC replica PS- This AC has always been garaged when not in use. It doesn't sit outside in the sun for days on end; as I'm sure most don't.

[Silversmith]

I am greatful that I own a ERA! After 20+years & 8,000+ vintage race & street miles the glass is still just like new! You would never know the original 12 coat rossa red paint job is also 20+yrs old. Nerry a crack! anywhere!! Thank God those guys in New Britten CT. really know there stuff when it comes to glass & building a totally awsome AC replica

[razerwire]

Good fiberglass work is hard to find. I was into drag boats when I was younger and good materials and people who knew what they were doing was more the norm back when. There was one boat builder that had a bladder inside mold to squeeze out the excess resin which made a lighter and stronger hull. Their is still some in the boat business who do good work. The best I have seen lately is -Smooth As Glass- in Riverbank ca. My fiberglass brake ducts were rubbed by tires and tore up. Changed shape to give more clearance, took to Smooth As Glass shop and he repaired and changed shape to my specs and did a great job. As for the rest of my Kirkland the aluminum is still straight, thank you very much.

[Obsessive]

Originally Posted by Silversmith

I am greatful that I own a ERA! After 20+years & 8,000+ vintage race & street miles the glass is still just like new! You would never know the original 12 coat rossa red paint job is also 20+yrs old. Nerry a crack! anywhere!! Thank God those guys in New Britten CT. really know there stuff when it comes to glass & building a totally awsome AC replica

I owned an ERA before I bought the CSX. The ERA glass was perfect and I have to agree with you.

[just dreamin]

I am not an expert but I have been told that polyester is the normal type of fibreglass that is generally used. This is not as stable as vynelseter that is supposedly much better but does cost more. Also some manufactures here are using kevlar in their bodies and promoting that as being the best option. I am somewhat surprised that a fibreglass expert hasnt given us the latest lowdown on the product.

[mdross1]

Our 20 yr old car has the same issues been that way for a while now.We drive our car and it gets the usual road damage we accept it.Years ago it used to bother me to a pont it made no sense.We do not live in operating room conditions.Besides rubber bebees on the rear quarters adds to the pateena.

[Snake2998]

My kit was bought in 1985 and the black gell coated body was left outside in the sun for 5 years whilst I acquired and assembled the mechanicals to let it "settle" and get rid of most of the wiggles and bubbles before painting, but even so it is still settling somewhat.

Like most of you I am a true petrol-head, but unlike some of you I believe that the Cobra was primarily a race car and was never intended to be a show car, so I have never bothered with authenticity, or quality of shine or finish and prefer my car to look like a much used toy that has it's fair share of battle scars and whose form follows function.

This means that it gets washed maybe once in a blue moon, and if I feel that something needs changing or adding I do that without worrying about authenticity. Despite my apparent "negligence" the car still creates a sensation whenever I go out in it, or park it somewhere, and still gives me a thrill every time I drive it.

So, I think that the wrinkles don't matter, and the OP is right to just live with them.

The only time I will "normalise" my car is if I see a financial advantage in it when I try to sell it one day.