Fibreglass restoration

I am trying to build some knowledge in the following aspects of fibreglass restoration and would appreciate advice prior to getting stuck into the job.

My S130 is a 5 yard car, looks great from 5 yards … but upon closer inspection there are a number of gel cracks:

  1. Bootlid has loads, as if somebody has pushed it in the middle of the panel to shut
  2. Doorhandles have flexed the adjacent area
  3. Light pods have affected the adjacent panel.
  4. Roof panel has several cracks.

It sounds a good deal worse than it is, but they are nonetheless problems to be rectified.

I am expecting there to be many layers of paint, which should be removed as part of my schedule, which I am prepared for.
However, Miles Wilkins book shows only repairs to existing painted fibreglass panels with filler skimmed to match paint layers.
If you no longer have a paint layer, I guess you just lay up to the level of the gel coat prior with glass / resin prior to an overall coat of the tub with spray filler of some kind?
Having seen a few articles from Classics magazine (which showed the restoration of a rough +2) I note that the body was soda blasted which left a bit of a mess because of the state of the donor vehicle. I only managed to get some of the magazines in Australia.
A company called Option 1 (I think) decided to completely overlay the body with a new layer of mat / gel coat to resolve all of the problems - Miles Wilkins book does not cover this method at all.
What sort of substrate is required for this method?
Does the body have to have exposed mat all over, or is the mat laid over the original gel coat?
I have noted on many forums (US) that restorers of metal cars do not like soda blasting because contaminants from the process if not washed off thoroughly can affect the new paint. It also concerns me that a blasted exposed f/g shell needs to be washed with water for this purpose - (is this not the kiss of death?
If anybody has gone down this route and has a car that has been painted for a reasonable amount of time with no ill effects (or otherwise) I would appreciate your advice.

Justin

A lot of questions! I have used Miles? book as my bible for many years, and following his techniques, you can?t go far wrong.

Firstly, the way to fix gel coat cracks as you know is to grind off the gel coat layer all around the crack, and re-tissue in the ground out area. When rubbed down, this will be the same height as the original gel area. If you are doing a repair on a painted panel, then you will need to build up the level of the repaired area with a filler / primer to bring it up to the old paint level.

Option 1 do indeed tissue the whole car, and for very good reason. Our cars are now 35 to 45 years old, and contain not only the gel coat cracks that you notice ?splitting? your paint, but also smaller cracks that the paint is holding together. Combine this with years of amateur repairs to varying standards, and the strange composition of the very old fibreglass, and the only way they can guarantee their results is by re-tissuing the whole car. When Miles wrote his book, the cars he was fixing weren?t that old, and just maybe the finish didn?t last too long either.

Using water with fibreglass to wash off bicarbonate of soda isn?t a problem, so long as the shell is dried out thoroughly before any gel repairs or prep / paint is undertaken. Most fibreglass paint shops will put a shell in the oven / under lamps for 2 or 3 days after using any water, and this will get rid of all contamination. Certainly if the soda isn?t cleaned off properly, it will react with paint. It?s only a very mild alkaline, so there would have to be a fair bit of it. But I can imagine with a cheap re-paint job, the shell has been blasted, wiped over without too much care and painted.

There are two main reasons to use soda blasting. Firstly, it?s very economical. A shell, engine bay, doors, bonnet, boot and headlamp pods can be done in about 5 hours, and that includes every nook and cranny. You can only do 80% of the work with an orbital sander, then you have to do the corners and fiddly bits by hand?or most likely, not bother. This usually takes 100 hours at least.

Secondly, the soda blasting is a very gentle process, and you can remove a layer of paint at a time if you want. One slip with a sander, or chisel, and you have another area to repair / build up to give the correct profile. Soda blasting will also remove paint from the engine bay or under-bonnet areas with two advantages. It?s a de-greaser, so gets rid of all the oil contamination. It will also leave the original matting appearance of the under-bonnet / engine bay in a 2 seater, so if you like originality, it?s the only technique that does this.

The Plus 2 that was restored in the magazine had several attempts to remove the paint the conventional, mechanical way. After many hours, and realising was a mess the shell was in, they gave up with the conventional methods as they were making it much worse, and they had it soda blasted.

Mark

I wouldn’t assess repair method until the paint is removed-and even then I wouldn’t consider removing the Gelcoat lightly.It takes an expert to form the contours in resin properly.
The first Elan I stripped was 25 years ago.The one I’m doing now has had a respray and there are six paint layers-topcoat/primer/primer/original topcoat/primer/primer.I’ve counted 5 layers of paint in the original topcoat-so much for Lotus being skimpy.
All is being sanded by hand-and I’m about half way there.
Two things I’ve noticed in preparing my new car compared to the previous.
1-the original paint has the consistency of glass and very difficult to sand.
2-lots more gelcracks and microfractures!
My aim is to sand all the car down to the original primer.When thats done remove the last layer identifying/marking the body defects.
The Elan,in my opinion,has a bodyshell thats a little bit too thin in certain areas-you’ve noted boot,roof,pod mounts.I’d add wheelarches to that as well,possibly front apron.These areas all need reinforcing.
A +2 is a much bigger job-the larger panels harder to sand as they flex as pressure is applied.If going the Sodablast route I’d want someone experienced in removing paint from fibrglass and get them to remove the paint down to original primer.
I think its important to get intimate with your bodyshell :laughing:
when the paint is removed lots of those cracks/defects are hard to spot-they are much more obvious when finishing the bodyshell by hand than trying to spot them on a clean shell newly returned to you

I chemically stripped down to gel coat (marine supply), repaired stress cracks and breaks with fiberglass cloth/tissue depending on depth, brought surface back up the last bit with rolled on, gel coat (don’t have to get wax over it to get it to harden, available at marine supplies) then have used catalyzed urethane spray hibuild filler before color coats. Tons of sanding–usually wet to avoid dust, clogging–plenty of dry time. Gordon Sauer

I saw that +2 at Option 1 last year when my Sprint was in for repair- it was a serious MESS! They said it was the worst they had ever seen.
My car was repaired and painted after a t-bone incident which shunted me int a lamp post on the other side. Quality of repair and paint is excellent. Option 1 do not use any filler at all, everything is glass, tissue and resin.

Cheers,
Pete.

Justin et al, my few points to add to the replies you already have.

1/ You need to remove the paint down to the original primer/gel coat to really assess the state of the fibre-glass. There is a high probability of additional cracks or previous bodged repairs emerging.
2/ Previous repairs may have used excessive filler: as per Option 1 this should all be removed and proper surface built-up using glass, resin and tissue as required.
3/ For really high quality repairs (eg structural repairs where the nose cone mouldings join, most plus 2s disintegrate here) consider using epoxy with powder bound mat on the inside surfaces of the body). The epoxy bonding strength is typically 20 times stronger than that for polyester resins
4/ To remove air and ensure surface repairs into corners/hollows are fully compacted, vacuum bagging is an additional technique which can be used. I have a simple Piab ejector pump for this purpose.
5/ Miles Wilkens does actually state that for extreme cases with lots of individual gel cracks, the best approach is the remove the gel coat from the entire panel and provide a new skin via tissue and polyester resin. I mucked around on the front nose cone top surface with a DA sander until I eventually followed this Miles’ recommendation: an angle grinder with a 180 grit disk, guard removed and used flat is the best approach.
6/ The boot cracks are possibly a result of heavy handed closing but in reality the outer skin is too thin and poorly supported. Other forum contributors have suggested strengthening the boot skin by injecting foam between inner and outer skins. Downside is weight goes up considerably and may/will overcome spring tension. Suggest you check with others for feedback on this approach.
7/ Front and back of the body behind the bumpers are particularly vulnerably to damage. The boot floor supports also put excessive loads onto the fibreglass and you should inspect around here and beef up as appropriate.

Regards
Gerry

Additionally, my key lock cylinder on my +2S/130 was backed by a thin metal plate but not the door handles or trunk hinges (the inner one in the body, not the ones in the lid itself because they are exposed) and I backed all these with a similar metal plate to spread the loads. The plate is cut out to the size of the opening and then extends about a half inch. Actually this also made for a neater reglassing around the handle as most of the actual glass was broken off and missing particularly where it was narrow where the studs go through the door that secure the handle. I didn’t do anything to bolster the thin trunk surface and unfortunalely I believe that as low as the car is, it invites people to sit on it–came out from a bar in the '70’s to find a very large girl oohing my car from her perch on the trunk of my S3 DHC–yea, wasn’t long before I had all kinds of webbing. Gordon Sauer