reb53 wrote:Mine is 20 years old and I have yet to have a new crack appear.
I did it myself and did what the Wilkins book said, so I guess you can't get a much better recommendation.
Ralph.
That's impressive for any paint job
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Les,
I just thought I'd add a bit about repairing the actual 'glass. This method is basically Miles Wilkins with a few thoughts of my own.
The best results are achieved by stripping the shell back to bare glass. Various methods of blasting fiberglass have been discussed on the forum but I cannot comment. I did my shell the old fashioned mechanical way by hand and machine as in the Wilkins book. Others may well comment on experiences with blasting.
Note: I recommend that
before you strip your shell you either make photographs or detailed drawing of the size and extent of any problems because they are a bugger to see after the shell is stripped!
1. All areas of major damage should be ground back deeply into the fiberglass and feathered out beyond the extent of the problem. New standard weight matting should be laid in to restore the strength and approximate level. If you can repair from both sides do so although it's not always possible.
Repairs on the outer surface only can be just as strong but you need to ensure you grind deeply into the laminate.
2. Fine gel cracks and small cracks can be ground back until the glass matting is exposed (through the gel coat) and then repaired with a couple of layers of fine surfacing tissue (fine fiberglass matting). Make sure you grind the gel away well beyond the area of damage.
Note: On my own shell I took the precaution of adding extra matting to the inside of the shell (when I had access) to high stress areas where cracks typically appear. On a +2 the area near the pod pivot points is a good example. I added some under my wheel arches to try to lessen the effect of stone impacts.
Final shaping can be done with a good quality polyester body filler. There are no magic products, FWIW I have used U-Pol products for many years and find them reliable.
The last stage recommended by Wilkins (and used by me) is to spray the whole repaired and well sanded shell with a polyester spray filler. I used and am happy with U-Pol "Reface" Ideally you need a gravity fed spray gun with a large nozzle to spray it successfully and I foud in good conditions you need to move quickly because it will cure in the gun!
I have cut and paste the painting section from the old thread so it's all in one place .........
FWIW I can tell you the method I used:-
1.Repair the shell ready for paint and key the surface DRY with
production paper (p180 grade)
2.Apply spray filler as per instructions and again flat DRY with
production paper (p180)
3.Apply first 2K primer coats and again I flatted dry (p180) but at
this stage you could use water and p240 "wet or dry" paper
You could skip this stage but it gives you more chance of getting
everything flat and smooth
4.Final 2K primer coats flatted wet with P600-800
5.Colour coats flatted wet with p1500 and soapy water and then final
polish with an electric mop to restore the shine
Allow as much drying time as you can.
I have never known 2K primer to react with or indeed flake off filler
and therefore presumably spray filler
Poor adhesion is usually caused by inadequately keying the substrate
but 2K products generally have good adhesion properties.
On the spray filler and primer coats a "guide coat" (light dusted coat
of colour) greatly assists in seeing the highs and lows when you are
flatting
The method I used was based on Miles Wilkins repair and painting
techniques and my own instinct and experience
I am no authority on painting fiberglass (I paint tin cars) so it was
very much a voyage of discovery but I was very pleased with the result
and one (now 6) year on it still looks good.
I will just add my two mantras again
Keep everything as
dry as possible (including your air supply to the spray gun) in this I depart from Miles Wilkins.
Never flat glass or filler wet
and .......allow as much drying time as you can for every stage of the process, I don't mean hours, I mean days. If you are in a hurry, don't do it.