Repairing Glassfibre - Addendum

The main article about repairing glassfibre is located here.


When repairing Glassfibre - remember "Safety First":

1. Always wear a mask when grinding, glassfibre dust is harmful to the lungs

2. Always wear goggles

3. Wear rubber gloves, particularly when mixing resin and catalyst, to protect against heat generated

Take care when handling hardening agent for resin, usually benzol peroxide, it is harmful t the skin and can cause blindness

Now Let's get started:

1. Crack in the paint, or crazing in the gel coat almost always indicate damage to the glassfibre beneath. Stress Cracks are caused by movement of the body.

2. To check the extent of stress cracks rub down the damaged area with 40 grit sandpaper until you've gone through the paint and gel coat to the glassfibre.

3. To see the cracks in the GRP wipe the area with spirit wipe, not thinners as this can damage the GRP. If cracks extend beneath the paintwork, keep sanding.

4. Grind down the cracks until they disappear completely. If a crack is bad, you'll need to grind right through to the glassfibre. Don't be afraid to do so.

5. Make a paper pattern and cut a piece of glassfibre matting to match the area you've sanded. Don't make it too large so you trap old paint beneath new matting.

6. Pour pre-accelerated resin into a plastic container, then measure the catalyst using polythene burette and mix them together. Gloves are a must.

7. Paint resin over area to be repaired, lay on the matt and thoroughly wet it by 'stippling' it with the end of the paintbrush, brushing may cause matt to come apart.

8. Firm stippling will also push out any air bubbles trapped in the matting.

9. Once it's dry, rub down area until it becomes flush with the paintwork.

10. Once matt is smooth, use a brush or an airline to clear away the dust.

11. Fill any small craters with extra resin, then top stopper or very fine filler.

12. Crash repair is easier than you might expect. Grind down the damaged area as before, grinding back beyond the tears. You will need to bridge any gaps to retain the right shape.

13. What do you do if there's a gap? What would you with steel? Make a new bit to fit. Screw strip of steel or tin on to the inside or use tape to hold the shape and support the new matting.

14. Using thin strips of matt, build up the shape inside the wheelarch. Once again use plenty of resin and stipple it in with the brush to get rid of any air trapped within the matting.

15. Cover the whole inner area with one larger piece of matt and soak both sides in more resin.

16. Once this has dried apply matt on the outside, taking care to duplicate original line, then sand down.