Best way to do a GRP repair

mjkinch1

mjkinch1

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I have a little hole appear in the GRP in the corner of the heads area. The GRP is a nice sort of creamy colour, but the pic below shows a magnified view of it. Its in a corner so not easy to get to, but I would like to repair it.

grp.jpg


Assuming this is in the realms of a reasonable handyman, is there somewhere I can get a FAQ or info on how to do a GRP repair and get the colourmatch? Can someone here give me some pointers?

Many thanks

Martyn
 
I think its more like a bad gelcoat installation, as there are no other breaks anywhere on the inside of the boat. It reminds me of an airbubble that has been covered over, so its rather thin, and at some stage someone has poked it and broken the cover.

Its a good point, but I cant see any other cracks or stress cracks on the boat, and the survey was fine (apart from this)

Also the paint has peeled a tiny bit on the frame around the window, exposing metal. I would also like to be able to repaint that if any ideas

Thanks

Martyn
 
I have uploaded this GRP repair manual (pdf) to my site which might give some ideas.

It would be best to right click the above link and save target as for speed.

As to flexing, the fact it is right next to a bulkhead is the give away, when was the survey carried out?

http://www.yachtsurvey.com/ has some scary reports about cracks like this appearing, may be worth a good read before you start donning the overalls. Not suggesting your boat has latent problems, just belt and braces really.
 
Is this part of the boat or just a liner for the heads area.

I am assuming this is just an insert added after the hull was built. It looks like when they laid the glass over the corner they could not get it to follow the gelcoat and left a void. The crack lower right looks like it is either very thick gelcoat or it has no support either. It would need to be looked at.

Have you tried to get the pigment from the manufacturer?
 
Polyurethane sealant (sikaflex or similar) carefully smoothed into the voids would keep the water out and take your eye off it a little. Not the correct fix but a quick and easy one.
 
IMH (and generally fairly ignorant) O, you'll have problems matching the colour. You can buy tints for gelcoat filler in various flavours, but it's si££y money and you may need a couple of colours and a dozen tries to get close. Unfortunately, paint is unlikely to last in a shower.

As mentioned above, it does rather look as though it's a place where the layup left a void behind the gelcoat. If so, it's of no structural significance and, colour apart, gelcoat filler will make a good repair.

Break out any more loose stuff. Any soap residue, grease, etc. will prevent the gelcoat filler sticking properly, so use a small grinding wheel to clean up the hole. The crud is irritant, so wear gloves and a dust mask. Vacuum out the debris & dust and fill with gelcoat filler, following the instructions on the tube.

From my days of gluing old bangers together, if the hole's deep, I'd be tempted to use a bit of the Isopon with glass fibres in it (P40?) to fill to just below the finished level then use a bit of gelcoat filler to finish off. You could use epoxy and a bit of mat if you've got it handy, but a little tin of Isopon or the Halford equivalent will work out a hellava lot cheaper if you have to buy it.

If the repair lasts, you haven't got a structural problem. If it doesn't, it's for one of 3 reasons, in order of probability:

1. The hole wasn't cleaned out well enough - solution: try again
2. The shower tray isn't rigid enough and needs reinforcing - solution: remove the tray and reinforce it with resin & glass cloth
3. (A long way 3rd!) The boat isn't rigid enough and needs reinforcing. - solution: get rid of it and buy one without a shower /forums/images/graemlins/wink.gif
 
G'day Martyn,

Please confirm if this is an internal molding, it sure looks like one; as SolarNeil has pointed out this could be just a bad lay-up. is this on the sole or the side?

The good news:
It can be fixed.

The bad news:
It will be visible, if not as soon as the repair has finished, then soon after; the new gel-coat will fade at a different rate than the original material.

This can be avoided by changing the colour of the effected area or better still in this case building something into the corner to cover it altogether. The change in angle will not show the difference in the shade mismatch.

Hope this helps

Avagoodweekend......
 
OK Thanks for all the advice - It looks just on the surface, part of the liner for the heads area - but I will take on board the advice regarding stress cracks and make sure it is superficial. The survey was done 6 months ago - full survey, and this was there then, but I have left the survey on the boat (don't ask - I have no idea) so will re-read it next week when I am over.

The actual szie of this is about a 20p piece.
 
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