gel coat repair

tjanna

tjanna

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Can anyone recommend a DIY idiots guide? preferably UK without the American drama! I have some stress cracks just above water line that a surveyor had picked up and reported on. The local GRP man turned his nose up, so looks like its up to me to fix.

Thanks Gareth
 
simple boat maintenance by Pat Manley - got a section on gelcoat repairs

i've read the section then done it :) - only for chips not for stress cracks.

the advice for stress cracks seems to be:
1. open up cracks a bit with a dremel or similar ensuring that you go right to the end of the crack so no crack remains
2. mask off the bits of boat that you don'w want to plaster with gelcoat repair
3. get a tube of appropriately coloured (white?) gelcoat (two part) repair paste - it is made by the plastic padding people IIRC
3. apply to cracks ensuring some overlap onto surrounding gelcoat and ensure that repairs stand proud
4. allow to dry and then use slightly coarse wet and dry (used wet) on a sanding block to rub down until flush - going progressively finer to about 1500 grade.
5. then use a cutting paste if necessary to get absolutely smooth

smile and pat yourself on the back - once done you'll never go back to having chipped gelcoat :)
 
Practice somewhere invisible - under the cockpit locker or anchor locker lid - before taking your Dremel to somewhere very visible! It's not hard, but your first couple of attempts may not be as good as you would like.....
 
If you buy proper gelcoat from a supplier such as CFS then you will also need to put a wax additive in it or it won't go off properly if you don't exclude all the air. You'll be left with a tacky surface and will need to remove it and start again. It is however very easy to exclude all the air using resin proof tape on small repairs such as stress cracks. If you don't fancy that then you can buy it with the additive already added - it's called flowcoat.
I also have a few gel cracks to repair next month and will be using resin proof tape over the gel. I hope it warms up a bit in the mean time as the small repairs I did the other day took hours to go off.

EDIT: You don't need a dremel for cracks either, you can use the sharp corner of a chisel to turn the crack into a good V shape by dragging it down the entire length of the crack. If you already have a dremel and are happy with using it then that's perfectly fine too.
 
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Thanks all for the sound advice. You've made it all sound a bit to easy.

Practice somewhere invisible :encouragement: pretty obvious really but I wouldn't have done it!!!

I shall report back and let you know how I get on.
 
G12 said:
If you buy proper gelcoat from a supplier such as CFS then you will also need to put a wax additive in it or it won't go off properly if you don't exclude all the air. You'll be left with a tacky surface and will need to remove it and start again. It is however very easy to exclude all the air using resin proof tape on small repairs such as stress cracks. If you don't fancy that then you can buy it with the additive already added - it's called flowcoat.
I also have a few gel cracks to repair next month and will be using resin proof tape over the gel. I hope it warms up a bit in the mean time as the small repairs I did the other day took hours to go off.

EDIT: You don't need a dremel for cracks either, you can use the sharp corner of a chisel to turn the crack into a good V shape by dragging it down the entire length of the crack. If you already have a dremel and are happy with using it then that's perfectly fine too.
Click to expand...

This is excellent advice. I did it with a DULL chisel worked fine for me. I bought the gelcoat from a shop that was allready, with the wax init. If no wax it will not set properly.
 
P.S. The Plastic Padding Gelcoat Filler kit is not proper gelcoat, but it's easy to work with and does a decent job - particularly on older boats where the existing gelcoat will have aged and it will be difficult to get a good colour match. If the boat is brand new, then I would go for the real thing, getting it from a specialist supplier to match the paste used by the manufacturer. On a weathered boat ten years old or more, I don't think I would bother - PP Gelcoat Filler is going to do a decent job and it will take an enormous amount of effort with gelcoat paste, styrene wax and assorted pigments to do noticeably better.
 
Well I managed to pin down the GRP man for a price to repair the 10" x 4" crazing and was quoted a whopin £150.00 :nightmare: and he was seriously expecting me to go with it.

So out came my dremel, I v'd out all the cracks, cleaned with acetone and filled with gel coat filler, 1/2hrs work. Following day wet and dry P240 (or something there about) with an orbital, 10 mins. Gave it another fill say 5 mins. So when dry it got another wet and dry, progressing to a finer polish, you get the drift. The whole job took just over an hour and have to say its near on bloody perfect, if I was gong to be picky the colour is slightly off. Even the grp man stated his repair won't be the same colour. Pat on the back for me and £135 better off. Happy Days :)
 
tjanna said:
Well I managed to pin down the GRP man for a price to repair the 10" x 4" crazing and was quoted a whopin £150.00 :nightmare: and he was seriously expecting me to go with it.

So out came my dremel, I v'd out all the cracks, cleaned with acetone and filled with gel coat filler, 1/2hrs work. Following day wet and dry P240 (or something there about) with an orbital, 10 mins. Gave it another fill say 5 mins. So when dry it got another wet and dry, progressing to a finer polish, you get the drift. The whole job took just over an hour and have to say its near on bloody perfect, if I was gong to be picky the colour is slightly off. Even the grp man stated his repair won't be the same colour. Pat on the back for me and £135 better off. Happy Days :)
Click to expand...

well done. do you have a photo just for forum gratification?
 
I remembered to take the camera and managed to get a couple of shots today. 1st piccie is straight on, which you can clearly see the difference in colour. 2nd from the side and you cant see the repair at all.
032.jpg033.jpg

Gareth
 
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