How should I repair this please?

[Pecheur Anglais]

When cleaning my RIB I noticed a chip in the base of the transom, right on the edge where it meets the underside of the hull.

I picked the loose bits out leaving the hole as shown in the photo. It is about 30mm wide and 7mm deep at the deepest point.

Not having experience of grp repairs, but seeing it as only small and superficial damage, I would like to fix it myself.

Would a gel coat repair kit be appropriate to do the job or do you have any better suggestions for me please?

[jwalker]

Originally Posted by Pecheur Anglais

....I would like to fix it myself.

Would a gel coat repair kit be appropriate to do the job?

Yes. Plus some pigment to colour match the hull.

[spartacus]

Gel-coat and build up in layers given the depth. Once you've reached the desired level, 3M wet and dry sandpaper and go through the fine grit levels grit on a sanding block with a little Fairy Liquid to lube. That's the laborious bit, but will bring back a decent finish. Just keep rinsing the area and getting rid of the gel-coat residue. If you have a rotary mop with a foam pad, you can use Menzerna 203 or similar to polish up.

[Maximus]

Originally Posted by spartacus

Gel-coat and build up in layers given the depth. Once you've reached the desired level, 3M wet and dry sandpaper and go through the fine grit levels grit on a sanding block with a little Fairy Liquid to lube. That's the laborious bit, but will bring back a decent finish. Just keep rinsing the area and getting rid of the gel-coat residue. If you have a rotary mop with a foam pad, you can use Menzerna 203 or similar to polish up.

X2

All good advice you'll find a rubber sanding block (it'll help get a flat repair to match original surface) and some washing up liquid in the water for the wet and dry will help too.
You can buy white gel coat repair filler off the shelf

[Pecheur Anglais]

Thanks jwalker, spartacus and Maximus.

That gives me the confidence to order some white gel coat and catalyst, then get stuck in. Fortunately I have all the other stuff mentioned already, apart from a rotary mop. Guessing that's not a problem as its only a small area to polish.

[beamishken]

Remember you need to add wax to the final coat of gel coat or it will stay sticky & be a bugger to sand. Gelcoat filler will be different & should go off alternatively if your using gelcoat you can cover with brown packing tape to make it go off.
Gelcoat is designed to stay sticky to adhere to subsequent layers of glass & resin, to get a full cure you need to either add wax or cover it to exclude the air to cure fully

[Orwell boy]

These people talk about making a dough for deeper gouges ,they will have all you need if you cant source locally https://www.ecfibreglasssupplies.co....gelcoat-filler
At the risk of maybe upsetting the purists i have had good results years ago on a sports boat with a tube of white plastic padding ! .

[Poly]

do you know how it happened? I've seen damage a bit like that on a badly set up trailer that let the boat move forward of the last transom roller. if its something like that - make sure you fix the problem too - or you'll be repeating it next week.

[gtflash]

Agree. 7mm is quite deep, just using catalysed gelcoat might not last. Gelcoat is extremely brittle and has no strength. I would use a gelcoat filler, which will also eliminate any need for wax on top layer etc.

Don’t think they make plastic padding gelcoat filler anymore but there is still stuff out there and ec sell their own, it is thick and gooey and easy to shape. But quite hard to sand so don’t go crazy

[Limecc]

G-flex 655 thickened epoxy mixed with a few chopped strand matting fibres (cut down in length) would be the way to go in my book. The fibres add strength and stop the epoxy from sagging. Afterward go over it with Flowcoat (gelcoat with wax) and finish off through the grades and polish.

West Systems also sell a 501 white pigment which can be added to the epoxy, I get West Systems products from Amazon.

[mal99]

How did the damage occur? If its a one-off and unlikely to get bashed again I'd try this first:

https://www.force4.co.uk/item/Plasti...oat-Filler/CP4

[Orwell boy]

Originally Posted by mal99

How did the damage occur? If its a one-off and unlikely to get bashed again I'd try this first:

https://www.force4.co.uk/item/Plasti...oat-Filler/CP4

I tend to agree with this way forward ,and for those who may need colour or even changing the shade of white ,i have seen it suggested to use a artist paint pallet of colours , however i cant recall whether it was watercolour or oil ?
much better option than £10 per pop trying designated gelcoat colours

[Wave Rider]

Speak to https://www.ecfibreglasssupplies.co....gelcoat-filler
They give good advice

[gtflash]

Originally Posted by Limecc

G-flex 655 thickened epoxy mixed with a few chopped strand matting fibres (cut down in length) would be the way to go in my book. The fibres add strength and stop the epoxy from sagging. Afterward go over it with Flowcoat (gelcoat with wax) and finish off through the grades and polish.

West Systems also sell a 501 white pigment which can be added to the epoxy, I get West Systems products from Amazon.

I have had good and bad results with gelcoat over epoxy. Boatworks today did a great review of gelcoat over west epoxy that worked. Despite that he still doesn’t do it.

Have you used 501 white pigment succefully in open air? I found west pigment changed colour quickly as all epoxy does when exposed to UV. I’d be curious to know if you have a better technique than me, as I have a smal repair which would benefit from epoxy strength but is exposed to outside and UV.

[gtflash]

Originally Posted by Orwell boy

I tend to agree with this way forward ,and for those who may need colour or even changing the shade of white ,i have seen it suggested to use a artist paint pallet of colours , however i cant recall whether it was watercolour or oil ?
much better option than £10 per pop trying designated gelcoat colours

That stuff works. It’s the plastic padding replacement I believe. An easy repair. It’s Highly unlikely a first timer will match pigment. It’s almost not worth bothering, a year later it all looks the same.

[jeffstevens763@g]

Colour match will be very difficult since it’s now weathered even if you have the correct RAL number I would make the repair such that it looks like it an insert and should be there IMO