Repair nasty scratch to top side...

Captain Crisp

Captain Crisp

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Hi.
I had an unpleasant altercation with a rusty quayside last weekend...
I think these scratches need some proper filler etc...
Any advice?
Thanks,
Crisp
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Get a professional GRP repair guy. If you DIY it will show and you will waste hours trying to make it good.
A skilled repair guy could do it in a marina berth or wait for lift out. You could cover with sticky backed sailcloth or fablon if you are worried about water penetration. It will eventually be ground out over a large area and colour matched to disappear.
 
Not difficult if you can get a good gelcoat match. Filling and getting fair is the easy part, but on an older boat you will likely have to mix your own gel coat to match the existing. This is where the expertise of a professional pays off.
 
I would attack the scratches with wet and dry sand paper first. This might hopefully remove the minor scratches. Less than perfect might be something you have to live with.
Looking at the picture it seems a little to me like it might be a paint layer that has been breached. Not gel coat. If it is gel coat then you will see the fibres underneath. If it is paint then you need to sand down and repaint.
As said it is very difficult to cover a repair. Indeed you may end up repairing then eventually repainting the whole hull. ol'will
 
It would be very helpful if you mentioned the type of boat and age. Older boats had brushed gel coat which could be 1.5mm to 3mm thick, but most late 90's boats had sprayed gel coat that is 0.5mm to 0.75mm thick. Older hulls are much easier to get fixed by an owner. If more modern then I would get it repaired professionally - possibly as an insurance claim.

Whatever happens all the dirt in the scratches will have to be ground away, or black lines will outline every scratch.
 
As a short term measure (been there, done that, got the T shirt) get some International Gel Coat filler in white, mix a little up and scrape it across the affected area with a piece of flexible plastic (old credit cards are good for this). When it has set, any filler left on the surface will pick, chip or flip off while the stuff in the scratches will stay. Rub down with very fine wet and dry (2000-ish) and you're done. Unless the colour mismatch is extreme, nobody will notice the repair from more than a couple of feet away. You will, because you know it's there.

If you like having a really perfect, shiny boat you might want to get it professionally done, but if you aren't too twitchy it can wait for ages. I had several done this way which stayed unimprovd for years until I needed a bigger repair done, at which point the chap doing it used the stuff he had carefully matched to my gelcoat to fill every little scratch (including the ones I had patched) in the hull. It took him very little extra time as the hard work (matching) had been done.
 
Sorry to see the damage, fortunately IMHO looking at it it is not beyond DIY, it doesn't appear to have damaged the GRP only the Gel Coat, have a look at my images in the thread about two weeks ago 'Gelcoat Colour Matching'. The most difficult bit is matching the colour especially if the boat is older, (pigments fade and the exact pigment might no longer be available) colour can however be matched by mixing pigments.
Time is the real problem if a satisfactory repair is to be made, smooth back the proud BT's of the scratch with wet and dry, then cleaning out the damage (liberal cleaning with acetone to ensure no polish or other contaminent is there to prevent good adhesion) Use Topcoat ( Gelcoat with added wax to allow setting in air), apply it with small flat artists brushes and build up rather than try to fill the deeper scratches in one go, build up to a higher lever than the original, when set (at least 24 hrs) rub back down with wet and dry, I used 400 grit to bring to almost level then changed to 800 grit to get clser to level, 1500 grit to level and smooth surface, finally 2500 to give surface the shine to match the original.
I think anyone who owns a GRP boat should have in their library at home the book 'Glass Fibre Boats' by Hugo du Plessey, it's so full of useful advice on GRP.
 
If I remember from earlier posts about this Twister that it's hull has been painted, as William_H thinks.

In which case, you need not woory about matching the gelcoat colour because the fresh paint will hide it.

Matching the paint cpolour will be another story but at least if you don't get it right it's easy to scrape off and have another go!

I think car paint suppliers have a colour matching service and my local DIY shop does if you don't object to using non-marine paint.
 
Poignard said:
If I remember from earlier posts about this Twister that it's hull has been painted, as William_H thinks.

In which case, you need not woory about matching the gelcoat colour because the fresh paint will hide it.

Matching the paint cpolour will be another story but at least if you don't get it right it's easy to scrape off and have another go!

I think car paint suppliers have a colour matching service and my local DIY shop does if you don't object to using non-marine paint.
Click to expand...

Looking at the photo on a larger screen suggests you may be correct and the hull has been painted, the edges of the scratch look more like scraped paint than Gelcoat damage.
 
JumbleDuck said:
As a short term measure (been there, done that, got the T shirt) get some International Gel Coat filler in white, mix a little up and scrape it across the affected area with a piece of flexible plastic (old credit cards are good for this). When it has set, any filler left on the surface will pick, chip or flip off while the stuff in the scratches will stay. Rub down with very fine wet and dry (2000-ish) and you're done. Unless the colour mismatch is extreme, nobody will notice the repair from more than a couple of feet away. You will, because you know it's there.

If you like having a really perfect, shiny boat you might want to get it professionally done, but if you aren't too twitchy it can wait for ages. I had several done this way which stayed unimprovd for years until I needed a bigger repair done, at which point the chap doing it used the stuff he had carefully matched to my gelcoat to fill every little scratch (including the ones I had patched) in the hull. It took him very little extra time as the hard work (matching) had been done.
Click to expand...

I've just done my hull 'dings' ....

Bought a tin of two part Gel (White) ... looked over the boat to find any other areas and then put a small piece of blue painters tape next to the damage. Boat ended up with bits of blue all over areas on hull and cabin !

First ... took knife / thin needle file / sandpaper .... and made sure each was clean and KEYED for new gel to lock into.
I only mixed enough to fill a few nicks / scratches at a time as the Gel only has less than 10minutes working time ...

I used Ice Cream sticks to basically 'ladle' the gel in and then run across to remove most of excess .. but not try to make level - proud is fine.
Some videos / online guides advise putting tape over the wet gel to flatten - but I didn't.
Once all done ... leave it for reasonable time to really cure and then use sandpaper in varying grades till its smooth and level with surrounding ... finish of with T-Cut and polish.

Yes you can see the fills when sun shines on it ... but step back and look ? I find it hard to find mine and I never colour matched at all ... just used white gel on a white 1975 boat.
 
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