Deck paint and gelcoat cracks

[colind3782]

Here’s one for the paint experts!

The deck of my 33’ Furia was painted over by a previous owner to cover the original 1988 gelcoat and he made a complete hash of it which I would like to put right.

Where the paint has come off, in places the gelcoat appears to be finely cracked in a “crazing” effect. The painter said that the cracking is caused by the fibreglass flexing more than the gelcoat. He has quoted me what I think is a “go away” price of €4200 with no guarantee of success.

I have mentioned the problem to a friend with a lot of experience in the automotive painting business and he seems to think that the cracking pattern is more likely to be shrinkage rather than flexing or damage and, possibly a reaction to the paint with the gelcoat. His thinking is that flexing usually occurs in straightish lines along the flex rather than the fine crazing pattern that we have. Sorry, I don’t have pictures to hand.

I can’t afford to spend over €4000 Euros on a paint job that won’t be guaranteed anyway so it looks like it’s going to be DIY. Do the gathered experts have any opinions on a suitable paint to cover the cracks and any preparation required?

Thanks for any help

 

[richardbrennan]

I cannot advise on the cause of the crazing, but assuming it's now stable, Kiwi decking is probably thick enough to cover the cracks.

 

[PCUK]

Grind off the old gelcoat and fill and fair with epoxy. Then repaint as required.

 

[yoda]

I had the blue deck paint removed from my yacht by grit blasting, It was a messy job (because the grit goes everywhere unless you are in a tent) however the results were fantastic with the original gelcoat exposed without damage to the non-slip pattern. While there 1 or 2 minor cracks the majority of the deck was as original. It could be that the area of cracking you have seen is the only problem area however if you do remove all the paint you can always re-paint, Kiwi Grip or even use non-slip flow coat to re do the deck. (Cost about £800 to have my 34ft boat blasted).

Yoda

 

[colind3782]

The non-slip areas don't seem to be showing any cracks, it's the smooth areas, especially on the cockpit comings and coachroof where the problems are.

 

[pandos]

I had what may be similar crazing on my gel coat, which I think was caused by the heat in the Med. I Sanded and applied two coats of primer (recommended by makers of inter-deck), sanded again and then applied a coat of inter-deck which covered it well, 4 years later it still looks ok but will be done again 2016.

Near the edges where I used ordinary paint the crazing came through. Someone has advised that I use an additive which is used in painting plastic bumpers.

 

[30boat]

My previous boat had the same problem. I sanded the old paint as much as I could and covered the decks with a very light roving and epoxy which was then painted with Inernational Interdeck. Never had a problem after that.

 

[Scoresby]

Cracks caused by flexing indicate damage to the substrate and possibly inadequate design. Flaking paint would indicate poor preparation/application/choice of materials.

Gel crazing tells its own story and often needs re-laminating.

 

[colind3782]

Thanks for all your advice. I think I'm going to treat a test area with epoxy and Interdeck to see how it lasts before making a move on the whole job.

 

[Minchsailor]

I saw this stuff in the Force4 catalogue:

www.force4.co.uk/magicezy-hairline-fix-gelcoat-repair-sealant-m.html?sqr=gel&#.Vm1Oly0X3mE

Never used it; no idea if it works, but may be worthwhile investigating.

 

[Yngmar]

I saw this stuff in the Force4 catalogue:

www.force4.co.uk/magicezy-hairline-fix-gelcoat-repair-sealant-m.html?sqr=gel&#.Vm1Oly0X3mE

Never used it; no idea if it works, but may be worthwhile investigating.

Meh. I've tried that on some gelcoat crazing on the bow (minor impact by PO). The price is really quite silly for the tiny tube you get. It's basically coloured superglue and while it made some improvement, the crazing is still visible. Not magic at all.

 

[johnlilley]

This sounds like u/v damage to the gel coat. Usually takes the form of a multitude of short random hairline cracks or crazing in the surface of the gel coat. Appears on surfaces square to the sun and is not usually structurally significant. Overpainting is not usually a guarantee of obscuring the crazing as it reappears in many cases as the paint is too thick to run into all the cracks and the surface deteriorates back to original appearance but then more difficult to fully conceal. The earlier post suggesting overlaying glass tissue and epoxy on the prepared gel coat is the most reliable method as the crazing cannot print through the tissue as it would through the paint. Finish with 2K finish paint.
John Lilley