Painting Over Gelcoat?

D

dhj

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Hello Yuletide fonts of knowledge...

I have found an otherwise sound 1970's GRP boat for sale. It is quite cheap, presumably because of its hull colour: brown. That was the original gelcoat colour! The interior is out of an episode of The Good Life, but that'll be easy to fix...

Is GRP easy to paint? Shoud it be sprayed? Will it stick, or will it flake off over time?

Input gratefully received.
 
It is a well established process, painting over GRP. DIY or Professional. If you're doing it yourself then everyone agrees that preparation is 90% of the job. If you're getting somebody else to do it, then paying the bill is 100% of the job, but it isn't cheap.

Look up the International Paint web site (or any other manufacturer), plenty of advice available.

Jeff.
 
Don't do it !
....Unless you are thinking of another dark colour-are you?.
Any dings in your shiny new white topcoat will reveal brown.. Be like cosseting the paint job on a steel boat.
Your affordable early 70s brown Westerly(say) now becomes an expensive choice,whose resale value next time around could be affected too.....All imho
Have you considered just sailing with it as is?
 
>Your affordable early 70s brown Westerly(say) now becomes an expensive choice,whose resale value next time around could be affected too..... <

Blimey Blueboatman!! I would have thought any improvement on brown would hugely improve the value!! FWIW, a proper (2 or 3 coat) undercoat system before a similar number of 2-pot topcoats, will take a fair bit of punishment before showing signs of wear.

And any dings dep enough to reveal the brown gelcoat will be easily touched up.

No, I'd go for D H-J. Changing a ghastly brown (sorry!) to white will be one of the best things you could do!

Merry Christmas!!
 
G'day David,

If you are not a dab hand with a spay gun don't panic, as spraying is completed in under an hour so the cost to hire a good gun hand is minimal.

Preparation is the costly bit, you need to wash it, sand it, fill it, wash it, sand it and then perhaps do all of that again. When you think you have it about right you can apply your first coat of primer, this will show all the little bits you missed and any contamination left on the hull. Fix them, wash them, sand them and apply another coat of primer and check for pin holes and contamination. By now it should be looking pretty smooth, so you can apply the final primer coat. Don't sand this till you are ready to paint the top coat, this ensures the surface is clean and fresh.

Use a 2 pot polyurethane, look for one with long chain polymers like Internationals Interspray 900, very good self leveling qualities.

Notes:

Use epoxy resin and microballoons to fill imperfections.

A plastic ruler will bent to the hull shape when applying the epoxy and filler, this will reduce the sanding time and effort.

Wash before sanding to remove resudue left by the curing process, a simple running hose and a green plastic scotchbiight pad is you need, rub till the water no longer forms beads, this only takes a couple of minutes.

Stay well up-wind when the spraying is in progress, this stuff is not good for you.

Have you given any thought to epoxy coating below the water line?

Andavagoodchrissie......
 
You'll find that when you are sailing you can't see the topsides.
When you are rowing out to your boat you are looking back to shore.

So you've only got to get over the trip back to shore.

Seriously, any dark colour would be better as dings wouldn't show through. Black, green, blue. Why go for white?
 
Anybody remember the days of wooden boats when you got your brush out every spring to touch up any gouges. Then every five to seven years you painted the whole boat.
Then came fiberglass and suddenly it had to have a shine good enough to be able to shave in the reflection.
I don't know the size or manufacturer or price compared to others of this type of this boat but that would have a bearing on which paint I would use. It is too easy to spend a 1000 pounds for awlgrip with all the extras needed. Without doubt two part paints are the best available but I know many people who are sailing along happily with Brightside or Easypoxy and pocketing the 750 pound savings.
The problem with spraying, I assume outside is having someone on standbye for no wind no bugs etc. as well as pollution laws.
 
I'm with the 'keep it dark' fraternity. Seen too many boats with white paint over dark gel to want to own one. But something like blue over brown should be fine - any scratches unlikely to show - and it would enhance the value.
 
Go for it! I painted my 1979 Contessa 32 myself using Toplac one pack enamel. I had never painted a boat before, and I chose the small, rounded end, felt surfaced rollers much favoured by the Dutch. Three coats were applied over three days (in the winter I might add) and the result? A number of people thought the boat had been sprayed, and I eventually received top money when I sold the boat. The moral, of course, is to listen to conflicting advice, ignore the stuff from those who haven't done it themselves, choose the simplest method available, and get on with it!
 
Yep. Electric sander. 120 grit paper. One pack paint. slop it on.
Keep paint pot warm in a bowl of water, not so hot it runs and skins, but not so cool it doesn't flow.
The yellow has been on 2 years in this shot.

Antifoul01.jpg
 
It's not a Catamaran (Prout ?) is it? There's a lovely looking one down here........ dog sh#t brown hulls, topped with caramel decks. /forums/images/graemlins/laugh.gif I'd love to know what colour schemes they REJECTED, before saying to themselves "this is the best one" /forums/images/graemlins/grin.gif /forums/images/graemlins/grin.gif

If it's anything like that you would probably MAKE money when you sell it - or at least break even. /forums/images/graemlins/laugh.gif

As already said, go for a dark colour. As long as the prepartion is done properly the paint itself will stick (and stay stuck) to the GRP, just that the colour won't be part of hull in the same way. Any dings can be touched up. The colour itself may not last as long with a "straight out of the factory sheen" as the original - but more than OK for many many years - and a bit of polish every now and again worlks wonders.
 
LakeSailor

I presume you haven't been using photoshop?? /forums/images/graemlins/cool.gif

That looks a very nice job - it holding up (on!) ok?
 
Well it was 2 years old there and is now in Edinburgh. So let's hope so.
Actually, apart from where the eye on the mooring bouy kept bashing it, it was very hardwearing.
 
Having done the job myself ...

I would never consider using the undercoat again - it was so difficult to apply well, being thick and "gooey". When I went back to suppliers - the actual paint people - they agreed that the undercoat was a pain. They even agreed that a lightly sanded gelcoat to provide a key is good enough to take top-coat !!

If I was to do it again - I would not use the two pack undercoat ... but double up on the two pack top. Lightly sand the gel-coat to provide a key ... and away you go.

It is interesting that Blakes and International both used to say they were designed for brushing, pad, roller, airless spray BUT NOT air-spray ..... My experience agreed - where I brushed and it looked fine ....

One word of caution .... make sure all salt is removed from surface and try to shield your work untill dry - I have surveyed a few boats with strange tiny spots in the top-coat ... this is due to salt in the air getting onto the paint finish before fully dry ....
 
Re: Having done the job myself ...

Hmmmm. I've painted two boats > 30 feet LOA ( and several smaller ones) and had no problems using the two-pack undercoats. Mind you, the boats were painted indoors, so maybe that had something to do with it.

The first I did, some 21 years ago, using Perfection 708 (709?) using 2 u/c's and five topcoats (all wet and dryed between coats) still looks fantastic!! I had the boat for 4 years after it was done and my close friend who bought her from me, had her until two years ago. Most people assumed it was the original gelcoat. And that paint was covering a dark blue hull!!!!

Two of us applied the paint, a friend 'laying on' in front of me, both using incredibly expensive brushes!!

Despite the views above, I would still personally go for white as opposed to a dark colour that will always fade in time and is difficult to finish well enough to show a shine that will stand CLOSE inspection. Somehow this seems easier to achieve with white or other light colours. IMHO, a white painted boat would be more sellable than a dark colour, whatever the perceived downsides are.
 
Exactly as Oldsaltoz says and I also strongly recommend that unless you are accomplished with a spraygun the short time taken to spray a boat makes it almost senseless to do that oneself and run the risk of a botchup. As Aeolius IV says the preparation is 90% of the job so is where one can do it oneself and make savings if so wished. Get a pro to spray the build coats also so as you have less sanding and better and more consistant film thickness. Rolling, brushing, tipping off etc will never give you a professional like finish (if that is what you are after).

All the comments about the brown underneath being a problem if you paint white are false if you do as salty one has said, including using a good linear polyurathane top coat, as you will end up with an extremely durable and very hard finish. In any event in the case of any severe accident to the coatings it will be easy to repair (far more so than a gel coat repair). If white you should expect at least 15 years service from it and for the common darker colours of blue and red at least 10 years.

A comment was made about having problems like a steel boat if you use a light colour. I have a steel boat and it was painted correctly as salty one describes. After coming up to 10 years of life it has never had the coatings breached through to the steel and that includes after our MoBo berth neighbour drove heavily into our topsides and scraped the screw heads of his rub rail along the side of us. I have seen some very hard hits on big boats I manage, including with structural damage, but rarely the coating breached through to the substrate.

John
 
Having painted a few boats in my time, the only constructive things I can add are:-

Use 2 part if you are confident, it gives a better finish but only if you can work quickly and right first time; one part top coats applied carefully and with good prep would be fine.

Dont worry about colour, if it flakes or gets knocked off then you did it wrong - whatever the colour was.

Lastly, dont underestimate the cost. Polish the boat and see if you can live with it, if not you have started the preperation for painting.

Merry Xmassy goodness!
Soong
 
Thanks for all the above. I had navy blue in mind.

I used to have a wooden boat, and used Dulux Weathersheild, direct from the second best chandler of all, B&Q (the best being, of course, Poundland!!). Worked a treat, but it won't risk it for this project...

...if you can enthuse about boats at this time of year, it's untreatable...
 
I'm glad it's helped you , but I'm afraid I was hoping for the final result , this is one of the jobs for my boat but I am still wondering which method is best. 1 part / 2 part paints , undercoat then topcoat / prep well top coat only , spray / brush / roller , shall we start a new thread and ask for votes ? /forums/images/graemlins/smile.gif
 
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