Topsides and... automotive paint?

Cookie Jar

Cookie Jar

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Hi everyone,

Ok, I understand you're probably laughing right now :o , but before you start bashing me let me explain:

I have an open daysailer that will be "dry sailed" in inland (fresh water) next season.
The reason I'm "considering" this option is not because of costs, but rather because of color availability. I live in the Czech Republic and the available topside colors or even brands of paint seem to be extremely reduced.

Cookie Jar will be fully painted and the antifouling below the water line is not a problem... but topsides are (if you want anything beyond the classic red or blue)

Is this even possible (GRP hull)? or will it "come off" in a blink?


Thanking you in advance,
"Cookie Jar"
 
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In my experience of using good quality 2K finish on Grp top sides the results have always been successful if sprayed on. Like all things, preparation is the key to longevity in both surface preparation and conditions of working, temp, humidity etc. Some care has to be taken with breathing apparatus as the paint produces cyanide fumes. Two pot polyurethane has also been successful, again just beware of the vapour. Some repairs that were completed in excess of ten years ago are still just as good as the day they were done. These are vessels in seawater. No problems. Spray finish is relatively easy for a perfect finish as hand painting 2K is not advisable.
John Lilley
 
Wow... thanks a lot for the prompt replies guys!

johnlilley said:
In my experience of using good quality 2K finish on Grp (...). Spray finish is relatively easy for a perfect finish as hand painting 2K is not advisable.
John Lilley
Click to expand...

Thanks for the hint Johnlilley, but please excuse my ignorance on the subject... what exactly is the "2K" you're mentioning?
 
2K is the generic name given to the two component paint used for car refinishing. Similar to two pot polyurethane in that it requires a hardener mixed with the paint but it is a slightly different formulation. The applications are similar although probably more choice of colours in 2K finish. Look up 2K paint on Ebay for instance.
John
 
I trailer sail my trimaran and after stripping off the various layers of old anti-fouling when I bought her four years ago I sprayed the bottom with some two pack paint I had left over from painting motorcycle fairings. It's stood the test of time well, even along the centre underneath where it is dragged along the trailer bunk board sometimes.

The only problem for me is that I did it in blue, which upon reflection isn't the smartest colour to paint the bottom of a trimaran... :)
 
My previous boat (Anderson 26) was black and had a respray under the previous owner in car acrylic in 1998. I sold her in 2006 and apart from any impact damage she still looked lovely...
 
As far as I'm aware car paintwork at the coast suffers most from eagull droppings and rust from beneath, so should do as well on a boat's topsides. My own boat das a light vlue sdearline strake, which I suspect is painted - probably cellulose paint as it's from the late seventies. Of course, every year it gets a little lighter in hue and polishing has revealed a darker undercoat or primer. Very tempting to respray with a modern topcoat!

Rob.
 
In fresh water you should be fine with automotive type paints but best result will be with a clearcoat finish to protect the colour. In salt water they perform much less will in terms of colour and closs retention. Adhesion should not be a problem.
Automotive paints will be much less durable than marine paints in impact and abrasion resistance as the cured resin is more brittle and the coating generally thinner than a 2 pack polyurethane.
Be very cautious with the advice from John Lilley. Clearly coatings are not his strong point!
Solvents and fumes released by any 2 pack paint are not very nice so you should take care with PPE and follow instructions. However, car refinish paints are usually acrylic based and do not release any cyanide! 2 pack polyurethanes are often, but not always, isocyanate cured and free isocyanates will be released when sprayed. Not cyanide but still not good to breath so full airfed breathing equipment should be used and fumes should be scrubbed before release to atmosphere. He was, at least, right about the 2k bit though.....
 
Thanks for the hints Pasarell, especially the "health beware" ones...

I will investigate further on this before making any decisions on which one to choose... So far all I know is that it will not be a "marine grade" one.

Thanks again!

Ahoy,
"Cookie Jar"
 
FWIW you can add plastisers to 2k to make it more durable given the application so no worries regarding using automotive paint and as mentioned above a couple of hits with clearcoat and thats the UV problem sorted. I've sprayed everything over the years and have never quite understood the pricing of international' perfection or Hempels Diamond......whatever its called.

They're both common or garden 2K PU the likes of which can easily be purchased from anywhere for a fuk site less than a swindlery. The 'Marine grade' thing is bollox as far as i'm concerned all that means is it may have a higher percentage of solids in the paints chemical compostion again nothing out of the ordinary and easily purchased online or from an automotive concern along with thinners/extenders, plastisers, cold temp additives, etc etc.

Make sure you get a decent respirator, although if doing it with a brush and roller outside the fumes wont be nearly as bad as HVLP or airless.
 
I read somewhere that the best paint for topsides was BMW white on the grounds that you can get it anywhere in the world! Rattle cans for touch up are easy and cheap.
 
My last boat was an epoxy/Kevlar pre-preg construction, and gelcoat is not possible. They were all factory 2K auto paint (Imron) and did very well. Not low-end boats, either.

I would do it without a second thought, if Awlgrip were difficult to get.
 
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