Need to make some objects that will sit on/in water that need to be painted. I’d ideally make the things themselves out of polyester resin / GRP, maybe with a sealing coat of epoxy (I doubt the budget would stretch to epoxy throughout.

What would folk suggest as a finish coat? The colour scheme is just black and white, would be brush / roller applied and the paint needs to be well-behaved enough to be able to do detailing like text. The paint needs to be waterproof in its own right and if it saves having to coat the polyester with epoxy first thats a bonus.

I’ve used International Toplac for my boat’s hull, above the waterline to great effect. It will not be suitable for permanently submerged parts however.

How long is your item to be in the water? A two part system like international perfection may be more suitable it to be submerged for longer periods, but a bit more tricky to apply. If the item is to be permanently in the water, you may need some antifoul to reduce fouling.

How long is it in the water for?

Most yachts are polyester resin without epoxy and last 20+ years without osmosis damage. You could always compromise on vinyl ester resin.

How long is your item to be in the water?

indefinitely…. but probably not more than a few years

Below the waterline (which should be fairly static – the object will be in a pond (either tethered and floating or attached to a stake driven into the ground) and can be all black and won’t be seen. I only need a neat and detailed finish above the waterline

In which case, I’d recommend some antifoul for below the water line, fresh water / inland specific. It usually comes in 750ml tins but you will be able to buy 250ml “boot top” paint – same stuff, just generally harder to allow scrubbing.

For above the waterline I’d recommend Toplac as per previous. Hempel also do a range of well thought of paints, but I’ve neither used them myself nor were the current range available when I worked in a yacht Chandlers so hesitant to recommend…

Awlgrip paint for above the waterline

http://www.awlgrip.com/awlgrip-home.aspx

Thanks chaps

Plenty to go on there

Are you making the grp using a mould? Unless there are only two or three objects, it would be the easiest way to get a good finish on the top. If so, you can paint the required pattern in the gelcoat. Paint the black bits in gelcoat with black pigment, allow it to go off then paint white pigmented gelcoat over them, allow that to go off, then laminate the structure. When you take it out of the mould your pattern will be indelibly built in to the surface. This is the standard way to put a pattern in things like kayaks.

Either mould the bottom half all black and join the pieces (what I’d do), or if you want to be slightly quicker, fill the top with foam, laminate over it, and finish with a coat of black resin.

Are you making the grp using a mould? Unless there are only two or three objects, it would be the easiest way to get a good finish on the top

theres 4 to be made… to make just too few to make it worth making a mould really. The client might want an additional 2 – 6 in total might be worth it.

Quick q (sorry op), we have a beach hut. Always gets a bit mouldy inside during the winter even with gloss paint.

Will any boating type products help with that?

wwaswas you need ventialtion. Our beach hut gets a bit of mildew on the worktop over the winter, I could add more ventilation but it would be tricky as it’s actually built of block and render.

maccruiskeen: you’re def going to need antifouling below the waterline unless you/your client wants a lot of weed within a few months. Make sure you get the right sort of antifouling paint, if you get a standard ablative (eroding) paint you may find that the paint will lose effectiveness as it relies on friction with passing water to continually expose new layers of paint to keep weed at bay. As a pond will not have any water movement the paint will not be eroded and the paint layer in contact with the water will ‘die’ and stop keeping the weed away.
Check with a paint manufacturer which will be best for you – a copper based antifouling may be better than an ablative one.

Sharkbait – thats really handy info – cheers

The posters above have nailed it. Anti-foul of some kind for submerged bits, note that that will be a different colour and not gloss (hence two tone nature of boats often with a third co,oir as a line between the two). Also anti-foul doesn’t last more than a few years so really op you should lift out the object each year (more often) and give it a good clean and replace anti-foul as required. A dark colour below the waterline helps a bit.

My boat needs fresh Antifoul once per year,but it will vary from location to location. Ask around in the location where these things will be floating and youll find out which Antifoul is most effective for that location.