Sunday 15 December 2019

Stern & Bow Compartments | Bilge Paint Dramas

I bought the PocketShip paint package and was a bit bemused to find it contained a quantity of bilge and locker paint.

The build manual says to use oil based household paint inside the boat, above and below the waterline.

I asked the vendor about this, and they said that bilge paint should be used in sealed spaces and below the waterline. In PocketShip this means the bow and stern compartments and underneath the floorboards.

Fair enough, I thought. Bilge paint is protection against water, chemicals, fuel and alcohol. Some if not all of those substances will doubtless find their way into this boat!

The bilge paint in the package was grey, but I decided that white would be better in the stern compartment where a deck hatch on either side of the cockpit would provide access for storage and sight of the inside of the locker.

I also thought that if it was attractive enough I could use bilge paint for the whole of the cabin interior.

So I purchased some white paint from the supplier and applied two coats with a 4" foam roller in the stern and bow.

It did not turn out well.

First, it has a very high gloss finish. I expected it to be matt or semi-matt, so that rules it out for use in the cabin where I want a satin finish.

Second, it settles to a very thin coating which does not fill any surface blemishes. It just forms an extremely thin skin, and the high gloss finish highlights any surface imperfections. So what I thought was a good enough surface finish for paint, wasn't. I had sanded by hand to a P150 finish but it really wasn't good enough.

Third, the paint did not dry smooth and flat. It resembled orange peel, apparently caused by microscopic air bubbles introduced into the paint during application and not dissipating as they should do.

This is not a very good pic, but you can see the high gloss and the orange peel.

I asked the paint manufacturer what I had done wrong. They tested the batch in question and as expected there was nothing wrong with it. They suggested it was probably caused by me not degreasing the surface with a solvent before painting.

So I sanded the stern compartment back to a bare surface. I left the bow as it was, given that it would soon be sealed forever and no one would see it again.

Then I sanded the stern compartment to a smooth and evenly matt surface, going through P80, P120, P180 and lastly P220 grits. The finish was so good that it put the rest of the hull to shame, so I resanded the whole interior to the same high standard.

I then degreased the stern compartment with white spirit and left it to dry, and then applied four coats of white bilge paint over consecutive days. The bow received the same number of coats. I again used a roller but swapped from a foam to a felt sleeve on the recommendation of my preferred professional decorator's merchant.

This is what the stern looks like now.

You are not supposed to use a primer for this paint on epoxy or fibreglass, which means that several coats are needed to cover the surface fully.

The finish is now very good - certainly good enough for the interior of a locker!

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