Monday, 29 July 2013

Painting a GRP Boat (2)

So, I removed all the fixtures and fittings from the cockpit, sanded every bit of GRP I intended to paint with
finer and finer sandpaper down to a paper grade of 125, filled every hole and scrape with filler paste, and washed the entire area with acetone, - and then I reckoned I was ready to paint. I chose International Paints Pre-Kote and one pot enamel ‘Toplac’ as a paint system mainly because it was easily available, but also because there was plenty of literature about these products on the internet and it seemed like the easiest paint system for an amateur to apply out of doors without specialist equipment. Before I started, I painted the bilges with Red Danboline and taped off the areas to be painted with masking tape.

I think I may have read too much about painting GRP and as a result I was nervous about tackling the job. On Monday however, I was out of excuses. The weather was dry and the forecast suggested there would be no rain in the near future. I had all the kit I needed and the wind was light.

In applying the first coat of Pre-Kote I followed the best advice I had been given –

1.      work with a small fine sponge- type roller;
2.      apply the paint union flag style – rolling in every direction rather than simply applying it in a right to left or up and down direction;
3.      put the paint on in thin coats;
4.      keep a dry brush handy to even out the coat and eradicate ridges or orange peel effects caused by the brush.

The coat went on beautifully and was touch dry within an hour or so, and just to illustrate how awful the boat had looked before, here's a close up of an area of the GRP surface before cleaning and painting.
Returning to the boat on Tuesday morning I was well pleased with the results. There were a few areas of ‘orange peel’ effects, mainly on curved areas and these were soon sanded smooth, using 240 grade sandpaper. So all was set for a second application of Pre-Kote, unfortunately (or maybe fortunately) before I could start, three guys turned up and began work on a boat next but one to mine. Looking at the equipment they brought with them I guessed they may be about to kick up some dust so I waited to see what happened. To my amazement, they set to work with a chainsaw and angle grinder and set about reducing their boat to neat one metre squares, which they promptly loaded onto a trailer to take to the rubbish dump.

Curiosity got the best of me. Here is the story. One of these guys bought this 22ft sailing cruiser on the water last year and brought her to the boatyard to over-winter her. She was a pretty fast light sailing cruiser of GRP sandwich construction. In essence, two sheets of GRP with a central core of foam. The boat had a large spade keel and she was laid up ashore with legs made of scaffolding poles to keep her upright. The legs served their purpose in keeping her upright, but they did not support the hull so all the weight of the boat rested on the keel which stood on hard ground. During the course of the winter the keel pierced the hull and came up through the cabin. Repair would have been too expensive and so the owner decided to cut his loss by scrapping her and avoiding any more yard rental fees. Within half a day she was gone.

Well, those guys certainly did kick up a good deal of dust so I had to use the early afternoon to clean my paint job before the second coat of Pre-Kote could be applied. It was four o’clock in the afternoon before I was ready and the weather was very very hot. I checked the thermometer and the technical specifications for the paint. The air temperature was about 35 degrees C, - top end of the paint’s range. According to the manufacturers, at this temperature, the coat would be touch-dry within an hour of application.

Like an idiot I took this to be a good sign. The paint would be well dry before the dew. Unfortunately, I hadn’t considered the effect of day–long strong sunshine on the GRP surface. I subsequently discovered that although the air had been 35 Degrees C, the GRP had been closer to 50 degrees. As a result, the paint dried as it touched the surface. Orange peel effects and hard edges couldn’t be smoothed out and, at times, the job felt less like painting and more like plastering. I should have stopped but I persevered. It didn’t look good when I finish and it looked even worse the following day.

Nothing for it but to sand it smooth. It wasn’t difficult but it was disheartening. Once again John Lee Hooker and BB King assisted me in retaining my sanity..

So, as of today, the boat has a cockpit with two coast of Pre-Kote on her and she is ready for her two coats of Toplack – but the heat wave has broken and we are now in a thundery stormy period and I can’t move forward on this job until I get a forecast offering 48 hours of dry calm weather.

Still, to look on the bright side, there are still lots of other jobs I can get on with so a change in strategy is called for. If I can’t paint the cockpit I’ll start polishing the combings and preparing the decks for an application of non-slip deck paint.