Surface preparation Surfaces to be painted must be clean, dry and free of oil or grease.Bare surfaces must first be primed with a suitable priming scheme, filling betweencoats with an epoxy profiling filler to make good any undulations.Existing anti-foulings don’t usually need any special preparation, but they can belightly wet sanded to remove small lumps and ‘blebs’ in the paintwork.Anti-foulings must never be dry sanded or burnt off with hot air strippers, as evenat the end of a season they will contain toxic chemicals. So wet sanding with fresh water is the only safe answer.Apart from being safer, the lubricating action of the water means that the jobwon’t take as long as you might expect.Propellers can be cleaned with a power drill and wire brush to give a smooth polished finish. The copper in bronze propellers usually keeps most fouling at bay, but a couple of coats of Peller Clean or Seajet 034 anti-fouling can be used in areas where heavy fouling is a problem. Finally, wash everything down to remove dust.
Applying marine primer Applying Anti-fouling Priming the underwater hull If possible, apply your anti-fouling during late morning or early afternoon in calm, dry weather. Don’t antifoul too late in the day, especially when skies are clear, as the rapid fall in temperature will encourage overnight dew, which will spoil your newly applied paint. Surface moisture when painting will also cause loss of adhesion and peeling.Apply a good quality masking tape around the waterline, and marine mask off anodes,shafts and fittings to protect them from unwanted anti-fouling. Osmosis is a common problem on glass fibre boats, and is not usually seriousunless the hull is very badly blistered. Small, localised blisters can be often treated by drilling them out with a countersink drill, and then filling the holes with epoxy filler; although this will not provide a permanent cure.Widespread blistering, or large swellings in the gel coat are a more seriousmatter, and should be dealt with by a professional. On bare and filled areas, you’ll need to apply touch-ups of primer to ensure good adhesion of the following coats. For a high performance epoxy primer, use Seajet 117 or 118 Epoxy Primers. This is particularly recommended when all the existing paint is removed and full coats of the primer system are required. Seajet 2-pack Multipurpose Epoxy Primers are also designed to seal prepared gel coat on glass fibre boats and is ideal for using on metal keels.However, for small areas of touch up, or if a single component primer is preferred, apply Seajet 011 Underwater Primer. Observe the correct over coating intervals between each coat – this information is on the tin. Use a brush for small areas or a roller for large areas. But will Seajet anti-fouling be compatible with any anti-fouling that is already on your hull? In most cases it will be. However, there are certain Teflon based anti-foulings, which need to be removed beforehand.If you don’t know what anti-fouling was last used on your boat, or the condition ofthe boat is not ideal, the best solution is to apply a full sealer coat of Seajet 011 Underwater Primer. This will give good adhesion to the following coats
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