Painting Tips

HOW TO PAINT PREVIOUSLY PAINTED BOAT BOTTOMS

The difference between an amateur and a professional painter is preparation. The amateur focuses on painting while the professional puts most of his efforts into preparing the boat for painting. It's a cliche, but it's also true, that 99% of a good paint job lies in the preparation. It doesn't matter if the boat is wood or fiberglass, prep work still has to be done. This job on both types of boats starts with removing all hardware, ventilators, bang irons and decorative name plates.The condition of any existing coating is important in order to provide a sound surface for your new antifouling. If the paint is in poor condition, remove it with Marine Strip Pro.

KNOWN ANTIFOULING Check for compatibility.

1) Remove all traces of loose paint, dirt, grease and other contamination by wiping with Dewaxer. Sand with 80-grit sandpaper. Remove sanding residue.

2) Apply 2-3 coats of antifouling paint.

UNKNOWN: PRIME BEFORE PAINTING If you do not know what the old antifouling is on your boat, it is still easy. Use Bottom Protect Primer.

1) Remove any loose, flaking areas with a scraper. Sand with 80-grit sandpaper. Rinse with fresh water and allow to dry before applying the new antifouling. If the old coating is in poor condition it is advisable to remove it. Apply Bottom Protect Primer directly to the old antifouling.

2) Apply 2-3 coats of antifouling paint.

UNKNOWN: REMOVE If the old paint is in poor condition remove it. For removal, use Marine Strip Pro. It’s compatible with your valuable fiberglass hull and can remove several coats of paint in one application. After stripping, you are ready to prime and paint your newly cleaned hull.

CONDITIONS

Temperature As painting can take place over a wide range of temperatures, you may need to adjust the drying and curing times quoted. A good guide is to double the drying/curing time with a drop of 10oC and halve the time with an increase of 10oC (adjust accordingly between these temperatures).Paint properties change with temperature variation. At lower temperatures paint thickens and may need thinning (always note the correct/maximum thinner ratios and take care not to add more than is recommended). Avoid painting above maximum recommended temperatures as the faster drying/curing rates of the paint reduce the flowing properties which can result in visible application marks; this can also occur when painting in direct sunlight where the surface has a much higher temperature than the ambient (surrounding) temperature.Check minimum application temperature of the paint you are using as the paint will not cure below this, which will result in poor film formation, poor adhesion between coats and unsatisfactory gloss finishes.Relative Humidity Ideally relative humidity should not be above 65% (this is measured with the use of a hygrometer). A good test is to moisten the surface to be painted and if it dries within 10-15 minutes, it should be all right to paint. Outdoor painting should not take place too early or too late in the day when there is a risk of condensation or dew.Ventilation Painting indoors Make sure there is plenty of ventilation to allow the paint solvents to evaporate and the paint to cure properly and avoid blistering.Painting outside Choose a day with calm weather to minimise the risk of dust pollution on the paint surface and to allow solvent based paints to flow out naturally, which will improve the final finish.Suitable clothing/protection Make sure you have suitable protective clothing to wear, including gloves and glasses.Products Dewaxer Bottom Protect Primer Bottom Paint