The equipment used for applying the finish can make a difference to the success of your project. Guidelines for the best equipment to use are always detailed on the paint can and if a particular type of brush or roller is required, it will be specified. Further details are available at yachtpaint.com, however, this section should give you a few pointers.
When removing old paint, a scraper should be used. Keep the tool sharp. A good idea is to round off the corners to minimize the risk of gouging. A "dragging" type is usually more controllable than a "pushing" type.
When sanding, the amount of paper you will use will vary enormously. A very approximate guide would be one sheet per square yard of bare substrate, such as wood or fiberglass. It is always better to use a sanding block to achieve a smoother surface. For previously painted surfaces, half a sheet per square yard is a rough guide and rubbing down between coats will use a similar amount.
* ANTIFOULING MUST ONLY BE WET SANDED.
A suitable stirrer will be needed to stir the paint prior to use; an old screwdriver is not suitable for this job. A pallet knife or stirring stick is best. Remove surface dust with a cloth dampened with the thinner that will be used in the paint. The area to be painted must be masked off using a high quality clean edged tape. There are two types available; paper masking tape which is suitable for antifouling, and high performance tapes, which are suitable for topside finishes and will prevent creep.
It is always important to use a good quality brush, which is as large as you can comfortably use. A good brush is a good investment, which should be thoroughly cleaned after use.
Generally, a solvent resistant 5/16" or 3/8" nap roller can be used for antifouling application, and a small cell foam roller for high gloss topside finishes.
Application of all paint products by spray requires specialist equipment. When spraying two-part products an air-fed mask must be worn. Spraying of two-part polyurethane products is not advised without using a positive pressure air-fed hood.
All paints are designed to allow application of the correct wet film thickness when applying the recommended number of coats. This is obviously only a guideline as different people will apply different thicknesses depending on their technique or the equipment used. Problems of over-application can occur, but these are minimized by ensuring the correct over coating times are adhered to by ensuring the correct quantity of paint is applied as calculated using the coverage chart at the back of this manual, problems of underapplication should also be minimized. As already stated, the application method you choose will have a direct effect on the amount of paint that is applied in each coat. A rough guide to the amount of paint applied by the different methods is as follows:
|APPLICATION METHOD ||AMOUNT|
|FOAM ROLLER ||1-1.5 MILS (20-40 MICRONS)|
|MOHAIR ROLLER ||1-2 MILS (20-50 MICRONS)|
|BRUSH ||1-2.5 MILS (20-60 MICRONS)|
|CONVENTIONAL SPRAY 1-4 MILS ||(30-100 MICRONS)|
|AIRLESS SPRAY ||2-8 MILS (50-200 MICRONS)|
1 MIL = 25.4 MICRONS 1 MIL = 1/1000TH OF AN INCH
Original article from Interlux