Putting a water-based bottom paint (WBP) over a solvent based primer can be done with some modified application procedures. You do NOT want to make the window, or hot coat the water based paint over the solvent based primer such as Tuff Stuff high build marine epoxy primer. If you do, it will mud crack. So instead of putting on the WBP over the Solvent Primer in the same day, you need to wait for the primer to totally cure. Then you have to sand it with 80 grit sandpaper before apply WBP. This is a lot of extra work and very difficult to sand = extremely hard surface. So the best thing to do when using a high build solvent based epoxy is to coat it with a solvent based paint. That way you skip the extra time and labor with sanding.
Awlgrip Topcoat is a polyester based high gloss polyurethane topcoat giving long lasting gloss and color retention. It is considered the among the best Topside Paints in the marine industry. AwlGrip Topcoat may be applied by brush/roller or spray. For application above the waterline only. See Awlgrip Application Guidelines
The most common practice for the do it yourselfer is priming the boat with Awlgrip 545 epoxy primer. This is a 2 part primer, so you will need the base (either white or grey) and the converter. Awlgrip also recommends a reducer. The links to the converter and reducer can be found on the base primer product page.
Mixing and Reduction:
This is a two part system. You must order the base primer in either gray or white along with the D3001 Converter in the appropriate size. The mix ratio is 1:1 so if you purchase 1 quart of primer you also need 1 quart of converter for a total of 2 quarts. Additionally you need to purchase the appropriate reducer (spray or brush) for spraying reduce up to 25% with T0006 and for brushing reduce up to 10% with T0031.
Theoretical Coverage: 497 Sq feet/gallon at one mil dry (25 microns) 165-248 Sq. Feet at recommended dry film thickness. Calculated based on a theoretical transfer efficiency of 100%.
Mixing and Reduction
Spray: Mix by volume one part AWLGRIP Topcoat Base Component (Color) with one part AWL-CAT #2 G3010 spray converter to a a smooth homogenous mixture. Reduce up to 25% with the spray reducer(s) appropriate for conditions. Overall mixture is 1:1:1/2 volume. Example: 8oz Base, 8oz G3010, 4oz Reducer. 25% reduction is a standard mix. Clear coats. metallic colors, and painting in high temperature conditions may require additional reduction. 40% reduction is the maximum recommendation.
Brush/Roller: Mix by volume two parts AWLGRIP Topcoat Base Component with one part AWL-CAT #3/H3002 Brushing Converter until one smooth, homogenous mixture is obtained. Reduce 25% to 33% with T0031. Overall mix is 2:1:3/4-1 by volume. Example: 8 oz. color base component, 4 oz. H3002, 3-4 oz. T0031.
Brush/Roller Application: 700-725 Sq. Feet at 1 mil (25 Microns) dry: 285 Sq. Feet at recommended dry film thickness.
Recommended Wet Film Thickness: 4.5-6 mils (112.5-150 Microns), Total of 2 Coats.
Recommended Dry Film Thickness: 2-3 mils (50-75 Microns), Total of 2 Coats.
Spray Application: 530 Sq. Feet at 1 mil (25 microns) dry film thickness; 210 SQ. Feet at recommended dry film thickness.
Recommended Wet Film Thickness: 6-9 mils (150-225 Microns), Total of 2-3 Coats.
Recommended Dry Film Thickness: 2-3 mils (50-75 Microns), Total of 2-3 Coats.
You can view the links provided above to see more information about the products, mix ratios, surface prep and auxiliary products.
Fiberglass is what is used as the base of the boat. These are the strands underneath the gelcoat that you typically do not see. (unless there is a gouge!) Over the fiberglass usually gelcoat is applied at the factory. If the surface is scratched gelcoat is the same color throughout; if the surface has been painted when scratched it will show what is underneath.
Need a repair?
If it is just a gouge and not penetrated all the way through the boat, then you would need to fill in the gouge with 3M premium marine filler (just one product that will work but our most popular for this use). After you have filled in the gouge and sanded it down, you would then apply the topcoat of gelcoat. (gelcoat is the top finish that you see on your entire boat.) Gelcoat is typically much thicker than a paint and is designed to protect the underlying fiberglass as well as provide a smooth shiny appearance. Be sure to leave the marine filler about 1/8″ lower than the surrounding gelcoat. This will allow you to apply enough gelcoat and be able to feather the surrounding area once your done. If you leave the marine filler flush, then once you apply the gelcoat you will have a lump on the area you are repairing (gelcoat should be thick enough or it could release from repair).
Here are the products that you would need.
The amount that you will need is dependent on the size and number of gouges. If you have many gouges, you may consider buying a quart of gelcoat. However, the nice thing about the gelcoat repair kits is that they come with tints so that you can try to match your existing gelcoat color.