Use Fiberglass to Protect Your Boat

1. Tools

 

A disc sander with coarse discs for the rough work and medium discs for finish work. Large scissors for laying out cloth and a razor knife for trimming. For the application of the resin you may choose from a squeegee, brushes, or a roller. You will also need some solvent and detergent. Inexpensive gloves should be used to protect your hands.

 

2. Figuring Cloth Requirements

 

Measure the following dimensions:

 

A. The length of the hull around the gunwale line (or the length around the waterline if you are only doing the bottom).

 

B. The perimeter of the hull section at the point of maximum beam, measuring from gunwale to gunwale if you are doing the entire hull (or the point of maximum beam measuring from waterline to waterline if you are doing the bottom).

 

C. Measure the width of the transom.

 

D. Measure the depth of the transom. You ca n find the total area by inserting your measurements into this formula: (A x B) + (C x D). This will give you a suitable figure for ordering materials. The only change in this formula would be in the case of a double-ended hull where there is no transom. When doing your figuring, fractions of feet should be counted as a whole foot. It is always better to have a little extra cloth.

3. Surface Preparation

 

Remove all hardware, rails and moldings wherever practical. Strip the surface to the bare wood using a water rise paint remover, a sander, or scraper. Do not use a blow torch as it tends to drive the oils and paint into the wood. After all the paint is removed, rough sand the entire surface, as a roughersurface lends itself to betteradhesion. All cracks and seams should be filled with a non-oil base filler. 

 

If using Polyester resin we recommend a polyester based putty. If using Epoxy-Plus resin use our Epoxy Surfacing Compound.

 

4. Cloth Layout

 

Cut the cloth to follow the general pattern of the boat. If you are using more than one piece allow for a 2 to 3 inch overlapping. You will later feather this out so you need not worry about a ridge showing. Seal the hull surface with one coat of resin and allow to harden before applying the cloth. Next, the cloth is taped with masking tape into position before it is saturated with resin. This method allows you to fit your cloth carefully before the resin is applied. When applying the resin it is important that the cloth is thoroughly saturated. If you do not do this the cloth will not completely adhere to the plywood. When taping the cloth down do one edge very securely and the other edge loosely. If the cloth stretches while applying the resin you can quickly adjust it and pull it tight again. This method allows you to do a professional looking job your first time out.

 

5. Figuring Amounts of Resin

 

One gallon of Epoxy or Polyester covers:

4-3/4 yards of 38-inch wide cloth

3-3/4 yards of 50-inch wide cloth

3 yards of 60-inch wide cloth

A complete job requires 3 coats with the initial coat consuming the greatest amount of resin. Above figures include all three coats.

 

6. Applying Resin

 

Using a squeegee or roller apply the resin to the cloth, doing a small area at a time to be sure the cloth is completely wet out (no white spots) and all air pockets and wrinkles are eliminated. Have all your tools ready as you must work quickly before the resin starts to set up. When this coat sets up, apply another coat to fill the weave of the cloth for a smooth finish. Feather the edges that will be overlapped, e.g. the side and bottom cloth, with 60 or 80 grit sandpaper. Apply the remaining cloth as above.

 

7. Finishing

 

Sand any rough areas taking care not to sand into the fiberglass chopped strand mat cloth. You can do all your final sanding on the resin then apply K-Type Polyurethane paint directly to the hull. Or you can apply Epi-Prime epoxy primer as a sanding base, sand the primer smooth and then apply K-Type Polyurethane paint.