Mold Repair:

Repairing Punctures

The following are recommended procedures when repairing punctures that penetrate into the laminate:

Equipment needed: A power grinder with 16 grit disc, cardboard for mixing, solvent, fiberglass material, catalyst, resin, brush, roller, marine grade bonding putty, orbital sander with 80, 120 and 320 grit sanding paper, powered drill and driver, stainless steel screws, safety glasses, mask and gloves.

1. The problem with patching a puncture is joining of the old material and new material. Therefore, it is very important to follow proper procedures.
2. Remove the damaged fiberglass material from the defective area using a power grinder and a 16 grit disc. Feather the area away from the center of the puncture. Grind deep enough to remove all defects.
3. After grinding wipe the area clean with a rag and solvent, removing all dust and contaminates.
4. Use as many plies of reinforcement as equal to the original laminate. Cut the fiberglass to the shape of the hole. Cut the pieces to get progressively larger.
5. The first layer should extend to the outer perimeter of the ground area. All succeeding layers should end with the smallest material in the center of the repair. Work out all air bubbles with a roller or brush.

Both the front and back sides of the area should be laminated with fiberglass material.

In critical areas where loads are high, the following procedure is recommended.

1. Make the repair as discussed above. After half the material is applied, use a battery powered drill and drill holes through the wet laminate into the old laminate at even intervals. Using a battery-powered driver, drive in stainless steel screws, insetting the screw heads. Continue the material build up. Work the mat and woven roving around the heads of the screws. Let the repair cure.
2. Remove the excess fiberglass and restore the original contour to the area with an orbital sander and an 80 grit disc.
3. Apply a marine grade putty or resin based milled fiber putty. Catalyze the putty and mix thoroughly so no uncured spots will occur in the patch.
4. Use a squeegee at an angle to flair-out the putty and fill in any indentations in the patched area. Allow the putty to cure.
5. Remove the excess putty. Contour the area by sanding with 180 - 220 grit sandpaper. If the initial sanding is done with an orbital sander, sand the putty down until it is not quite equal, with the surrounding area. Finish the sanding process with a sanding block to restore the surface to its original contour. The sanding block should exceed the width of the repair.
6. If dips or pin holes appear after sanding, re-putty, cure and sand again. Use a straight edge to check for a straight, contour before re-gelling.