When applying fiberglass to a mold, the mold must be prepped beforehand. Prepping the mold includes filling all holes, then sanding and polishing the surface with a liquid sandpaper. Liquid sandpaper is available at local home improvement centers or from Internet sites. The process is time-consuming but not difficult.
Instructions
1. Place the fiberglass mold on a flat work surface.
2. Sand the surface of the mold with 320 to 400 grit wet sandpaper. Saturate the sandpaper with water. Sand the surface with a circular motion to remove all scratches and knicks. Let the mold dry completely before continuing.
3. Fill all holes and knicks with modeling clay. Feel the surface and make sure the clay is flush with the mold.
4. Open the liquid sandpaper. Place the lint free cloth over the opening and tip the bottle to saturate a portion of the cloth.
5. Apply the liquid sandpaper to the entire surface of the mold using small circular motions. Let the liquid sandpaper dry for the required length of time. The time will vary depending on the temperature and humidity of the area.
6. Wipe the liquid sandpaper from the mold surface using small circular motions. Rub your hand over the surface and feel for any imperfections. Resand as needed.
7. Prepare the resin with the catalyst according to the instructions. Each resin requires a different amount of catalyst. Read and follow the directions.
8. Cut the fiberglass mesh into workable lengths. The pieces should be approximately 2 inches wide and 6 inches long.
9. Submerge the fiberglass mesh in the resin. Immediately place it on the mold. Smooth it into place with your hands. Continue the process until the mold is covered. Work quickly so the resin does not set up while completing this task.
10. Immediately roll the surface of the fiberglass to the mold. Look for light areas beneath the surface of the mesh. Roll the area until the light spot or spots disappear. These areas contain air. They must be removed or a hole will appear on the finished fiberglass piece.
11. Give the fiberglass 10 minutes to set. Tap the edge of the fiberglass that extends past the edge of the mold. Check to see if it is starting to feel like a piece of cardstock. If so, this is a semi-set stage. If not, let it sit another three to five minutes, then check again. Repeat the process until the fiberglass is set far enough to trim.
12. Place the blade of the utility knife perpendicular to the edge of the mold. Cut through the semi-set fiberglass to create a straight edge.
13. Let the fiberglass piece dry completely before removing it from the mold. This will take one to four hours, depending on the thickness of the fiberglass, the temperature and the humidity of the area.
