You can build your own boat using our plans and instructional videos! The 7th video in the FRS12 how-to build a boat series shows how to fiberglass the boat hull with epoxy resin. This includes laying fiberglass, wetting out the fiberglass, trimming fiberglass and applying fairing filler for easier sanding.
Before You Fiberglass the Boat
We’ve rolled the boat over and the bottom is a little wavy, so we’ve pulled it up and pushed it down where we needed it. Then we pulled thickened epoxy between our zip ties. Once the epoxy cures, we can take all the weight off, cut the zip ties out, and we’ll be ready to prep for glass.
Dry Fit the Fiberglass
We dry fit our fiberglass. Start by sanding the bottom and sides of the boat. We put a 1/4″ radius on the edges so our fiberglass will wrap over easier. To cut the fiberglass, we’re going to cut it six inches longer than the length at the shear, and we’re going to cut it a half inch to an inch longer than our widest dimension. The fiberglass will be longer at the front, so we’ll trim it. We marked ours with a sharpie and cut it with scissors. Just be careful not to nick the fiberglass and pull it apart, because that could show us as an imperfection later in the process you’ll have to work out.
Your edge at the shear bumper can over hang. This is a great way, if you’re unsure of where to cut it. We left it a little long at the shear bumper to make sure we don’t come up short. We can trim it off later when it cures.
The order that we’re applying the fiberglass is the same order we’ll apply it when wet. We’ll start with our sides and then move to the bottom.
So we have the other side on, cut the same way. Two inches of overlap at the front, four inches at the back. The bottom piece is already cut, so we’ll roll it out to show how that is.
The bottom piece of fiberglass will overhang the edges. Once it cures, we’ll trim it off. The reason for the overhang is to reinforce the edge.
We also have a six inch wide strip that goes down the keel and reinforces it, that gives us wear resistance. Both pieces of fiberglass overlap four inches at the rear.
Fill All Holes with Thickened Epoxy Before Applying Fiberglass
We have all the holes from the zip ties, and the seam from our plywood. We’re going to fill all of it in right before we fiberglass. I like to do it right before so that I don’t have to sand it. But, you can do it, let it dry, sand it, and then apply your fiberglass.
What we can do, is take an old shopping card, mix up thickened epoxy, and pull it through, packing it into the holes. Some will go through. We’ll clean that up on the other side when we flip the boat over. Don’t worry about it.
We filled all the holes and cracks in the whole boat with thickened epoxy. Now we’re going to cover the whole boat in epoxy in preparation for glass. We can use a chip brush or a foam roller.
How to Fiberglass the Boat
Now that we’ve covered the whole boat in epoxy, we can apply our fiberglass. We’ll start with the sides.
After it’s laid loosely in position, I’ll come back and work each area to get it to lay down exactly like I want it.
We finished apply the piece of fiberglass, and some of the areas wet through and some haven’t. We’ll take our brush or roller and apply another coat of resin.
The fiberglass is all applied. We have both sides, the bottom and the keel strip on. Let it get tacky. Normally it will take 1-3 hours depending on your temperature. Hotter temperature = quicker cure.
Flood Coat of Fairing Filler
Next we’re going to do a flood coat. We’ve mixed epoxy and added a microlight fairing filler. The purpose of the fairing filler is so you can sand the top of resin without sanding away the fiberglass. Using a chip brush, I’ll brush on a light coat to the entire hull.
The fiberglass is cured. We trimmed off the edges, sanding them smooth. Just be careful not to sand through the fiberglass. Now we’ll roll it over and start glassing the inside.