Step 5: Applying the Fiberglass Jelly
Your transom is ready for some light sanding and then a copious amount of fiberglass resin (Jelly) Go along the edges with a palm sander (you manly men can hand sand if you like) try and level up all your edges and remove excess glue that seeped out from the edges. Clean up the wood and remove dust and lay it flat on some newspapers for the first application the fiberglass resin. I used a piece of cardboard for mixing; put down the recommended amount of resin and apply the pea sized amount of cream hardener. Mix it as briskly as possible with the applicator and start applying it to the transom making sure to get the sides and cover all exposed wood. Don't worry about getting it perfect, we're going to be sanding this bad boy once it cures. After the first side is complete, let it cure overnight and flip it over and do the other side.
One thing I noticed is that the ridges are rather hard to sand, this stuff hardens up nicely. I didn't spend too much time trying to make it smooth since it wasn't going to be exposed in my boat. Once you have it sanded to your liking you're going to try and get it back to where it belongs. It took some time for me since I added the extra Â½" layer to it. If you stuck with the original thickness, you should be okay. Now that it's in place break out the wood clamps again and clamp it into place, use as many as possible since your drill force is going to be pushing against it.