Today I did the big job of fiberlassing the interior of the boat’s bottom. (See video posted below.) This started with flipping the big panel up-side up and then removing all epoxy squeeze out from the seam using the same method of block plane then power sander that I used on the puzzle joints. There were a few small voids in the seam which I filled with epoxy thickened with wood flour. It is important to fill any holes or gaps which could create an air pocket beneath the fiberglass. Air space beneath the fiberglass will create a weak spot which will certainly break and be followed by moisture intrusion and fiberglass delamination. As a rule, if you can put your fingernail into it, fill it!

Next I put tape around the perimeter to cover the rabbet and protect it from being filled with epoxy drips which will need to be sanded off later. This is a great way to protect adjacent panels or joints when fiberglassing, but be sure to remove it the same day, when the epoxy has stopped being sticky but is still not hard. If left until tomorrow it can cause more work than it saves. It is very difficult to remove blue tape that has been epoxied on. Plan your work day carefully.

Next I rolled out the fiberglass and smoothed it out nicely. Then wetted it out one red cup at a time. (Again, see the video.) I will stress it again, that it is very important to keep your unused fiberglass cloth clean! If it comes folded in a bag, fold the unused portion back up an put it in the bag. If it comes on a roll wrapped in paper, wrap it in paper when you have finished cutting the amount you need. Don’t let it touch the floor! It will pick up everything which will end up under the fiberglass when you are laying it up, causing air bubbles that will need to be cut away later. Also, be careful of anything that has wet epoxy in the shop. It is impossible to tell you have gotten a small amount of epoxy on your unused fiberglass until you are trying to wet it out on a project and a spot will not go clear. Protect your fiberglass at all times.

I am hoping to make this thing look like a boat tomorrow, so I also glued the strakes to length. These puzzle joints fit much more loosely, so I decided to stack the pair of panels and weigh down the joint with heavy weights. This is a really nice way to glue these types of joints, but you must make sure that you DON’T FORGET TO PUT PLASTIC IN BETWEEN THE TWO SIDES! It is easier to forget than you might think, and if it happens, the two stacks will be epoxied together and they will likely be destroyed trying to get them apart. Yes, this has happened to me.

Lastly, I trimmed the edge of my earlier fiberglass job with a razor blade. This is best done a few hours after fiberglass is applied. (Sooner in a hot shop.) The epoxy will be no longer sticky, but still flexible, and cutting the excess glass will be easy. This is also the time to remove any blue tape.

The plans call for a fill coat over the fiberglass, so I finished the day rolling on an epoxy fill coat onto the fiberglassed surface. This is a good way to keep the project moving forward without sacrificing an entire day to do only an epoxy coat. It can only be done after the previous coat has stopped being sticky, and it will not negatively affect curing.

All gaps filled with epoxy thickened with wood flour and blue tape applied to protect the rabbet from epoxy drips.

Fiberglass laid out and trimmed. Always trim the overhanging edge to less than 3" to avoid a bubble being caused at the edgbe due to the weight of hanging fiberglass cloth. The second, overlapping layer is folded safely out of the way after trimming.

Finished fiberglass! The weave of the cloth should be distinctly visible and the cloth should be laying flat onto the surface with no bubbles. All puddles should be removed by using a plastic spreader to pick up material and scraped back into the red cup. My friend Nick Schade cuts a little slit into the side of the cup and scrapes his plastic spreader off by inserting it into the slit and pulling it through, which scrapes off both sides of the spreader at once. I think it is a great idea, but I never think of it until AFTER I am too covered in epoxy to touch my scissors.

The strakes being glued to length using heavy weights and boards wrapped in plastic to hold them together flat. These are stacked, which is a good way to do multiples of identical panels. But DON'T FORGET THE PLASTIC IN BETWEEN!

Another view of the joints being glued. You cannot possibly have too much weight.

Fiberglass trimmed and fill coat complete! Plastic on the floor is essential. Fiberglass is a messy job. Wear old shoes!