Epoxy Fillets and Taping Seams.

Dry-fitting one of the deck beams. This will not be installed till after all the seams have been glassed.

I'm getting to the stage where it's tempting to start doing things out of order like starting the interior framing. But first, it's important to get all the seams fully joined by gluing them together with a mixture of thickened epoxy and fiberglass tape. This can be really nasty work, and it's important to take some time to set up a good work space and have everything you will need in place before mixing any epoxy.

The basic plan is to wet out the seams with unthickened epoxy to let it penetrate the wood, then adding the thickened mixture on top to create the fillet. Some people like to do the fillet and glassing all at the same time right on top of the wire stitches. Instead of doing everything at once, I'm laying down a thin fillet first and letting it set up enough that I can remove the wires, clean up the seam a bit more easily, then add the fiberglass tape. Doing it this way also lets the seam get strong enough that I can get in the boat and do the final glassing up close. I hoping this will make for a cleaner seam.






At first, I was just applying the thickened epoxy with a small drywall tape knife and then smoothing it with a rubber squeegee cut to the right shape. But that didn't work too well and eventually I ended up putting the thickened epoxy in a small baggie with a corner cut out and squeezed it into the corners. It's kinda like piping icing onto a cake. That worked and only required a tiny bit of work with the squeegee to get a nice rounded fillet.

I did have some trouble with always getting the same consistency of thickness in the epoxy mixture. Even though it looks plenty thick in the mixing cup, it's important to lift a gob of the stuff out of your mixing cup and make sure it does not run at all. Otherwise you end up with a fillet that sags when you aren't looking.



Damned saggy fillets....



After the fillet has set, the stitches can be removed by applying a bit of heat to the wire long enough for it to soften the epoxy enough to pull the wire out. I have found that nippers are the perfect tool for this, but vice grips work pretty well too. I think I get a better finished seam this way, but it takes a bit longer. I've been waiting for the fillets to set up but not fully cure (18-24 hours or so) to remove the wires. Most of them just pulled out easily with some pressure from the nippers, but a few were a bit more stubborn. For these I pulled out the soldering iron and let them warm up for a minute or so, then they slide out no problem. Of course I hear that there is a much faster way to do this. Where the soldering iron takes 30 second to a minute, the quick way is to get a car battery and some jumper cables. Okay, at this point I'm thinking some gloves and eye protection might be a good idea too. Then, just hook the negative to one end of the wire and touch the positive to the other side and voila, instantly hot wire. Leave it there a bit longer and it might look like this.

This is Andrew Linn's Laguna Sinko after this year's Texas 200. The boat was built on the beach just hours before launching and was always intended to be sailed for one event and then used for a bonfire. Some Say Andrew is crazy, but not me. Not out loud....

I'm not sure who took the picture, but it's reported from the Duckworks Texas 200 Special Report page.

Once I got all the wires out I added a bit more thickened epoxy to the seam and laid on a couple layers of 10 oz. fiberglass tape. The key here is getting the tape fully saturated before applying it to the seam. I just set up a wide flat board with some freezer paper on it to lay out the glass tape. I then pour some epoxy on top and squeegee it around till all the weave is saturated. Then I add the next layer right on top and wet it out as well. Then I take the pre-soaked tape and gently lay it into to the filleted seam and use the squeegee to slowly work any bubbles of air out the side of the seam. If I need to, I will add a bit more unthickened epoxy to the tape to make sure none of the weave is left dry.

Most of the seams I'm working on right now will be hidden in the closed section of the boat so I'm not getting too concerned about them looking perfect. Hopefully I'll have my technique dialed in by the time I get to the seams that will show in the completed boat. One thing I'm considering is laying down some of the plastic coated freezer paper as a release film on top of the final layer of glass and squeegeeing on top of that to give a smooth finish without having to add an extra layer of fairing mixture.



It's hard to get pictures when your hands are in surgical gloves covered with epoxy. Marie will be taking more pictures as I'm at it tomorrow and I'll add them here soon.