Monday, March 22, 2010

Fiberglass Tape, epoxy encapsulation

Yesterday was a bomber of a day.  Total Goat Island Skiff immersion.  Well over 14 hours of spanking.

Basically, I want to float test this boat.  My pond, frozen with several feet of New Hampshire ice iced out overnight.  I woke up two mornings ago to find that the ice cap had literally disappeared, and the boat was not ready.  So the hustle began.

First, I planed to fit a 3/8" poplar dowel for the the bow.  I scratched up the epoxy on the bow, scratched up the dowel, and stuck it on.  This will be glassed over with fiberglass tape.

I held it on with painter's tape.

Then, off to the races.  Taping the chines with fiberglass tape (FT) is easy, and kind of rewarding.  First, I measured the tape to fit the chine, and cut it off.  Then I slopped on some unthickened epoxy along the chine, and placed the tape along it, dabbing it down to hold it in place.  This tape has a "selvage" edge to it, which according to the plans should be removed.  Basically, its a plastic string that holds the fabric together, but it's a real pain in the ass to sand down, or so I am told.  It came out really smooth on the fiberglass I used for the blades, but on this FT it just mocked me incessantly.  So I said "screw it!" and glued it down with the edge on the bottom.  In case I couldn't sand it down at least it would partly hidden.  After the tape is laid down in position, I slopped on epoxy to wet it out and get it to stick.  Work from the middle to the ends of the boat.  Some gentle tugging got it in a good straight line and evenly over the rounded chine (round with a few passes of a plane and hit it with the sander).

 I did this to both sides, and the bottom/transom joint.  I'm not sure if the side/transom joint needs to be done or not, and I can always do that later.  The bow will be glassed when the epoxy has cured on the dowel and I can fair it to the hull.

After that came the fun fun job of spreading the epoxy on the bottom and the sides.  I did the bottom first while I debated how to do the sides.

 I did not pre-coat my panels because A: I wanted to see my boat! and B: I wanted to ensure the most effective gluing surfaces and I did not feel like taping their positions off.

In retrospect, the bottom was very easy, the sides a little more work.  I would suggest that any builder at the very least, pre-coat the outside side of the sides for simplicities sake.  Pouring the epoxy onto the sides and spreading it around was a little more of a challenge on the vertical surface, but due diligence paid off for a pretty neat job.

Back to that selvage edge.  After the epoxy had cured a bit on the glass, I decided to grab my utility knife and see if I could cut it off!  I could, and it worked awesome.  Pulling it out first before glassing would have been preferred, but this was the next best thing.  Holding the blade close to the edge I was able to get a nice clean cut down the the length of the hull, and then all I had to do was pull it up.

Presto!  As you may notice you can still see the weave in the FT.  This weave took a lot more work to fill in than the glass on the blades.  On the suggestion of my compatriot in Sacramento, I threw on two coats of slightly thickened epoxy and it filled it in much better than the straight undiluted stuff.

Here's a before and after:

A long day, but worth it.  A float test is quickly looming in my future!


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