Tuesday, May 22, 2012

Glass Tape Success

The last time I worked with fiberglass tape on my brother's Bolger Teal build, it was a complete debacle.  We ended up with kinked, gappy glass that really wasn't doing the joint any favors; after getting about 20% of the chines done, we abandoned the glass tape all together.  So it was with some trepidation that I began taping the fillets on my Melanesia.

Surprisingly, it turned out really well, and I was able to do all three fillets in a single 90-minute session.  I was using a cheap disposable paint brush (bristles, not foam) and unadulterated epoxy.  Here's the process:
  • Cut a piece of fiberglass tape to the proper length for each section.
  • Mix a small batch of epoxy, so it doesn't thicken before you get the chance to use it all.  
  • Brush epoxy over one section of fillet and the surrounding ply, a little wider than the width of the tape.
  • Apply the tape to the fillet.  Get the position right, then press the tape into the epoxy.  
  • Smooth it out with gloved fingers, being careful to press it firmly against the fillet and wet it out thoroughly.
  • Brush more epoxy over the cloth until it looks uniformly wet and transparent.
  • Repeat for the next section of fillet, mixing more epoxy as necessary.
Looking back at our bad experience on the Teal, I think the difference lies in the smooth fillets.  We were trying to glass a sharp corner on a curved line, and the glass just didn't like taking that shape.  It was like folding paper - you can bend paper, and you can crease it, but you can't bend creased paper.  So the glass wrinkled. 

The glass will all but disappear when it gets
a couple more coats of epoxy over it.
The fillets are smooth curves, and the curve of the chines are smooth as well, so the Melanesia doesn't ask the glass tape to do anything it can't do, and the process is much easier.  But I am glad I put in all that work to get the fillets ready.  I suspect it would have gone badly if I'd been trying to glass over the undulations and lips they had before the sanding.

When the epoxy is set but not entirely cured, I'll brush another coat or two over it until the weave of the cloth is completely encased.  And just like that, the interior fillets will be done.

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