Building Guppy - Part 4  
by Steven Lewis - Souix City, Iowa - USA

Part 1 - Part 2 - Part 3

Winter is over, Spring is here and the epoxy is flowing...sorta. I went out to start filleting the hull and found this:

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My resin had partially crystalized! Not to panic...I poured/scooped a bunch (10-12 oz) into a plastic container and headed for the house. 3 30 second shots in the microwave and a couple of 10 seconders and voila...

 

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Nice clear and smoothed resin. If you try this, make sure to stir between nukings and only warm the resin to about 90°. The next bit to do is to...

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Cut the strips for taping the seam. Having no 4" tape on hand I had to cut them from some 30" wide cloth that I have. No big deal, just overlap the joints a bit. Next we mix up a batch of resin and...

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Prewet the seams. This is so the wood has enough resin and that it doesn't leech resin out of the filleting putty, which is dry enough already. Once the whole seam is wet...

 

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Mix up a batch of goop. I actually made this before I mixed the wetting out resin, and it hadn't oozed off the side at all. This is the right consistancy for what I want. I used about 90% wood flour and 10% cabosil (fumed silica). Anyone who is worried about woodflour absorbing moisture...think about it. This is the ultimate in encapsulated wood celulose. If this ain't waterproof, none of it will be! So anyway...

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I slapped some in there, nice and thick. I know it isn't pretty but it is just the second layer and will be smoothed out with...

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A small brush and the rest of the raw epoxy from wetting the wood out. Use a medium amount, enough to smooth the biggest lumps and ridges out and feather the fillet into the wood. This also helps to start wetting out...

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The fiberglass strips. Lay the strips into the fillets and press into place but not too hard. You should wet the wood around the fillet so the tape sticks well the full width. Whip up another batch of resin and ...

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Wet out the cloth completely. The extra width of wet wood is just using up my extra resin. I will be putting a coat on the inside to seal the wood anyways. This will be good enough for the bilge so this seam is done. Total elapst time not including cutting the strips was about 1/2 hour. This method of doing the filleting and taping creates the strongest joint because all the epoxy is 100% bonded together chemically and mechanically. If I were to fillet first then sand and tape, not only do I have the extra work of the sanding, but I would only get a mechanical bond between the two layers of epoxy (fillet layer and tape layer).

Stay tuned for the next installment