Epoxy work on seats sheer and Zip parts

The last post left off with my having cut out a piece of Meranti for the rear seat. This weekend, I laminated that onto the A/C exterior plywood... and did a little more epoxy work along the way.

1/4" Meranti top for the rear seat

Just as Id done with the front thwart, I coated both mating sides with epoxy (not thickened), and held them together with concrete blocks and weights while the epoxy cured. I had just enough epoxy left over to also add a 2nd layer to the Zip transom knee.

Laminating the Meranti onto the rear thwart. I used the extraneous epoxy to encapsulate the underside of the front thwart, as well as the transom knee for the Zip.

Regrettably, however... after the epoxy cured, there remained a small gap.

And a dust bunny got stuck in the epoxy on the Zip part.

All this didnt go perfectly according to plan. After the epoxy had cured, I found a gap between the two layers that would need to be filled. Also, some dust had gotten stuck in the epoxy on the Zip transom knee. I am trying for substantially better fit and finish on the Zip, so I sanded off the dust bunny & planned to encapsulate with a third layer.

Logistically, I thought it best to encapsulate the undersides of both seats next. This would be the 2nd coat for the forward thwart. I planned to tilt the rear thwart just a little so that epoxy would run into the gap and fill it. Since I havent trimmed the Meranti top yet, this should help the epoxy flow down into the gap. With the extraneous epoxy, I planned to encapsulate the underside of the sheers on the aft third of the boat, as well as the Zip part.

I ended up having more left over epoxy than expected. So after quickly cleaning them off, I also encapsulated part of the Zip stem and the forward face of frame 5-1/2.

More encapsulation; trying to fill the gap on the aft thwart. Here it is propped up slightly with a scrap of mahogany left over from the quarter knees.

Epoxy drying on the Zip stem & frame 5-1/2.

Current Status of Zip Parts
Part	Status
Stem & Breasthook Assembly	Most surfaces have 1 coat of epoxy
Frame 5-1/2	Forward face has 2 layers of epoxy. Other surfaces have 1 layer.
Frame 4	Side members cut, but have not been planed or notched for sheer.
Transom Knee	Coated with 3 layers of epoxy
Transom	Side frame members cut 1/4" oversized on outer side. Have not been planed.

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Minor epoxy miscalculation turned out fine

One of the wisest investments Ive made in this whole boatbuilding project was the $30 I spent on a kitchen scale at K-Mart. My "close calls" with epoxy miscalculation basically evaporated.

That is, until yesterday afternoon.

Something I didnt mention in yesterdays post, was that when I ran out of epoxy, Id upturned the resin & measured out 144 g. Silvertip epoxy, measured by weight is mixed in a ratio of 1 part resin to 0.44 parts hardener.

Heres a photo of the kitchen scale Id purchased at K-Mart.

Taking the 144 g of resin, and multiplying it by 1.44 meant that I needed to add hardener until the overall weight equalled 207 – 208 g. (144 x 1.44 = 207.36).

So, I upturned what was left of the hardener into the mixing cup. Unfortunately, the combined weight had only reached 194 g when the hardener ran out completely. I was 13.36 g short.

Marine epoxy is expensive. "Besides," I thought, "Ive had closer calls than this with estimated measurements." I decided to mix it for 3x longer than I usually do (6 minutes, since I usually mix for 2 minutes), and then just use it.

It worked just fine.

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