Day 9

5/14/2012

mar·a·thon: something (as an event, activity, or session) characterized by great length or concentrated effort.

Tonight's session could truly be characterized as a marathon and by the end my back was absolutely killing me from so much bending. This is because my second set of saw horses which the deck was resting on (store bought) are too low, so I hope to finish up with those and never have to use them again.

I began by removing all of the stitches and the temporary forms. The tack welds are sufficient to hold the boat together and in its current and I don't want them in there when the fillets harden, so they have to go. I used wire cutters to snip the stitches on the inside and pliers to pull them free.

At the bow and stern, where I had previously applied fillets, the wires were trapped in epoxy. To loosen these up I heated the wire with a butane torch to loosen the epoxy then used the pliers to pull the wires free. There were only two wires at each end of the boat which would not come out using this method, so I just snipped those off flush and sanded them down smooth. They will be in the area that is getting epoxy and graphite so they will be invisible.

After removing all the wires from the hull I then moved onto the deck. Here are both halves of the boat sans stitches.


Since I was working under time constraints because I didn't want the epoxy fillets to cure before the glass was wetted out, I went ahead and laid out and trimmed the fiberglass tape for all the joints ahead of time. I also measured and cut the fiberglass cloth for the cockpit at this time. This turned out to be a really good idea, but more on that later.

Time to fillet the joints. The purpose of the fillets is to fill up the seams so that the fiberglass tape makes a smooth transition across the gaps. All of the strength comes from the fiberglass. You don't want there to be any gaps or sharp folds in the fiberglass when it gets applied or these areas will be weak. The manual from CLC shows the fillet material, a thick mixture of wood flour and epoxy, being squeezed out of plastic zip top bags like a pastry bag. The only problem with this is it creates unnecessarily large fillets which adds weight without adding strength and it consumes more epoxy which isn't cheap. I chose to adopt the methodology of László I. Mórocz for smaller fillets. the manual says you will need to refill your pastry bag three or more times, but I only needed two batches of fillet material and I had a good amount of the second batch leftover.


Because the weather is warm now, I mixed small batches of epoxy, 15 pumps per batch, and wood flour, just enough to make a peanut butter like consistency. I then used my fillet tools which I purchased from CLC to press the fillet material into the sames of the hull and the deck. CLC's manual does the filleting, glassing, and sealing of deck and the hull separately, but this is messy work and my philosophy on messy work is it's better to do it all at once rather than dragging it out, so I did both at the same time (see the definition of marathon above).






Once I pressed the material into the joint I then came back and scraped the excess off the edges of the fillet with a used department store gift card. These make perfect scrapers because they can be bent to conform to the area you are scraping while avoiding touching the finished fillet, plus they don't cost anything so when you are done you just toss them in the trash.


Although it's not in the manual, I went also applied a fillet around the underside of the hatch assembly. This probably was unnecessary since no glass goes around this area, but I figured it couldn't hurt and would help assure a good seal around all those exposed plywood edges.






Once all the fillets were in place and cleaned up, I rolled out the pre-cut fiberglass tape over all of the seams.








I mixed up a batch of epoxy with no thickener and used a bristle brush to spread it over the fiberglass tape. You don't want too much epoxy here, just enough to make the tape turn clear, anything more is just extra weight with no extra strength.





Once I had some epoxy on the tape it was pretty easy to make adjustments using my fingers. The most challenging area to get the tape smooth was in the bow where the sharp upward curve made the tape fold. I had a similar problem at the stern. In order to get the tape to lay flat I ended up cutting about 1/2" into the folds and overlapping the edges of the cut.

(Sorry there are no pictures of this process, but my hands were absolutely covered with epoxy so I couldn't pick up the camera and my assistant wasn't around.) Once all the the fiberglass tape was wetted out on both the hull and the deck I laid the fiberglass cloth into the cockpit area. The fiberglass cloth extends 50" from the permanent bulkhead and is wide enough to just cover the tape on the sides. I mixed up another batch of unthickened epoxy (15 pumps) and poured that into the middle of the sheet and then used a plastic scraper provided by CLC to spread the epoxy throughout the sheet. It took a little massaging to work out all the wrinkles, and the frayed edges kept wanting to pull away and were making a mess. I ended up trimming a lot of these frayed edges off and feather out what I didn't or couldn't trim. It took less than batches of epoxy to fully wet out the glass.


After all the glass was in place, I then sealed all the surfaces inside the boat with unthickened epoxy. It took about 2-1/2 15 pump batches to do this. Here is the final result.











Next step will be to come back and fill the weave on the fiberglass in the cockpit and to apply another coat of epoxy to all surfaces to ensure good sealing of the wood.  I'll probably do some light sanding as well on any surfaces that I might contact while paddling if they feel rough.  

I have a set of internal footbrace mounts on order from CLC.  The standard footbrace mounts are attached to the boat by drilling through the hull, so I opted for the slight cost of upgrading.  I can't move on to joining the hull to the deck until those are installed, so I have to fill that time.  Maybe I'll try my hand at carving a Greenland Paddle? 

Total time on this phase: 5.5 hrs. 
Total time on construction: 24.0 hours




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