Tuesday, January 23, 2007

Global Warming, and other Sticky subjects

Up until about a week ago, the weather here in New Hampshire was doing its part to lend additional credibility to Al Gore and everyone else proclaiming that we are in the midst of a Global Warming crisis. Not that I was a skeptic, nor an absolute 'believer', I will leave the debate for other forums. However, it is hard to argue when the thermometer indicates nearly 70° on January 6 in New Hampshire. This is by no means an official reckoning, nor do I know if it was the highest temperature here that week. I just know that I enjoyed being able to open my shop doors and still be comfortable.

Since I have lived in the northeastern United States for most of my life, I was relatively confident that the unusually warm weather was only temporary, and I decided to make the most of it with regard to my boat building project. Yes, it was time to make some Goo.

I chose the System Three line of epoxy products. Now, I realize that they offer some 'application specific' products for boat construction, but I decided to go ahead and try it the old fashioned way. Yep, I mixed up batches of my own epoxy goo for the fillets that hold the hull together once the copper wires are removed. Before I get too far ahead of myself in this saga, I need to back up a little here. It's important to ensure that the boat has the correct shape, so that it will track well, and not pull to one side or the other and require constant corrections. This could pose a challenge regardless if you are manning the tiller or a pair of oars.

After getting the hull all stitched together, I made sure that the saw horses were level from side-to-side. Next, I used a long clamping guide to bring the beam (the widest part of the boat) to 50". Then I laid out three levels to see where some fine tuning was required.  In order to make sure that I had the correct shape where the front bulkhead would go, I cut out a temporary bulkhead and then cut off the bottom half and wired it in place. This allowed me to easily form the fillets under it without breaks or interruption.

Since there was a slight amount of twist to the hull, I firmly twisted the bow end in the opposite direction while my son held the stern end. This resulted in the sides being very nearly level from side-to-side, but being somewhat obsessive, I was not satisfied yet. Then I found that when I hung some clamps on the high side, it was pretty close to perfect.

The fillets (pronounced "fill its"), are made by mixing the epoxy with wood flour (fine saw dust). Then this sticky mix is spread and formed along the seams where the sides meet the bottom, around the stern, and inside the stem. Once the fillets are formed, then two layers of 4" wide fiberglass tape are wetted out on top of the fillets. I spread and rolled a coat of unthickened epoxy all around the interior of the hull to seal the wood. I left the clamps in place for 24 hours to hold the shape until the epoxy cured.

Next, we go bottoms up and do a disappearing act. Stay tuned!

Tuesday, January 16, 2007

A Stitch in Time

I've been having so much fun working on the boat that I have gotten behind in posting updates to this blog. I really have not kept track of time spent on the project. I thought about it, and decided not to. I have found that I enjoy the process much more when time becomes unimportant. I do have the date stamps from the digital photo files which seem to keep track of my progress in the stream of time, without the need for me to think about the elapsed or cumulative time expended. Now that I've expounded on my philosophy of the relationship between time and a recreational project, I'll move on to the 'Stitching'...

After I got the majority of the boat parts cut out and trimmed to the 'final' shape and dimensions, I was eager to see what it would look like in 3D. Plus, I rationalized my eagerness with the theory that it would be good to make sure that things would indeed fit together correctly before I started the 'stitching and gluing'. So I proceeded to prop the parts together, and sure enough, it began to look like a boat. Prior to drilling the holes for the stitch wire, I planed a small bevel along the edges of the bottom and side panels. This helps in getting the panels to align and stay without slipping apart as much.

The stitching process starts with drilling 3/32 inch holes, every six inches along the perimeter of the sides, bottom, and transom. I used a six inch machinist's rule to mark these off, about 1/2 inch in from the edge.   I started with the bottom panel, drilling the holes all around. Then before drilling the sides and transom, I propped these in place again, with the bottom panel allowed to 'sag' across the saw horses, and marked for the holes to line up with the ones already drilled in the bottom. This is to account for the curves.   If you simply measure and drill the sides every six inches, the holes would not line up with the ones in the bottom. I also spaced the holes at about three inches on the stem (front of the bow where the two sides come together). Then I cut the 18 gauge bare copper wire in lengths of about three or four inches. I found the 50' rolls of wire at Home Depot in the hardware section for hanging pictures.

The assembly sequence I followed was to start with one side at the stern end, inserting wire and loosly twisting, working my way forward.   After the hull parts are held in place, it's time to go back around and tighten the wires with a few additional twists. Now it's really beginning to look like a boat and the onlookers are impressed :)