Tuesday, January 18, 2011

All Hands on Deck

The next task in the deck planking was to fit and epoxy down all the longitudinal planks. Beginning at the center king plank, I worked my way outward fitting and "clamping" each board in place using 3/16" fender washers with #8 round head sheet metal screws 3/4" long. I used the grid lines already on the subdeck to establish hold downs every 4" along each plank. A pilot hole was drilled prior to putting in a screw. Where the leading edge of a plank mated to the perimeter cover boards, a rough angle cut was made on the chop saw or band saw. Then holding the plank in place, a final line was marked using a spacer. I sanded to the line on my 1" stationary belt sander. (Actual work took a lot longer than writing about it.)

A box of 100 washers allowed me to get two or three rows done on each side of the boat at a time. I used pieces of luan plywood as spacers which happen to measure 3/16" thick. Once I had a batch ready to go, all screws were removed and the unthickened epoxy spread on the subdeck areas to be glued and the underneath side of each plank. Then thickened epoxy was spread on each plank and the plank put in place. The washer/screws were hand started and then beginning at the forward end, spacers put in place and the screws tightened to lock the plank in place.

After a set of planks were fit and screws tightened, the spacers were removed so they wouldn't get bonded in place. I put in some 3/16" tile spacers just to make sure nothing moved, but they were not necessary. After the epoxy set overnight, the screws and washers were removed. Any washer that stuck to the wood was unstuck with a chisel. I put the rounded edge of the spacer towards the wood to reduce the chance of marking the wood and helping with removal if stuck.

The process was tedious and my shoulder hurt at times from holding the cordless screwdriver, but seeing the deck transform from boring to way cool was worth all the fuss. It took four days of work but I'm ready to move on to the next step if I can figure out what that is. On the last day of epoxy work I made some sample boards with planking scraps so I can experiment with staining, finishing, and gap filling.

However, I have a few more screws to remove first.

Tuesday, January 4, 2011

Stacking the Deck

The first step in the deck planking process was laying out the lines on the subdeck plywood so I could figure out what wood I needed to do the job. I drew in a 2" grid pattern on the sub-deck to ensure that the center planking would be symetrical. Using a batten, I drew in the perimeter cover board lines to follow the carlings aft of the dash and stay a "constant distance off the shear line" forward of the dash. I made the first line drawn on the forward deck (that I liked) the "master" and copied it to the other side. There is a slight difference in distance to the shear line from one side to the other, but not enough to worry about.

Then a trip to Armstong millworks to buy some African Mohoghany for the deck planking and then learn how to re-saw. The guys at Armstrong suggested that starting with 4/4 stock planed to as thick as possible (about .90") would be the best approach.

I started with laying out the boards along one side of the boat to determine joint locations to get a 12' long 10" wide board to cover the width and length. Due to the limitations of my shop, the board was cut into the pieces and angles necessary to go around the boat on one side, then each piece re-sawn to create the piece for the opposite side. With a riser kit previously installed on my bandsaw, a new 1/2" wide skip tooth blade, new Olsen "cool blocks" and a 6" tall fence, I started bandsawing the wood for the outer perimeter planking. The piece at the back of the boat was 9 3/4" wide and the re-saw went very, very, slowly, but it worked. Then a few trips through the thickness planer (new blades installed) yielded planks about .34" thick. Using countersunk screws, the first piece was located, beginning at the aft end of the boat and working forward, a joint line established, chop cut on the mitre saw, reinstalled and the next piece cut to fit up against the previous piece.
After the joints were established, the inside line location was transferred from the sub-deck to the underside of the cover boards. In the cockpit and motor opening area, tracing on the underside was straightforward. In other areas the grid pattern was used to re-create the line by tracing the inside edge of the boards onto the grid pattern and measuring to the line intersection at each grid line. Tedious, but it worked. Line was cut on the bandsaw about 1/32" proud and then sanded to the line with a small 1" stationary belt sander. Outer lines were traced, cut, and sanded in a similar manner.

The kingplank down the middle of the boat took a bit of trial and error to find a width that looked "right". I started at 6 1/2" wide, about an inch wider than the perimeter boards in the fore deck area and it seemed too dominant. At 5 1/2" it still seemed too wide, so eventually my aesthetic director concurred with a 4" wide being the "right" width.

The grid pattern helped with cyphering out the width of the longitudinal planks. Eventually settling on 1 7/8" width, and a 3/16" gap. In order to fully utilize the boards I had purchased and not have to go buy more wood, I needed to squeeze four planks from a board width of just under 7 3/4" inch. (Maybe the king plank should have been a bit wider!) This created an opportunity to buy a new tool for the shop - a micro-kerf table saw blade which only cuts a 1/16" wide kerf. After creating a new table saw zero-clearance insert with a splitter, I was all set to cut the planks. The new blade cut like butter and I got all the pieces needed to cover the deck.

The plan at the moment is to stain the perimeter and king planks a darker color to provide greater contrast. Then finish all the planks to seal all the grain and complete the deck using a white pigmented epoxy to fill the gaps.