Fitting forms to strongback

The plans state that each paper form should be exactly 10 inches from the next, starting at the bow and again at the stern, with the paper facing outward to the ends. I didn't use the recommended ½-inch thick MDF or plywood because I had a sheet of ¾-inch MDF. That threw off all the plan spacing, and I had to recalculate the spacing and the new distance at the centre where the two outward-facing papers now have a ¾-inch form on the inside.

Strongback and form with bow section

Having determined the spacing, I set about making U-shaped spacers to fit between the forms and over the aluminium strongback. Looking in my timber stack, I found a particle board sheet and cut it into strips: one for the bottom (top of the U) and two side strips. I then routed two grooves into the bottom and glued the two sides in at right angles. But first, I had to cut all strips to exactly the correct dimension for the space between the forms, not 9½ inches.

Cutting U spacers

I used the U-shape to get exactly the correct spacing between the paper forms, to get them at right angles to the strongback, and of course, to keep them parallel. The middle U is clever in that it has two wedges in it to force the forms apart towards the bow and stern.

U spacer

Having slid the forms on in the correct order and placed the U's in place, I then focused on the bow and stern end pieces. These are at right angles to the forms and are inserted into the ends of the strongback. At the very end of the bow is a piece of wood that forms a triangle onto which the actual strips are glued. The outline is given in the plan, but one has to work out where the narrowing starts and exactly where the sharp point is in the middle of the kayak.  The strips attach to this internal end piece.  An additional external bow and stern piece is then added when the kayak is almost finished and glued together.

Calculating the shape of inner bow section

Again, the thickness of my form wood complicated the calculations. I took a lovely piece of myrtle and put it through the thicknesser to get just the right thickness. Then I started to plane the end to a point, following the curve of the bow dimensions. This isn't glued to the bow or stern form but taped in place for when one comes to remove the forms from the finished kayak halves.

Inner bow section in place with tape

All set to slide the forms onto the strongback, but I hadn't finished shaping the forms into their final form, which required the bandsaw to cut the exact shape. Having cut three forms and sanded them to fit the curvature of the hull from the bow and to the exact outline of the plan, I started the fourth.

I started the bandsaw and placed the form to begin cutting. I was about 30 cm into the cut when BANG! The bandsaw blade broke. No worries, I had a spare, but it turned out to be so blunt that the wood started to smoke. Getting a replacement blade on the Friday of the Australia Day long weekend for a Delta 28-140, which is 45 years old, is a challenge for which I have no solution.

The next post will explain what I did in the interim.