Monday, January 01, 2007

Planking with structual foam - take two

Happy new year!
Now back to work.
My goal was to get the port side outer half planked and ready for laminating over my Christmas break from work at the office. I shall certainly achieve this goal. Work has proceeded much faster and my workmanship has improved from the first float half construction.

In the picture above you can see some of the elements of my current best technique.

  1. First I cut enough panels to the correct width and keep them handy. I am cutting them to 7 inch widths and use a table saw and guides to get a decent edge quality. The form frames on the deck side provide a handy storage location.
  2. Then I fit the individual panels. I use a tape measure to get the coarse length and cut the panel square. With the panel held in the frames and butted up against the deck flange I mark with pencil the width angle required and cut. I then carefully carve the edge on the keel side to the angle required to meet flush with the keel strip. This sequence repeats until you have enough fitted strips that can be glued in a work session.

  1. In a glueing session the strip edges are coated with the adhesive and then clamped together by using screws through the form frame battens from below. The screws I use are number #8 1-1/4 inch length applied with a washer to grab the maximum amount of foam without poking through the top surface of the foam. I am using a waterproof polyurethane construction adhesive that is relatively easy to apply and work with. The excess glue that is squeezed out onto the top surface I immediately clean off using a Popsicle stick. The adhesive does foam a bit during the curing process leaving a small high point. This cuts off readily with the sharp utility knife when fully cured. I do not try to clean up underneath. I have found that the excess adhesive, with the aid of gravity, does not smear and is easily cut off when the float is removed from the form frames.
I am not tracking hours on this project but this float half took me two foam fitting sessions and two gluing sessions. A session for me could never extend over 4 or 5 hours with the required dog walks and shopping with the family.

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