spars

[Kaz]

Just wondering what I should use to make my spars. Would 3/4" x 1 1/2" poplar be a good choice for a 5' wide teardrop. I plan on covering the roof with 2 layers of 1/8" baltic birch and 1 layer inside for a total of 17/8" roof thickness. I think 3 layers of ply laminated would add significant strength and it forms better than 1'4".

[kayakdlk]

I glued 2 1x2 pine boards together to make a 1 1/2 x 1 1/2 spar. I used glued together 1x2 oak boards for the hinge spar. I think you could get by with just a single 1x2 but by glue two boards together checking the grain I was hoping to prevent them from warping. I also liked the strength for a 5' wide and the extra width for the headliner glue bead. I only covered by roof with a single sheet of 1/8 Baltic Birch and then 7 oz cloth and epoxy. I used two layer 3/4 foam between roof ply and headliner and spray foam to fill any voids/gaps. I can sit on it and not worry about it caving in.

Dan

[noseoil]

Kaz, 1 layer of 1/8" top and bottom is generally plenty, depending on the skin you will be using to cover it. 3/4" × 1 1/2" is plenty for cross-members.

[KCStudly]

I have a combination of 1x2 cedar and poplar for most of my spars; 2x2 cedar for the spars and side pieces at the the vent fan frame (to give the fan flange full backing); and essentially two 1x2 red oak pieces glued together to form each of the hatch hinge spars (something hard for the hinge screws to bite into solidy).

All of this is over a 5mm thk ceiling ply and will be filled and covered by 1-1/2 inch foam, glued canvas, and paint.

One of two poplar spars has a bit of a dip in it, but the cedar ones are holding true.

Don't be surprised if a mod moves this thread to the Construction Tips & Techniques forum.