You should now prepare (xx) spars. These spars are dimensional lumber 1x2”. Actual measured dimensions are ¾”x 1 ½”. If you are not having any luck finding dimensional lumber that is straight, then buy some 1x4s or 1x6s and rip off a bunch of strips 1 ½” wide. Then cut them all to 58 ½” long. It helps to have a mechanical stop on your miter saw to ensure that all your spars are truly the same length.
The final spar, the one that the hurricane hinge will attach to should be cut from poplar. That’ll give the screws something to bite into!
You marked the locations of the spars in step 4. Now you are going to drill 3/16”” clearance holes for spars. Drill 2 holes per location from the inside. Then come back on the outside and countersink the holes.
Finally, using polyurethane glue, glue in all the spars, and put 2 screws in each end.
The headliner is made from 2 pieces of 4x5' x 1/8" plywood and 1 piece of 1x5'x1/8" plywood. The head liner pieces are joined together with a strips of plywood 4" wide x 5' long
The spar locations and headliner seam locations are noted in this drawing...
