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I know this is an old thread,

PostPosted: Thu Apr 21, 2016 11:04 pm
by Brushy_Bill
On the subject of the spars.
Is there any reason I cannot saw
my spars from 3/4" plywood?

I am not talking about the ones
that support the hatch hinge, just
the others.

I was thinking they would be more stable
as far as warping goes until the skins
get applied.

Re: Does this look right?

PostPosted: Thu Apr 21, 2016 11:11 pm
by Graniterich
From my experience, plywood is not nearly as strong as 1x2 that cost less than a dollar for eight feet.

Re: Does this look right?

PostPosted: Fri Apr 22, 2016 6:41 am
by KCStudly
It has been done, but you have to think about how you are going to fasten them to the side walls and/or side wall ledges. Plywood doesn't like to have screws splitting the plies, so screwing into the ends or down thru an edge won't result in the strongest joint. True, glue does most of the work, and pocket screws can be used, but it is something to be aware of.

Re: Does this look right?

PostPosted: Fri Apr 22, 2016 6:58 am
by dales133
It would probably cost more for an inferior job fot the reasons given imho

Re: Does this look right?

PostPosted: Fri Apr 22, 2016 10:31 am
by Brushy_Bill
Thank you for the prompt replies, makes sense, splitting the plys wouldn't be a good thing.

Re: Does this look right?

PostPosted: Sun May 08, 2016 9:47 pm
by mjewell5
I never even considered using pine or plywood for the spars. I used Poplar for all of the spars, cabinetry, etc, because it is a hard wood and takes screws pretty well. Probably 5-10% heavier than pine, but I don't have to worry about knots and such causing weakness.

Also, I glued the interior and exterior skins, and used a brad nailer. Creates a nice monocoque unit, like an airplane wing, it's an incredibly strong structure.