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Old January 24th 08, 01:00 PM posted to rec.aviation.homebuilt
Stealth Pilot[_2_]
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Default Wood Laminations and Springback

On Wed, 23 Jan 2008 19:31:29 -0500, "Kyle Boatright"
wrote:

I'm working on the center section for a Hatz. The trailing edge of the
center section is a recurved lamination that provides better access to the
front cockpit.

I've steamed and clamped the strips into a form, and they have taken on some
of the curve, but when I unclamp 'em after they dry, I get significant
springback. The question is whether I need to allow for this in the
finished lamination, or whether the springback will go away when I glue up
the assembly?

FYI, the lamination starts as four 3" x 1/4" strips.

Thanks in advance,

Kyle Boatright


Kyle
wood is cellulose which is actually massive sugar molecules joined end
to end. joining all the cellulose together are a family of molecules
known as lignins. some lignins are thermo plastic and some are
thermosetting.
when you select wood for steaming and laminating you need to select a
timber with thermo softening lignins or you'll never get it to go soft
enough for forming.
when you've steamed a wood and placed it hot on the former then
clamped it in place until cold the wood should come off the former
with no springback. ...if it is a thermosoftening lignin.

I'd say that you've picked the wrong timber for laminating.
Stealth Pilot