Date: Mon, 12 Jul 1999 19:42:12 -0400
From: John Cooper <snopercod@CITCOM.NET>
Subject: Rib Construction
To: lancair.list@olsusa.com
Message-id: <3.0.5.32.19990712194212.0091bcf0@mail.citcom.net>
Mime-Version: 1.0

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I, too, made all my ribs and bulkheads out of foam that I laid up by hand
with a Thalco squeege. (The prepreg is porous and I didn't want my wing
ribs full of fuel. Besides, I am unconvinced that the finished product is
any lighter after all the tapes are applied.)

I laid up entire 2x4 sheets of clark foam one side at a time using the Burt
Rutan method: Squeege micro slurry into the foam then apply the appropriate
number and orientation of glass cloth plies and wet it out. Then squeege
the excess off. After that, I applied 4" strips of peel ply over the entire
surface to protect it until I needed a piece.

When the first side was set up, I trimmed the excess glass off on my table
saw, then flipped the foam over and did the second side the same way. (If
you use a table saw, make sure the peel-ply side is against the table, not
the foam side to prevent contamination due to any oil on the saw table.)  

Then when I needed a rib or bulkhead or seat back or center console piece
or whatever, I simply cut out what I needed with a jig saw or band saw.

Obviously, you want to do this procedure on a FLAT surface.

The only difficult part was keeping the excess epoxy from dripping down the
edge of the foam and wicking underneath making it impossible to bond to the
other side. Duct tape around the perimeter to prevent this from happening.

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