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Old Feb 12, 2013, 04:10 PM
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AvB
Wind, hill, ... I'm keen ...
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Australia, QLD, Woody Point
Joined Nov 2006
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Mark, more a subject for the Scratcho thread or another composites thread, digressing from the PU theme! But a couple of quick comments/ replies:

1) Ampreg F230 and Sicomin PB250 in my experience so far are exactly the same - one is no better than the other. Fresh product is best. At least with Sicomin you can get small packs.

2) yes I like the idea of the expanding epoxy filled D-Box. Wings fly better if you keep them light behind the CG, so a good method is vacuum bonding pre-cut blue foam cores into the rear 3/4 of the chord (from TE forward). It allows you to cut slots for a socked spar and aileron stiffeners etc, which you do need for serious stiffness because the expanding epoxy is a bit plasticky. Fill the front empty section and the edges with the ExpEpoxy. One big tip is to make sure you use a thick bead it in areas where it is a thin join... it doesn't like to expand if it starts from a small layer.
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