The proper method of making a light A-Sandwich (skins with a core) are as follows:

1. Lay the skins up first, you need to pull as much vacumm as you can to consolodate the lay-up. Aim for a 38% resin to weight factor and do not let the lay up bleed, completely seal the lay-up with a top caul plate and teflon tape (or clear tape) around the edges, then poke a hole with a pin in the tape every 6 inches. (to burp the lay-up when vacuum is applied) Then envelope bag your lay-up and pull 26.4 ~27.2 inches of vacuum.

2. Bake your balsa for 3 hrs at 200°F to drive off any moisture.
(moisture is the # 1 reason for laminate failures)

3. Once the skins are fully cured, skuff up the bonding side of the skin with a sand blaster or 100 to 180 grit sand paper. REMOVE ALL GLOSS!!!!!

4. Mix up a thick slurry of micro balloons and epoxy. Spread a thin layer (15 thousands) of this slurry on to the bonding side of the skins, then install your core material and pull approperate vacuum to not crush the core.


This method will produce a low weight, high strength, mil spec part every time.

Regards,