I am looking to reduce the weight caused by the resin interfacing a foam core. The parts are vacuum bagged, not infused. The layup is typically 1-2 layers of ~5oz cloth, 3mm perforated divinycell H80, and then 1 layer of 3.7-5oz cloth on the inside. It can’t be bagged in one shot because the foam core will move around. The outer layer(s) get wet out on a table and transferred to the mold, then the foam core is coated with epoxy and placed on top. It is bagged until stiff, then the inner layer is bagged the next day. For the inner layer I am able to coat the foam with epoxy, lay the cloth in, and wet it out.
Part weights are reasonable but always looking to optimize. Is there a way to reduce weight? Some ideas are:
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Mix cabosil in the resin that gets spread out on the foam core. This should reduce the weight if it doesn’t interfere with resin traveling through the peel-ply.
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Pre-coat foam with cabosil/resin mix and allow to cure before using. You would almost need to vacuum bag it separate. I would use non perforated, and then perforate after cured. Probably more hassle than its worth.
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Sand the foam. It seems that 180 grit on a da leaves a much smoother surface with smaller pores to fill with resin.
I have done some 1’ square test panels with and without core and believe the resin to interface the foam core is ~1/4 the weight. I might do some test panels based on responses.