What is the technique in balsa sheeting foam core wings. I have read the manual recomending to use the Zap Finishing Resin or the Hobbypoxy Smooth n Easy Finishing Resin. Is these glues just regular epoxy? I have read at other places here on RCU that one could mix 50/50 white glue and water and use a brush to put it on the foam core. Also if I would like to lighten the struckture is it wise to remove some of the foam by cutting out holes on the foam core? What other ways is there to lighten? Changing the balsa sheets for lighter ones?