sensei

I have spent almost 47 years in the aerospace composites industry, and I will tell you right now using epoxy resins for finishing purposes in the name of strength is a wast of time. It doesn’t add any more strength to the outside of a model than urethane, but in many cases especially by the new guys, it will come out heavier. Strength and rash proofing comes from multiple plies of glass and epoxy resin. Unfortunately for finishing purposes a single ply of 3/4 glass cloth is the suggested norm over balsa and plywood in an effort to keep the grain in the woods from showing through and to keep it light at the same time, so that single ply doesn’t help with hanger rash and doesn’t do a thing worth mentioning over epoxy VS urethane. I personally use Minwax oil based urethane, and have so for decades, unless of course I am building an all composite airframe or parts. Water based can in fact swell and or warp thin balsa wood so I don’t use it.

Bob