Question: Should I fuel proof my fuselage?

Answer: Well, it depends on if your firewall is removeable.

If your firewall is not removeable, we do not recommend trying to fuel proof the fuel tank compartment. The only way fuel can get into the fuel tank compartment in this type of model is via a leaking tank or leaking tank to firewall gasket. You've generally be better off putting the time into carefully assembling the tank (do not overtighten the stopper cinch bolt) than trying to fuel proof the fuel tank compartment. Sort of a prevent leaks rather than plan for them approach.

If your firewall is removeable then it's a bit more of a six of one, a half dozen of the other type of decision. It's not really necessary but if you've got the time and material it probably won't hurt. Fuel proofing will be adding weight to the model so don't go overboard and really ladel the sealant on.

Here is some information on sealing the removeable power module firewall itself that is worth reviewing vis-a-vis considering a similar approach to fuel proofing the fuel tank compartment.

Question: Can I finish my firewall to enhance it's appearance and seal it against oil and fuel?

Answer: Yes.

Better Answer: The firewalls are made from either 6mm plywood or multiple layers of thinner 2-3mm plywood laminated together. They are more than strong enough for any modelling application. They will withstand oil and fuel without further treatment or finishing. If you wish to seal the edges and faces that is also fine. When finishing, we suggest checking the edges for any voids, fill them with CA or Epoxy and then seal the edges and faces with finishing resin or epoxy. Let dry and then install your engine mounts and tank.

Question: My VMAR model came with a long aileron running along almost the entire trailing edge of the wing panel. My model also came equipped with four servo mounting bays and instructions for the optional cutting of each single aileron into a flap and aileron or flap and flaperon. I have cut each single aileron as instructed. Should I seal the exposed wood ends of each of the resulting control surfaces? What should I use for sealant that will stand up to fuels and oils?

Answer: Yes you should seal the exposed wood ends so that they are fuel proof. You can use ZAP-CA as a quick sealant. Just apply a small amount at a time and let it wick into the wood. A better solution would be Pacer Finishing Resin which is a thin two part system that you mix together in equal amounts and then brush on.