I cleared my stick with Valspar Water Based exterior Spar Polyurethane. (got it at Home Depot)
It holds up well but will make the finish tacky if exhaust residue is left for a few hours. It'll dry up again in a day.

The flight box is oil based Polyurethane.... No problems at all with that stuff..

Polycryllic.. let to cure for 1 week.. 15% glow fuel took it right off in less than a minute.