Fuel fittings shouldn't need any type of sealant, they all are metal to metal crush type 45 degree seals. If they are tight enough they seal....Otherwise on hose to line connections double up the hose clamps if you want to be extra safe.
Like he sez...no sealant. Its a metal-to-metal situation. You maybe able to glue together low pressure liquid or gaseous connections and prevent a leak, Try that with 3,000psi aircraft hydraulic systems? or, even your wife's gas clothes dryer...read the install instruction...NO sealer/glue/compound/etc. on the flare fitting.
