I used to use sealer (BLO) Boiled Linseed Oil, but found that if you sand your lures really well I didn't need a sealer. I sand my lures while they are still on the lathe so they get really smooth. I also use eastern red cedar for the wood type. After I've predrilled all holes needed, then I'll dip in a primer, I use white, sometimes I may dip it twice (depends on how grainy the wood is) but the eastern red cedar is usually very smooth after sanding. After primer is dry then I airbrush. Etex is the last step for me and I guess I must be lucky or something, but other than the bubbles, I've had no problems with Etex. I have posted this before, but I use denatured alcohol to clean the painted lures and allow to dry. Then apply the Etex with a cheapo bristle brush from HF. Put on the spinner with a light bulb or sometimes two bulbs in place. For the first 4-5 minutes on the spinner I blow air from a heat gun on the lowest setting on the lures, then let them spin until dry(usually overnight). Sometimes the lures may take 24 hours to cure. I did do an oak lure once and found that it should have been sealed because the wood was so grainy.
Benji