For you wood finishing experts.

I put together a furled leader jig based on the instructions that came with Kathy Scott dvd. To finish it off I decided to put a few coates of varnish (Man O War) on it. I am about to apply a third coat. Between each dried coat I rub with 00 grade steelwool and remove the remaining small dust particles with a tack rag. My second coat has a lot of bubbles in it. I gently stir the varnish with a wide piece of wood and then wait 15 minutes before applying the varish. The varnish is applied with a quality paint brush starting at the center and working out in long smooth strokes. Any suggestions why I am getting bubbles in the finish?