I treat it like the Elmers wood filler. Thin it slightly so it is thick syrup/thin PB. Use a laquer thinner. Then brush it on with cheap bristle paint brush (1/2" - 1"). Do about about 1-2 ft of spiral at a time. Let it be a little thick. Then imediately follow with a new safety razor as a "puddy Knife", holding it about 90 degrees to the tube and axially in line with the tube. Clean off buildup on the blade as it gets thick. Sanding is easy. On bigger BTs, I use a 1/4 sheet vibrating sander.