BMS School Rocket, Build, Part 7, Filling The Fin Grain

Here's one side of one fin with the filler brushed on.

Notice I didn't brush filler onto the TTW fin tab.

Many builders comment on forums about how CWF filler warps their  fins.

With the filler on just one side of the fin, the fin will warp as it dries.

Don't worry, the fin will flatten out when CWF is brushed on the other side and allowed to dry.