Estes Phoenix Bird Build Part 12 Primer Tips

At a launch, you'll see plenty of rounded over edges on square fins.

On the Phoenix Bird, only the leading edges of the fins are rounded.

TIP: To protect the squared outside edges of the fins from being sanded round, I set my finger over the edge (in the picture, over the outside edge) to act as a "bumper". It keeps the sandpaper from rolling over the square fin sides.

I've been using Duplicolor Primer Filler lately with good results.
I tend to spray just one heavier coat and sand that almost to surface instead of three or four thin coats.

The gray Duplicolor primer is thick and sands off in a powder.
I'll use 220 grit to remove the bulk of it then switch over to 400 grit to smooth that out.
You'll save some sandpaper as all fillers tend to load up.