In this video we'll show you how to install a standard longboard fin box into a longboard surfboard or SUP using a method that involves putting down a fiberglass patch under the box.

The basic process is to:

Route a hole in the board that is about 1/16" wider on each side than the box and 1/16" deeper.

Mask off around hole and cut glass patch that will stick up past the edge of the hole with the box in it.

Mix up resin with white pigment (or whatever color you desire)

Pour about 1/4" layer of resin into hole, place fiberglass patch under box and press the box into place. Verify that there is enough resin and add as needed, remove excess.

After resin cures grind box flush with board. After sanding install fin.

Materials and tools used in this video:
Fin box Jig
Porter Cable Plunge Router
1/2" 2 flute router bit (recommend 1.25" cutting edge bit)
10.5" Fin Box
3M 233+ tape 1.5" width
Epoxy resin with SLOW hardener (this was an install into EPS foam)
White Pigment
6oz 7533 fiberglass fabric
7" grinder with 80 grit disc (recommend 50 or 60 grit)
Festool 6" sander with 80 grit paper
Utility Knife