Epoxy SUP Fin Box Replacement
The following explains the steps in replacing a fin box on an epoxy SUP.
1) Scribe a rectangle around the damaged area with a sharpie pen. Use a Dremel tool to cut along scribed line through the epoxy skin layer and slightly into the eps foam. After removing the epoxy layer use pliers and a chisel to remove the damaged plastic fin box.
2) Clean out and level the excavation using a small chisel to prepare an even base for the replacement fin box. The wood stringer takes a little extra effort.
3) Center the replacement fin box and check that it is level. The bottoms of the 4 tabs should be level with the adjacent undamaged areas. The portion of the fin box above the tabs is elevated above the final surface of the board and later must be removed with a chisel (see step 6).
4) Tape securely over the fin box to prevent entry of liquid epoxy resin. Do a final check of level (N-S & E-W). Fill void surrounding fin box with slow cure epoxy resin.
5) Gently place a cutout of fiberglass cloth on top of freshly poured resin surrounding the repaired area.
6) Saturate fiberglass cloth with resin. Keep overfill minimal to reduce sanding time. After resin has hardened, use a sharp chisel to remove elevated portion of fin box.
6) Sand chiseled fin box and repaired areas smooth. Start with 60 grit, then follow with 100 grit and finish with 220 grit. Install fin! For colored boards a painting step would follow.