High density inserts

[boots]

Maybe some of you EPS shapers or owners of EPS boards can fill me in on this:

When is it necessary to  use high density inserts for fin boxes in EPS foam?
All the hand made epoxy paddle boards I've seen didn't look like they had foam inserts in the boxes, is it only needed in 1lb EPS blanks?

[K-541`]

Most eps surfboards don't need a fin box cassette beacause their is not a lot of load on the box unlike a sail board with all kinds of stress on it. I'am sure if you hit something hard with a SUB the box will rip out faster than you can blink. in that case I might build a cassette around the new box with 1/4 HD foam or try useing pour foam 2-part liquid by routing out a bigger hole around the damage and filling it up and then just rout into that foam and install the box. In 1lb I might think hard about it

[Dwight (DW)]

Most eps surfboards don't need a fin box cassette beacause their is not a lot of load on the box unlike a sail board with all kinds of stress on it. I'am sure if you hit something hard with a SUB the box will rip out faster than you can blink. in that case I might build a cassette around the new box with 1/4 HD foam or try useing pour foam 2-part liquid by routing out a bigger hole around the damage and filling it up and then just rout into that foam and install the box. In 1lb I might think hard about it

You don't have to hit anything to rip out a box real easy. Many years ago I saw a windsurfer dragging his board ashore, the board was positioned parallel to shore, fin tip stuck in sand, and wave caught the nose and rotated the board. Twisted the fin right out of the box. I'll never forget the shock of how harmless the wave looked that rotated his board on the beach and the ease with which his fin box was ripped out. Paddle boards are in the windsurfer class of monster boards with huge torque potential on the fin.

I can see inexperienced board owners having fin boxes popped in the same way. It would be wise for board builders to use high density cassettes on all construction types, or face the backlash when the masses start kooking out with these boards.