eps foam/ epoxy resin fins...

General Discussion
1

… has anyone here made some of these ?

How did they go ?

I’ve come across some of this foam, and want to have a go at making some F.C.S. fins, and also finbox single fins from it .

    ben
2

Lotta work, very little gain, unless your fins are 15" long or longer.

Box fins, almost not worth the tech problems of base and fin durability.

GlassOns better, but no real gain for surfboard sized fins.

Less durable for bottom abuse from grounding, but you can tune the flex some.

3

"…HAVE you made any ?

… how did they go ? "

ben

"…15 " long fins " !!! what the… !

4

I’ve done epoxy/glass lay-ups, I suppose there is going to be some glass or some kinda cloth in there somewheres, eh?

I fall into a sorta “stiff as can be, but otherwise thin as can be” fin philosophy, so I am avoiding all sorts of foam fillers. The epoxy is not tough to work with relative to polyester - actually - it was kinda six of one half dozen the other.

5

thanks for that blakestah… [yes, I WILL be using fibreglass cloth , too !]

     ben
6

I’ve done a bunch of these for paddleboards. All glass-ons though. 6 layers of 6 oz per side with an EPS core. Still pretty flexy. Not too big of an issue on paddleboards, but could be on surfboards. Be careful using epoxy installing FCS plugs. I once had the tail of my board literaly start smoking putting these in with epoxy in a tropical climate. AHHH!!! I was running upstairs and getting ice out of the freezer to pile on. Last I heard that board is still going though.

7

thanks Jong…the fins are for an existing [ie: already plugged !] board.

    ben
8

This is yet to be glassed. It gets 2 layers of 6 oz cloth on each side. It’s not eps and epoxy, it’s a two part urathane (4 lb) and polyester resin. I use the thickness of the fiberglass core (on this fin it is 18 layers of 6 oz) to control most of the flex. I find foiling the foam is much easier then foiling plywood.