This might be a good thing for making weed fins?

Years ago, Tom Chalko experimented with adding carbide powder to the outside leading edge of some of Mal Wrights Time Machine Moulded Carbon fins. It seemed to make a big difference if we ran it though the sand at Sandy Point.

Most weed fins these days are CNC out of G10 plate. But I wonder if using this sort of resin to make compressed plates for CNC would destroy the CNC cutting tips even faster?!

I have used very fine (1200 grit) silicone carbide (from a Lapidary supplier) as a starter coat when making fins.

Works a treat, Albany weed doesn't touch it, you can run them through gravel without any damage.

The issue is demoulding, it's that good, it'll f'k up files, sand paper, wetndry, so extra care is needed with the layups.

Have though previously of using "tooling" epoxy gel coat, very abrasion resistant, but you can only get it in a big can.

cheaper - aluminium powder in resin.

That's what most tooling coats are.

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elmo said..
I have used very fine (1200 grit) silicone carbide (from a Lapidary supplier) as a starter coat when making fins.

Works a treat, Albany weed doesn't touch it, you can run them through gravel without any damage.

The issue is demoulding, it's that good, it'll f'k up files, sand paper, wetndry, so extra care is needed with the layups.

Have though previously of using "tooling" epoxy gel coat, very abrasion resistant, but you can only get it in a big can.

Ahh, very interesting Elmo. Also that observation about tooling Epoxy Gelcoat. I have made many moulds with polyester tooling Gelcoat, but had not come across Epoxy Tooling Gelcoat.

Yes, I remember it was impossible to 'sand' those TM fins if you needed to refinish the leading edge. Fortunately, the fins came out of the moulds very well.

I have always discounted using Carbon Weed Fins because carbon erodes very easily, but moulding using these materials, it might be a very workable option.

Have also tried Aluminium powder with mixed results.

Worst one was graphite which they recommended for the bottom s of kayaks. Was next to useless and got filthy sanding it.

there are wear resistant epoxies which my customers use on slurry pumps, again pot sizes are generally on an industrial scale and I don't know how you'd go bonding to it after

Looks interesting, thanks for the link.
My usual is .....
Gel coat (fin molding)
mix 100mls resin with +50% calcite, 25% graphite, 25% aluminium oxide
I get calcite from Pottery suppliers (used for glaze process)
Gives a quite hard surface but I wonder if it's hard enough for Oz weed?

Something else to consider are post machining modifications such as ion implantation. These can be done in a low vacuum at ~100C and you can target the modification to where it is required (eg. leading edge of fin). The ion bombardment does not create a coating, the ions are implanted in the top few microns without dimensional change.
It's a common technique for medical devices for friction and hardness modification.

www.bodycote.com/services/heat-treatment/ion-implantation/