FCS Plugs

As far as I can tell, an FCS plug is quite similar to a leash plug. So why do you need to use an H tool to drill all the way to the deck on a FCS plug, but not vice versa with a leash plug.

Someone told me that FCS plugs come under far more stress than leash plugs, but I think this is a load of baloney. The next time you get caught inside by a solid 6 foot+ wave, try telling me that your leash plug doesn’t go through just as much stress as an FCS plug.

Some of you might be thinking an deck plug gets more strength being placed on the stringer, but I’ve had plenty of boards that have a leash plug “off centre”.

Also has anyone tried using “Cabosil” when resining in their FCS plugs?

the difference is a concept of “shear strenght” vs “torsion” caused by the moments created…

if you dont understand that think of this example; whats harder to bend? a nail all the way inside a piece of wood with a string attached to the head or a longer nail with a portion out of the wood and the string attached to the head? The answer should be obvious.

Thankyou for clearing that up, the difference now makes a lot more sense. Cheers.


Cabosil is Calcium Carbonate a bulk filling agent.

I have experimented using different grades of Cabosil in FCS installations.

I found that it doesnt help in any beneficial manner.

Basically its filler and in high addition rates will degrade any mechanical properties you may have conjured by the addition of long strand milled fibres etc.

Some believe the addition of Cabosil will effectively remove some of the heat from the resin exotherm.

But i have found that bonding properties of resin to plug is affected significantly.

FCS does not recommend the addition of Cabosil.

i seriously recommend using milled fibre

Yes its about torque at the plug. The H adds torsional flex resistance to the plug by anchoring its base to the deck. This anchoring is not very robust and thus optional. You can accomplish the same without the H…after making the hole, simply take needle nose pliers or screwdriver and dig out a little hole in the foam to the deck lam. The center plugs install can be strengthened by taking out a little foam on either side of the stringer.

If you want a real strong FCS plug install, take out some of the foam along the plug hole’s upper edge, underneath the bottom lam creating a resin fillet that improves the bond with the bottom lam…its like the flare at the base of most tree trunks.