Re: drill-fill-drill

Posted by LeeG on Aug 27, 2007

Drill, fill, drill is appropriate for through bolt applications where the hardware screw/bolt is a constant diameter going through a soft absorbant core. Think of bolts/machine screws going through a balsa core deck on a sailboat to hold cleats or winches. It's different than simply sealing a hole in absorbant wood.

For tapered #10 wood screws going through a hard fiberglass deck skin, 4mm ply and THEN into relatively soft cypress sheerclamp it's kind of a mistaken application. Drill,fill, drill would make sense if you used a fullers bit but it's kind of unnecessary,,and messy for the fullers bit.

My $.02 is that it's worth sealing/hardening the holes with epoxy but you don't have to go overbooard. Put down a piece of blue masking tape, drill the hole, screw in/out to set the threads in the sheerclamp and diameter of the shank through the deck, inject some epoxy with a syringe, wipe off excess, it'll soak down through the soft end grain and cypress, when 3/4 cured install screw with a LITTLE dab of silicone on threads. The epoxy will be soft enough to allow the screw to set and cure around the coated threads.

My experience with deck rigging using #10brz screws was re-rigging the original CLC demo boats and finding a few of the screws in every boat stripped out so that re-rigging required d/f/d. The problem with using JUST silicone is that the tapered screw is going into a constant diameter hole through different density material. The wood screw is being pulled down through a hard epoxied deck by threads in relatively soft cypress. When you lubricate the screw with silicone it's easy to exceed the grip of the threads in the softer cypress as the friction in the shank obscures the friction in the threads that tells you you're a half turn from stripping the wood.

It's not a big deal but it's bothersome to screw in the strap that holds down a hatch and have the screw strip out.

Part of the reason that the sheerclamps are as big as they are is simply to make it possible to use the 3/4" ring nails and 1" brz hardware screws. If you cut the sheerclamp dimensions down you can remove a pound of weight and mount the deck hardware straight through the 4mm deck.

In Response to: Re: drill-fill-drill on d by ChrisMak on Aug 27, 2007