When the refit began back in late 2007, one of the good things that led us to start the work was that there was very little deep corrosion in the aluminum hull and decks. But one of the worst areas for corrosion on the boat was under the mahogany toe rail. The original sealant had given up in some spots and let water wick into the wood. While starting rot in the wood, the water also worked its way to the fasteners that secured the toe rail to the aluminum deck. From there, water worked its way past the fasteners and under the original chromate primer, and that’s where the white aluminum oxide started to grow. We used a very different approach on the new mahogany toe rail than Chris Craft did originally, epoxying and bolting the toe rail to the deck, with painted fillets covering the joint. Water cannot come in from underneath like it did before. The DuPont MS1 clear coat I’m using on the toe rail will keep water from coming through the top and sides of the mahogany, so long as I keep up on the 5-year maintenance cycle. But I recently cut all of the holes and dry fitted the safety rail stanchions, and each of those holes can provide a path for water to start rotting the mahogany and ruining my new paint. To stop that from happening, I saturated each hole with epoxy.
I use the Vix Bit to center the drill in two stanchion screw holes. Then I temporarily secure the stanchion base with two wood screws. Then I drill the remaining holes with the Vix bit and step up through the drill sizes to 11/32, which is 1/32 larger than 5/16″, which is the size of the stanchion base oval head fasteners. I went slightly oversized because I’ll fill the holes with epoxy and I don’t want the screw threads cutting through the epoxy surface when I do the final installation. If water does somehow find its way into any of these screw holes, it will have a very hard time getting through the epoxy coating to the wood below.
The chrome shop apparently didn’t bother to remove the sealant from the under side of the stanchion bases before replating them. Fortunately, it doesn’t seem to have caused a problem for the new plating.
I should also mention that these holes I’m drilling for the fasteners only go as far as the aluminum deck. I won’t drill and tap the aluminum until I’m doing the final stanchion base installation. That way, the holes will hold epoxy like it’s in a cup, sealing the mahogany surface inside the hole as well as the aluminum that’s exposed by the drill point.
There are 20 stanchions, six cleats, and a few other bits and pieces that all needed to have the holes drilled out, and six steps for each hole. That’s a lot of tedious hole drilling. But eventually I got them all done and ready for epoxy.
Rather than wasting epoxy by filling each hole to the top, instead I filled each one 1/4 of the way or so then used one of the original bronze machine screws as a plunger to force the epoxy into the grain from the bottom of the hole to the top.
I use an acid brush to move the squeezed out epoxy into the bigger stanchion base hole to saturate it, too.
With each screw hole interior wetted out, I periodically returned to each stanchion and plunged the hole with the screw. This pushes the epoxy into the grain and keeps the surface wet all the way to the top. The screw threads also knock off any bubbles that form, which helps the epoxy wick in even better.
It took a day to do each side, first drilling all the holes. Then filling them with epoxy. Then going back and plunging with the screws 3-4 times, adding a bit of epoxy when the screws bottomed out, before the final plunge at each hole. That’s another weekend gone, but this was an essential step that will hopefully save me lots of maintenance and heartbreaking repairs in the future.