The waste pumpout deck plate, installed and ready for the hose |
It had been a long time since I had drilled the hole through the deck. In the interim, I had covered the hole with duct tape. The boat itself, of course, was tented. Now I needed to route out the balsa core around the perimeter of the hole and fill the routed-out perimeter with thickened epoxy.
For this task I called upon my Dremel.
I used a 115 bit. The cutting head of this bit is 3/8 inch, which is the exact thickness of the balsa core.
I had learned this technique from Maine Sail on his Compass Marine website. See the link on the homepage of this blog.
The benefit of this technique as opposed to others out there is that it is fast and accurate, especially once you get the hang of it.
After I had routed out the balsa core, I inserted the deck plate and drilled the three holes necessary for mounting it to the deck.
I drilled the holes to 3/16 inch to accommodate the #10 screws. Then I over-drilled the holes to 5/16 inch, but only in the top layer of fiberglass, not the second layer that's on the bottom of the balsa core. This enabled me to insert the 5/16 inch Dremel bit and route out the balsa core in these holes.
Before I mixed up the RAKA 127 resin and 350 non-blush hardener, I opened up a new roll of Gorilla brand duct tape. This is top-of-the-line duct tape, not the cheap stuff that tears easily and doesn't stick worth a flip.
This tape would prevent the neat epoxy from dripping down into the head.
The picture below gives you a good indication of the gap that I needed to fill with the thickened epoxy after I had wet it out with the neat.
If you tape a hole with Gorilla tape, then you can almost be guaranteed that the neat epoxy will not find a way to drip out of it.
I did this work around the same time that I filled most of the other holes in the deck. The blue painter's tape protected the gelcoat from drips of epoxy on the deck.
As I recall, I filled some 80 holes in the deck at this time, and those weren't all the holes. I did another, yet smaller set of them afterward.
I allowed the epoxy to cure, and then I cleaned up the excess with the Dremel, this time with a 50 grit sanding drum attached. I also put a slight bevel along the perimeter of the hole so that the butyl tape would more easily form a gasket of sorts when I installed the deck plate.
I also drilled out the screw holes with a 3/16 inch bit. Then I beveled each hole with a countersink bit. This of course would help to create a gasket of sorts around each screw.
I cleaned up the holes with acetone, and then I cleaned the deck plate itself. Afterward, I wrapped butyl tape around the flange.
I also wrapped the heads of the screws.
When I installed the deck plate, a friend stood on deck with a screwdriver. Down below, I turned the nuts with a wrench.
As we tightened down the hardware, the butyl tape slowly squeezed out along the perimeter of the flange.
Now I could install the hose for this deck plate and all the other hoses for that matter.
This ends this brief posting on the work I did to install the deck plate for the holding tank pumpout hose on Oystercatcher, my Ericson 25.
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