It might be better to coat the entire hatch with epoxy (instead of just the edges).
At the boat shop, we epoxy coat the wood parts and then coat them with 3 coats of Pettit Z-spar Flagship varnish.
The parts seem to hold up for 2-3 years or so before they need recoated. Usually we can just sand them down and re-varnish.
The curved knee brace seems to hold up the longest, while parts that flex (like the gunnels) and the horizontal surfaces need recoating sooner.
Sharp edges fails sooner than eased edges.
On my Vega, I made a block to mount a foredeck light on the mast. I made it out of Brazilian Cherry (just because I had some laying around, not because it is especially well suited for this).
I did a thinned coating of epoxy and then a thicker coat on all sides followed by 2 coats of an automotive clear coat. It still looked great 3 years later.
At the same time, I did a test block where I did not epoxy coat the backside, but did clear coat it. I then set it one a rock in my yard. After about a year the epoxy lifted off the end grain.
Sealing all sides seems to be crucial for longevity.
The clear coat seems to work well for parts that don\'t get wear, but I like varnish better for the ease of touch up.
There is some 2K (two component) coating that is made in Germany, the name starts with a "C" and it is supposed to be quite good. It remains more flexible than typical 2K clearcoats (ie awlgrip or system 3, or automotive)
I may give that a try, as the biggest problem I see with automotive clear coats is that they are too brittle and don\'t move enough with the wood.
I need to make new hatches for my boat as well.
That is a great idea to make them a caulked T&g construction w/dovetailed cleats. That would allow for wood movement and help avoid splitting or cupping. For a non-varnished surface that
sounds like the best system I\'ve heard yet. The biggest problem with hatches is that the oiled top surface will be
wetter than the bottom surface so the boards will want to cup upward. By letting the boards float on the dovetail cleat, each one can cup a
little independently of the others and the whole hatch doesn\'t want to
curl up and eventually split. Each board can curl a little (and will
stayed sealed with flexible caulk). Great idea. I like the non-slip of oiled teak as well.
Plywood is an easy choice. I\'ve thought about making hatch covers out of marine plywood, doing a breadboard style trim on them and a thicker veneer of teak on the top with a balancing layer of teak on the bottom. Thought about sealing the plywood core with epoxy and then epoxy on the teak veneers with a final coating of oil on the veneers. Might make for a good experiment. I would think that even a thin layer of wetter veneer would make the panel curl up, but the panel probably wouldn\'t split and may curl back down when dry. A thicker veneer of teak would allow for wear or sanding.
The other idea I have is to make them out of thick solid teak, route a groove in the bottom surface to accept a tube type weatherstrip that would seal to the hatch opening rim. Next would be to epoxy coat and varnish the assembly. If the piece was thoroughly sealed (and that seal maintained) wood movement from moisture would hopefully be minimal. Having locker lids that seal very well would be a bonus.
The slippery varnish (or 2K clearcoat) finish might not be so good.
I\'ve thought about adding some fine grained non skid to the final coat in some kind of a pattern (like the Vega logo, or just spelling out something like "I spent 3 years thinking about how to build this hatch"
.
So far, other then buying some teak, all the progress I\'ve made is just thinking about how to build the hatches. -Tim
________________________________
From: n4lbl <alan.schulman@...>
To:
AlbinVega@yahoogroups.com
Sent: Tuesday, October 30, 2012 8:05 PM
Subject: Re: [AlbinVega] Cockpit locker hatches
If you get to Denver there is some real marine ply available there. I can
look up where I got my ½ inch (12mm) Joubert (sp?) EU spec ply if you are
interested. It has 4 thin plys length wise and 3 thicker plys with the
grain oriented width-wise. It is okume (?) mahogany-like without any voids
or plugs. Here in Colorado Springs I could buy some ½ inch marine ply with
3 fat plys on the interior and the exterior had 2 thin plys. Plugs were
evident in the outer plys. I chose to drive the 70 miles to Denver.
Perhaps we don\'t care about plugs in the interior of plywood when used for
non-structural hatches. The waterproof adhesive is still comforting.
I only epoxied the edges and Cetoled (a new verb!!) the large surfaces.
Alan
