Recessed Deck Plates

This past weekend was spent working out the requirements for a recessed Deck Plate installation and then sorting through the details and finally working out a repeatable process.

I'm SURE there's an easier way to get this done, but I'm stumped for now...

While I'm not quite "there" yet, I am making some progress towards the goal.

Initially I was thinking I might need a Hi-Density bead of foam for the gasket area to sit against, but that was quickly disregarded after a forced attempt at crushing the plain foam with the clamps failed to do much more than produce a slight dent. Once the plain foam has a layer of fabric over it, this will no longer be any concern.

The next consideration is providing a solid clamping surface for the four clamp points.

... But I'm getting way ahead of myself, it's probably a good idea to list the requirements before running through some solutions.

Note: 

I am assuming that the "top" surface of the foam will be plain while the "bottom" (or back) surface will already have a layer of fabric in place.

1. Bottom surface must maintain vacuum integrity throughout the installation process.
    - This will allow for infusion of vacuum bagging on the top surface
2. High Pressure Clamp Points (x4 for this Deck Plate size) must be a solid laminate to avoid foam crushing
3. Top surface must have a slight "round over" at the rebated area to facilitate fabric lay.
4. Recessed area must provide a flush or nearly flush final installation.
    - In this case I'm much more concerned about lines getting caught under the hatch and ripping it off or toes getting smashed than I am about water dripping inside whenever the deck plate is actually removed.
5. Gap around outer edge not to exceed 3-4mm
    - Again this is to keep lines from slipping between the gap

Probably the biggest issue for me was just working out the router distance, kerf considerations and maintaining the proper corner radius while reducing or enlarging the size of the pattern. Now if I was a cabinet maker of worked with this situation more often I could have whipped some templates out in no time at all using some "tricks of the trade", but figuring it out from scratch really made my brain hurt.

Anyway, after getting things to the point where I was almost on the right track I turned my attention to getting the back side of the middle (chainplate) bulkhead vacuum bagged. I also found a left over piece of foam and applied a layer of glass on one side to serve as a test piece.

Some progress pics below:

First Template.
This one is used to mark the Solid Laminate areas at the clamp points

Clamp points shown

My apologies for a terrible blurry picture of the vacuum bagging

Test Panel being laid up for future use

The three templates that will be used for the entire operation.
I still had to make some modifications during my first test

Test piece of MDF to be used before trying again on the test foam panel

Initial cuts with a hole saw.
These were not removed here, but will be removed on the foam panels and back-filled (outer half) with Hi-Density Epoxy

Second Template accurately placed over the test piece and screwed in place for 7mm counter-sink around the outer edge.
This countersink will serve as the gasket sealing surface.

I had to increase the thickness of the template to account for the top bearing location on the router bit.
I also had to build a "ramp" from the router START location onto the actual work piece.

At this point, the "Pinch Points" would be back-filled with thickened epoxy and the gasket base would be prepared.
All I would need to do now is run a round-over bit around the outer edge before laying fabric over top and proceeding with either resin infusion of vacuum bagging. The center part would be cut out later followed by a layer of fabric around the deck plate perimeter to capture the raw edges (top and bottom)

7mm rebate

This gap will end up being slightly narrower once some fabric is laid in over the top.

The inner cut out is a bit ragged due to the difficulty of cutting MDF and also the fact that I'm cutting around the OUTSIDE of the pattern. I'll see how this works on the foam test panel and may create another pattern to allow cutting on the INSIDE of the template. For now I chose this method to keep any screws or other fastening methods away from "finished" work and only on the areas to be removed.

Final Install

Pretty smooth transition from deck surface to deck plate

Underside