Pressure box seal

On to the pressure box seal…

I wanted to try a leather seal for the pressure box, so I gathered my scissors, contact cement and a strip of split leather.

First I laid the leather strip over the rim of the pressure box and cut it to approximate length, leaving a little extra for final trimming.
I found that the scissors didn't work nearly as well as a new razor blade. The razor blade was easy to push down and make a straight clean slice. I cut all the corners at 45s.

I then applied contact cement to the rim and the cut strips of leather, waited about 10 minutes then pressed the strips into place.

For the rim of the lid, I chose to go with chamois, but since I didn't have it in a nicely cut strip like the leather, I had to first make my own strips. I have a rotary paper cutting board, and I found that it did an excellent job of making straight cuts through the chamois.

I repeated the length cutting and cement process and here's how it looks:

Overall, it seems to only add about an 1/8" (at most) to the height when the lid is in place:

If it proves to be an adequate seal, I'll probably stain the ouside edges to match the exterior a little more closely. If it doesn't work well, I guess I can razor-blade it off and try a more synthetic alternative.

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Mounting the tracker bar and fitting the tubes

Now that I've got the pressure box window installed, I'm eager to see whether the pressure box will indeed hold any pressure.

Since I've got no holes in the back or side panels, the only places where air can leak are: around the take-up spool shaft, the tracker bar base, the lid seal, and the lid window seal. Of course there could be leaks around any of the panel joints as well.

Since I've put an oil/air seal around the take-up spool shaft, that should be OK, and I'm fairly confident in the 4+ coats of shellac on all of the wood panels and joints. So, I decided that the next step was to get the tracker bar mounted.

I drilled the tracker bar base ends and used it to mark corresponding holes in the tracker bar platform, then I fitted the bottom of the tracker bar with some strips of foam weatherstripping (coloring the grey foam black around the edges with a sharpie).

I attached it with some brass machine screws and nuts:

Then I fit my crazy brass tubing to the bottom side of the tracker bar:

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