Pressure Box Lid Staining

Knowing that I wanted to have the inside of the lid stained a different color than the outside, I realized that this presented a challenge regarding the staining of the inside edges of the scrollwork.

Trying to figure out how best to accomplish this two-color arrangement without it turning into messy stain bleeds on the inside surfaces, I decided on a certain order of steps I would take…

First I stained the inside surface with several coats of the lighter (pecan) colored stain, then after that was dry, I sanded and shellacked the inside surface several times. The shellac would not only serve to help keep the lid seams airtight, but also to discourage the darker stain from bleeding into the lighter finish - I hoped…

Next, I prepared to stain the scrollwork edges by applying some "Frog Tape" on the inside of the scrollwork area, making sure there were no wrinkles in the tape and rubbing it down to ensure good adhesion to all the thin surface areas around the scrollwork:

Then, I spent about 45 minutes with a tiny brush and gave all the interior scrollwork edges a couple of coats of the darker (red mahogany) stain.

As soon as this was done, I continued with the stain over all the exterior surfaces.

When I pulled the Frog Tape away, I felt lucky that none of the dark stain had bled through onto the inside surface. There was a thin line of the darker stain where the strips of masking tape had overlapped, but it was easily wiped from the shellacked surface with a little bit of mineral spirits.

Now that that's done, I can shellac the outer surface, and then fit the window to the lid...

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Bearing blocks and staining

In preparation for getting the pressure box and lid all sealed up with shellac, I needed to get the interior stained. Before I could do that, I needed to make sure I had the rear bearing blocks glued & screwed into place, so they'd have a unstained surfaces for better glue adhesion.

I borrowed a forstner bit of the correct size to accommodate the ball bearings I planned on using and cut and drilled some bearing blocks that look a little like pipe flanges:

Once I had the bearing blocks stained and attached, I proceeded to stain the interior of the pressure box and the lid in preparation for the shellac sealing:

Now I've got to wait until the stain is fully dry...

More fun with the pressure box

When I compared the pressure box to the lid, I discovered that while the lid was almost perfectly square, the main part of the box was slightly out of square. It also rocked slightly when I set it on a flat table. In order to square up the box, I decided that some mechanical fasteners were in order - I didn't want to rely on just gluing & clamping.
So, I put the lid in place and using some hardwood scraps, I clamped the lid and the box together, side to side and end to end, to forcibly square the side/end assembly (with the already square lid):








Then I flipped the arrangement upside-down, and drilled some pilot holes for some small screws so that they would screw into the centerlines of the hardwood reinforcing strips that were glued to the lower edges of the side and end pieces:








Before gluing, I drove all the screws in to the bottom panel so that the points stuck out slightly and would "find" their pilot holes in the side/end assembly:









I then applied glue to all of the bottom-facing edges of the side/end assembly, set the bottom panel in place and tightened down all the screws:









Once the glue had dried overnight, I found that everything was square and flat, and I got a nice square fit with the box and the lid.

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Pressure Box Initial Assembly

I started putting the pressure box and lid pieces together. Getting everything to line up precisely was a bit of a challenge.

One of the first minor problems I noticed was that the shorter side pieces and tracker bar platform pieces were all just slightly too long to allow the longer sides to fit flush with the bottom and the lid top. Since I had cut them all from a single length of ripped 1/4" plywood, they were all exactly the same amount too long. (about 1/32")

The amount I needed to remove was too small to handle with the bandsaw, and I knew from previous mistakes that hand sanding the end of a thin strip of wood to remove a little length often results in an edge that's less than square.

I remedied this problem by clamping all the pieces together so I could run them over my sanding block and gradually reduce their lengths. By clamping all the pieces together I could keep the end cuts square.

 And here's how the ends looked after sanding. (the one piece that looks shorter is actually a reinforcement strip that had already been glued on to one of the plywood strips)

Once all the pieces had been sized more precisely, it was time to glue everything (almost everything) together.

(Since I'm going to be staining and shellacking the pressure box in a multi-step process, I elected to keep from gluing the bottom on at this point.)

Here's a pic of the lid pieces finally glued together:

Here's the pressure box glued together (without the bottom):

Another view of the pressure box, lid and bottom:

And stacked together to check the fit:

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