Back at it!

I've been distracted for long enough and figured it was time to get back to the building….

For the last week or so, I've been focusing my attention on the pressure box.

I've been busy cutting out and gluing together all of the reinforcements and various pieces in preparation for assembly, and here are all of the pieces that I've been working on for the pressure box and the lid:

Another view:

Here's the lid put together as a dry fit to see if everything lines up correctly:

And here's a dry fit of the pressure box:

And a detail shot of the tracker bar platform pieces:

I'll still need to drill some holes for the air entry and the take-up spool shaft, as well as for the crankshaft end and the idler shaft.

It feels good to be back building!

(Click here to view this build and others at the John Smith Busker Forum)

Trackerbar tubing

After getting the trackerbar stained with a "golden pecan" color and 3 coats of shellac, I decided I'd try to put some more brass into the build.

Since I'm planning on having a hinged top panel between the pressure box and the pipes, I thought I'd tidy up the wad of tubing that connects the trackerbar to the pipe nipples. I gathered up the 1/4" rubber tubing I had, and after seeing what 15 pieces of this looked like, and how much space it consumed, I wanted to go for a more streamlined arrangement. I searched the web and YouTube and found all kinds of info on bending brass tubing without flattening it or giving it an oval profile in the bends. After trying a couple of test pieces, I came up with a method that seemed to work fine with the tools that I had.

First off, after calculating and cutting the pieces to length, I annealed the brass - first with my propane torch, then after that ran empty, I used the gas stove.

 The idea is to get the brass tubing just to the point where it's faintly glowing red near the area to be bent. It helps to do this at night, with the kitchen light turned off, so the faint glow is easier to detect. After getting to the desired temperature, I then ran the tubing under the faucet to cool it off so I could handle it and anneal the other end.

Of course this leaves the brass discolored, so after the annealing process, I gave all the tubes a good sanding with some 1000 grit sandpaper. It's much easier to polish them up before they have bends in them.

Next I prepared the tube for bending by crimping one end closed with a pair of vise-grips

Then I filled the tube with table salt, making sure it was well tamped in and filled the entire tube. It's important that there is no moisture in the tube, so it's good to let them dry after their post-annealing quenching.

Once the tube was full of salt, I pinched closed the open end with the vise-grips and wound up with this:

Having calculated the measurements for the length and the reference points for the bend radius, I put the tube in my tubing bender, lined up the mark and put a 90 degree bend in it. The tubing bender I bought was a cheap $9 model from Harbor Freight, and I found that giving the tube and the tool a shot of WD40 helped the bender from dragging on the brass too much.

This left the bends with a nice circular cross section all the way around the bend. I wanted to make sure the air path was not obstructed by kinks or sharp turns.( I'm guessing that the travel through the brass tubing will actually prove a little more efficient than the airflow through the rubber tubing, since the brass is smooth inside and should cause less turbulent interference along the way.)

Here's a view of what it looks like from the bottom of the tracker bar. The 5 larger pipes with their 5/16" nipples and tubing will remain as in the plans.

And here's a view from the top. the array of brass tubes is about 2 1/2" wide at the point where it will exit the pressure box side. At the back of the pipe board, the black rubber tubing will vertically connect the the brass tubes with the pipe nipples.

Tracker bar serial number graphic

One more addition. Name, rank and serial number.

Tracker bar notes

Never wanting to leave well enough alone, I got to thinking of ways I could "fancy up" the tracker bar before I stained and finished it.

I thought it would be nice to have little note letters next to their corresponding holes, both as a useful index and as a way to see if I could accomplish "printing" something onto a wood surface.

I worked up the note scale in Photoshop and tried using a bunch of different fonts to see which one would be best. Since my organ is destined to have a "vintage" look, I found fonts that would be both easy to read and yet somewhat old-fashioned.

After getting everything the right size during several test printings on plain paper, I got a sheet of 3M Multipurpose Transparency Film (CG6000) and ran the lettering through my inkjet printer, making sure to specify settings in the print dialog window such as "Flip Horizontal" (to get a reversed image), 600dpi resolution, best print quality, grayscale, etc.

This particular kind of transparency film is made for both laser and inkjet printers. Even though I was using an inkjet, I printed on the smoother/glossier laser printer side, NOT the rougher inkjet side. My testing indicated that I needed to print on the smoothest surface.

Here's how it looked after it came out of the printer.

At this stage, I found it very important to let the film dry for a least an hour or two, even overnight was OK. Trying to apply the lettering too soon will result in smudging. (Fortunately any accidents can be quickly fixed with a bit of sandpaper.)

Being impatient to see the results, I cut out a strip of letters for the smallest 17 notes. The larger 3 notes had a bigger font size, and it would take longer for the ink to dry enough to keep from smudging.

I carefully aligned the strip with the trackerbar surface, and with the ink-side down against the wood, I wrapped it all up in Scotch tape, being careful not to let the strip slide and smudge.

I then used a spoon to rub/burnish the lettering, making sure to move it repeatedly around each area from all different directions. I used the side of a screwdriver shaft to rub the little "flat" symbols, just to be overly safe.

 Here's how it looked when I pulled the film off. You can see that there's very little ink left on the film.

The font I finally decided on was "Maximilian Antiqua", which has a slight hairline shadow on the leading edge of some of the letters. I was happy that this was still defined. Perhaps all that sanding with 1500 grit sandpaper helped.

These are the test pieces I used in my preliminary test. I also tried a couple of different stain colors to see which I liked best, and to see if the stain would cause the inkjet ink to smear - which it did not. I finally got some use out of my failed tracker bar attempts after all.

Here's the final, yet unstained result. I think I'll let the ink dry for a few days before I stain and finish it.