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.