Hi All, With a heavy heart, I begin my first posting since the
destruction of the World Trade Center and the attack on the Pentagon.
The only feeling I'd like to express in this venue is that I believe
it's important for our country (and the rest of the world) to get back
to work. However, I will share my personal feelings and opinions
privately, if you're interested.
Today I discovered that Lauter-Humana evidently decided to use copper
inserts for the trackerbar tubing where it passes through the valve
board. This board, which is 1-1/16" hardwood, is devilishly evil to
lead tubing. Although I'm no chemist, I believe the acids in the wood,
coupled with the air passing through the tubes, 'oxidized' them fairly
rapidly (comparatively speaking). Every Lauter I've ever worked on has
weak or completely deteriorated tubing at this particular point. Sadly
speaking, the rest of the lead tubing is usually in really good shape,
and it's kind of a shame that the best way to remedy the situation is
to replace all of the tubing.
In this particular unit, one inch pieces of copper tubing were 'soldered'
to the end of each lead tube. The then copper/lead piece was secured
(glued) into the valve board such that 3/4" of copper tubing stuck out
the 'valve block' side. It's interesting to note that about 60% of the
nipples were still intact after removing the existing valve tubing.
However, a previous technician (or perhaps even the factory) had used
thick clear (or maybe yellow) vinyl tubing, and verdigris (chemical
corrosion) had taken it's toll. Many of the copper pieces either came
loose from the lead or broke at the board when the vinyl tubing (which
was rock hard) was removed.
In the picture which I've sent along, you can also see that as the
years passed, the corrosion got so advance that the end of each tube is
almost completely closed. Surely, this played a major part in the
deteriorating performance of this machine. Although it's not surprising
to me, the valves and pneumatics are still in very good working order,
and they are original. Further, I can't disagree with the owner, who
has chosen not to have them rebuilt at this time.
Another thing I want to report is that I found a very quick way to
remove the lead tubing at the trackerbar. As many of you know, the
manufacture typically used a sealer (or an adhesive) that is rock hard.
Having tried chipping and dissolving (with chemicals), today I tried
heat. After scoring each lead tube, where it's connected to the brass
nipple, I focused a two-inch flame (from a standard propane torch) on
the central portion of the sealer... like in the middle of the stuff.
While I did that, I tugged on the lead tubing firmly. Within seconds,
the sealer softened and the tube came right off. Moving rapidly onward
because the sealer next to the one just removed was still fairly soft,
I was able to remove all of the tubes on one side in less than three
Naturally, I had the trackerbar secured in a vice with rubber covers.
And fearing I might damage the rubber, I couldn't do all 44 tubes in
one shot. However, the far end was cool enough by the time I got 'down
to the bottom' that I simply flipped the bar over and finished the
first side. The second side went even faster because the sealer was
still a little soft. Total time to 'strip the bar clean' was 5 minutes
-- a record time for me! (And substantially less time than it's taken
to write this posting... ;-)
While I was removing the tubing, I took a series of pictures which I'll
eventually use in yet another web page about retubing the Lauter-Humana
trackerbar. I'll also be taking more pictures when I install the new
tubing because it's going to be a little tricky due to all the 'bends'
at the valve board.
Blessings to All,
John A. Tuttle <firstname.lastname@example.org>