Brass Rail Repairs

[BSimon1234@AOL.COM]

Mr. Cole:

I thought the information you provided about annealing brass was just great,
and I am sure that sometime in the future I will follow your instructions and
do it in some project.  Thanks for the experimentation and the write-up.

I was wondering, however, why the piano companies did not anneal the original
rails. As you have shown, they easily could have, and I cannot imagine that
they did not know about it.  Do you think that over time continuous impact
stresses from playing might bend the annealed tabs out of line? You are
gaining a ductility and losing hardness. Do you forsee any downside risk?

I have not yet duplicated a rail on my mill, but I always thought that should
I need to do so I would try to use copper, hoping that it would be stronger,
and get away from the brass annealing question. It would be easier to work
than steel, but still be a step up in longevity from the brass, which I am
sure was used because of cost and ease of cutting.

Sincerely,

Bill Simon
Phoenix
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<<This is a follow-up to the 1902 Kimball upright brass rail repair job. A
few days back, Bill Schlipf had ridden up on his white horse and laid a
perfect set of same-vintage, double-rail beauties on my doorstep. It was
amazing to see not a sign of breakage anywhere. Lurking in the back of
my mind, though, was the thought that they probably would start breaking
tongues eventually and that needed to be addressed.

I had already ordered new butt and damper plates. While I was awaiting
the shipment from Bill, I spoke with several people on the subject of
annealing brass, the upshot of which is that you can easily do it
yourself by holding each plate over the flame of a gas stove until it
starts to glow red a little bit, progressively moving from one end to
the other until the entire strip has had a chance to incandesce, however
briefly. I worked in dim light to be sure that I could see the glow.

Before I annealed the "new" pieces, I experimented on one of the broken
ones. I treated only half of it and left the rest untreated as a
control. I also wanted to see if there was any danger of melting since I
heard that annealing and melting temps are not that far away.

On the softened part, I could bend a tongue up at a 45 degree angle,
down to a 45 degree angle, then back to horizontal without any sign of
breakage. I did this on several tongues and saw vicegrip marks but no
sign of breakage. I then tried the same test on the unannealed part. The
tongues would start to break on the upward bend and would completely
break off at the downward bend. Holding the brass over the flame for a
long time did not cause the part to melt. However, if your stove
temperature is hotter or you are using some kind of a torch, it would be
wise to experiment on the old part first.

I just reassembled the action today. Now I have some confidence that
this family heirloom will live a long life.

This was an unusual situation, to be sure, but I thought the discoveries
I made about annealing might be of general interest.

Tom

-- 
Thomas A. Cole, RPT
Santa Cruz, CA
mailto:tcole@cruzio.com

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