Hammer steaming

[stanwood]

John Mussellwhite:

>can an over-steamed hammer be restored by ironing?

Yes. The limiting factor is the pressure that you can apply with your
typical ironing tool.  The kind of pressure that made the hammer in the
first place is higher than what you will acheive from a hand ironing tool.

Heat (dry or wet) and static pressure reduces the volume of the felt,
increasing density and reducing resiliancey.  Steam reverses things by
increasing the volume, decreasing density, and increasing resiliancy.  The
cyle may be repeated endlessly.

A comment: Sustained heat above 200f will degrade the integrity of the wool
fibers complex molecular structure and lead to a decrease it's the felts
liveliness.

You also must take into account that steamming causes the hammer to become
slighlty narrower at the top layers.  This is a big reason to avoid heavy
doses of steam.

>I also look after a Yamaha G-2 (in the Banff Springs Hotel) that I've tried
>almost everything to bring down (except fabric softener which I'm extremely
>hesitant to try). Would this instrument be a candidate for the steam
>treatment?

I would stay away from fabic softener it has stuff that leaves residue and
clogs up the felt.  To tell if it is a candidate try a sample by applying
minimal steam, that is in and out of the spout very quickly.  Let it sit for
a few minutes ant check the result.  Assess for tonal effects and changes in
the shape of the felt.  Analyse and proceed.   `

>And finally, a customer has a Steinway M which had new (factory) hammers in
>the seventies but they were never lacquered. The customer complains the tone
>is too bright but the fibres just shred when they are filed and needles drop
>in by gravity. I would juice the hammers first and then file and needle but
>the customer is worried the piano will be too loud and bright after that and
>won't sanction the work. Would steaming help?

Steam only works on felt that has been hardened and densified by heat and
pressure.  In this situation, the steam may have little or no effect.  Just
try it and see if it works.

On an older Yamaha C-7 got great results by: over steaming, then heavy
filing and reshaping then lacquering up.  This allowed the customer to get a
few more years out of otherwise unsalvagable hammers.

Steam needles, vice grips, irons, etc., etc. all exist to help us acheive
a density gradient in the felt that produces the best tone.

David C. Stanwood