Chemical Damage to D-Chaser Unit

[Clyde Hollinger]

Bill,

I never ran into the situation you describe, nor am I a chemist.  I guess this
is just an affirmation that we really should encourage everyone to use
Dampp-Chaser's Humidifier Treatment, if there is a chance that stuff from
other sources will cost more money in the long run.

Regards,
Clyde

Bill Ballard wrote:

> Dear List,
>
> I'm swapping a Dampp-Chaser system's humidifier heater bar because
> the old one (ca. '93) rotted through. That's right, a couple of
> patches where the aluminum casing of the heater bar is simply
> missing, like lesions. Mitchell at Dampp-Chaser says the only known
> thing to do this is using non-D-C humidifier biostat. Apparently
> anything with chlorine in the tank will produce something in the
> hydrochloric acid family. (One formulation at a local hardware store
> listed ammonia chloride, as active ingredient.)
>
> Apparently this HCl also floats upwards as a gas, rusting string. And
> there is alot of rust on the strings, tpins, and action hanger bolts
> in the top section of this Yamaha M306 Console (42", I believe). I
> immediately suspected water vapor not being properly being spread out
> by the mylar baffle tacked to the underside of the keybed. (The HM-2
> humidifier  was simply set on the piano's floor, and the narrow
> baffle was sitting  maybe 15-16" above the humidifier.) Mitchell said
> that the same caustics put on the heater bar by the wicks was also
> rising upwards from the reservoir.
>
> The lady of the house did confirm the use of non-proprietary biostat.
> She was given an initial 8 oz. of D-C's biostat with the installation
> in '93, and when she asked that technician for a refill he told that
> any humidifier treatment off a hardware store shelf would work. 5-6
> years later, we've got rusted strings and a rotted heater bar.
>
> The piano tuned fine: I would have been the first to complain about
> string friction. The strings do not break. The treble third of the
> action is not in the grip of corroded center pins. There is no damage
> to the wood finish, just steel parts.
>
> The fix is simple. I already have the replacement heater bar, and I'm
> going to scrub the dust off the treble wire and the tpins. I'm
> confident of the wire (because it still tunes smoothly and doesn't
> snap), But I'd like to mic it after scrubbing it. What I do know is
> that whatever wire diameter has been lost to corrosion is not enough
> to fatally increase the wire's tension.
>
> Has anybody run into this situation before? Is anybody familiar with
> the chemistry at work? Is my suspicion that water vapor is the agent
> here, completely baseless?
>
> What Thinkst Thous?
>
> Mr. Bill Ballard RPT
> NH Chapter, P.T.G.
>
> "Lady, this piano is what it is, I am what I am, and you are what you are"
>      ...........From a recurring nightmare.
> +++++++++++++++++++++