Piano World Home Page Forums Our Most Popular Forums Piano Tuner-Technicians Forum Yet Another Dampp Chaser Question...

Yet Another (stupid) Dampp Chaser Question...

Ok, so I have this ancient 1918 Hobart M. Cable upright that I'm slowly, but surely restoring. It is in the coastal California fog - where it has been since at least 1963.

My interior humidity is centered in the high 50s, ranges from 45 to 70% *at this time*. In the winter, it probably falls a bit as the heat comes on.

Should I install a DC rod with Humidistat? Or just leave well enough alone? The piano is in remarkable shape - the soundboard looks perfect as far as I can tell, and I credit the relativly high RH with that.

From what little I know, I'd think this is a borderline situation at best, and probably depends more on what happens this winter (To Be Determined) than the higher than ideal RH if it is constant - although the strings do have "some" rust (not excessive, quite remarkable for an 87 year old piano) - still some shinyness to them. If the interior RH dips this winter, perhaps the DC rod/humiditstat would give me better tuning stability.

I'm also afraid, since this piano has been in this environment for at least 42 years, that adding the DC unit might adversly effect glue, felt, and other bits.

Discuss please...

Anyone?

You gave the answer yourself. The piano is in remarkable shape, soundboard perfect. I wouldn't dry it out with a heat rod. It's doing great as is, leave it alone.

kpiano

The dc rod is not going to dry it out, It will remove the excess moisture and make the piano more stable. Once rust has started it can not be magically removed by a d/c but a d/c will he;p slow it down and even prevent it from showing up in other aread. The rh safety range is between 40-50% for a piano so if you are in the high 50's and go as high as 70 you are outside the zone. I recommend you go to the DC web site and read a little more as well as check past posts on the subject. There are many reasons why the wood has not changed on the soundboard- quality of construction, glues, design etc.

Where is the rusr you have on the strings ? It it on the coils, copper windings on bass strings? tuning pins? bridge pins ?. Also what is the the pianos pitch and tuning pin torque ?
Are you having problems with the tunings ?
Keep in mind that a properly installed dampp chaser has a humididistat control that will maintain the r/h. A D/c can help the action parts and keys as well.

Go to Home Depot and Radio Shack and take daily readings at various hours of the day and night to monitor the piano

I second the suggestion that you go to the Dampp-Chaser website and learn about how the devices work. A DC system will lessen the humidity-related stress on your piano rather than increase the stress.

You may have a fundamental misconception about the adverse effects of high vs. low humidity on wood. High humidity over time increases the moisture content of wood. Wood with relatively high moisture content has lower strength than wood at a lower moisture content; structural damage to wood occurs mostly under conditions of relatively high moisture content with the combination of the swelling of the wood and its reduced strength and greater vulnerability to crushing. The damage usually becomes visible as the low humidity seasonal cycle arrives and the wood loses much of its moisture content.

A final thought: your soundboard may look perfect, but it still may well be dead: does still have some crown? Is there any sustain? Have you looked at the board in in winter (when the relative humidity may be lower); soundboard cracks will usually be visible then. Cracks themselves may not matter, but in an old piano they are often evidence of a dead soundboard. Remember that your piano did not live all its live in the relatively piano-benign coastal redwoods; it was no doubt built, and probably had a long career, on the east coast or in the midwest where the summers are very humid and the winters are very dry.

The rust is mostly confined to the coil area, although the rest of the strings are dull looking, like there is ultra fine rust on them yet shinyness comes through too - make sense? Tuning pins and bridge pins are about the same - dull. Copper windings are blackish.

Tunings are still an unknown - I have one more job to do on this thing before I call a tuner. I can work on this thing, no problems, but tuning I leave to the experts beyond touching up a unison here and there...

Ask the tuner what he thinks about the need for climate control in the piano. From your description there is no rapid deterioration do to excessive moisture. Don't treat somthing that is not there. Where you live is one of the most stable areas in the world for temp and humidity. Only if you are right on the ocean and can smell the salt in the air would I worry.

I disagree wiyh JimBob. If you reduce the moisture content in the air surrounding the piano, the MC of the wood will go down. I call that drying out. Semantically you could call it removing excess moisture implying it never gets completely dry. Technically it already is dry. Right now the wood has been swollen to the point it is for at least 40 years. Reducing the moisture content now is likly to cause separation of parts. The humidity it is in now is not causing separation of parts. That usually occurs because of fluctuation of humidity or excess humidity. Putting a heat rod in the piano now would be a fluctuation.

kpiano