This is a multi-part message in MIME format. ---------------------- multipart/alternative attachment I certainly won't say that it won't work, but I have my doubts it will = provide enough accuracy.=20 If your shop is 50% RH at 70 degrees, you will need to warm the hot box = up to about 90 degrees or so to lower the RH to around 30%. 90 degrees = and 30.5% should give you an EMC of 6.0% (I find my hot box is usually = operating in that range). If you have a fluctuation of 2.5% RH both = ways, that would equate to a range of about 5.6% to 6.4% EMC. Yes, if = the on/off cycle was fairly short and the environment spent a similar = time at both extremes, you should have a panel with an EMC pretty close = to 6.0%. But what if 90% of the time it is at 6.4% and only spends a = small amount of time in the lower ranges? However, if you can limit the temperature of the hot box to within one = degree F or so, hot box RH will vary less than 1% up or down from target = and potential MC extremes would be about 5.85% and 6.15%. I haven't made = a careful study of the performance of my thermostat, but it sure seems = to keep the hot box environment at a pretty darn consistent temperature. = Once I set it, I can check, check, check and it is always within a few = tenths of a degree. I think a good fan in the hot box is also important. The one thing that a humidistat has to offer is complete hands-off = environment control. With my thermostat, you do have to manually monitor = the hot box because the first day you put a panel in the box the RH = keeps rising as the wood looses moisture - so you need to turn the = temperature up. But then after the wood looses most of the moisture it = is going to loose, and the hot box has leaked (you do need a vent) it's = excess moisture, you need to turn the temperature down - otherwise you = will cook your soundboard! I just pop a panel in there when I have a = shop day - it's really not any trouble - but you do have to remember to = check it! So maybe it would be a good thing to try that humidistat out. Record its = performance and let us know. I'd sure be curious. Terry Farrell ----- Original Message -----=20 I guess they do that so that it isn't clicking on and off constantly. = If you set it for 30% I imagine it takes it down to 30% and then shuts = off. It doesn't turn on again until it hits 35%. You could set it 2.5% = below your target which would have it fluctuating 2.5% above and 2.5% = below and give you an average RH over time of your target. Since it = takes a certain amount of time for the wood to lose or gain moisture you = would expect the range of the corresponding EMC to be somewhat less than = 5% which would put it in an acceptable range of your target, I would = presume. That's, of course, assuming that they are accurate. =20 David Love davidlovepianos@comcast.net=20 -----Original Message----- That web site states "The differential between the on and off points = is fixed at 5% RH", which means the environment will vary 5%, depending = on where it is in the on/off cycle. A decent thermostat will keep the = environment within a degree or so and thus keeps the RH next to = perfectly constant.=20 I had considered this subject humidistat and others also. I'm glad I = stuck with the simple thermostat. It reall is easy to use and works very = well. Terry Farrell ----- Original Message -----=20 >> I found this humidistat that I would use for a wood conditioning = box=20 >> that seems to be fairly good but expensive ($290). Anyone have any = >> experience with it or can you suggest one that works as well for = less=20 >> $$$. It's the RHC that I'm looking at-scroll down to the second = unit.=20 >>=20 >> http://www.greenair.com/humidistat.htm >>=20 >> David Love >=20 >=20 > If you're conditioning wood for soundboard building, +-5%RH is=20 > pretty miserable accuracy. If you set it at 30%RH and 90=B0F looking = > for 6%MC, you could get anywhere from 5.2%-6.7%. Of course, if=20 > that's just calibration accuracy, and repeatability within a narrow=20 > range is good (which they never seem to think is important enough to = > mention) you can offset the reading and be pretty close. I assume=20 > that's what the mentioned 5% "set differential" is for. So even a=20 > cheap humidistat can work well if it makes the same mistake with=20 > dependable repeatability. >=20 > Ron N ---------------------- multipart/alternative attachment An HTML attachment was scrubbed... URL: https://www.moypiano.com/ptg/pianotech.php/attachments/5a/de/2a/37/attachment.htm ---------------------- multipart/alternative attachment--
This PTG archive page provided courtesy of Moy Piano Service, LLC