The Forestry Forum

General Forestry => Drying and Processing => Topic started by: Faron on May 11, 2006, 11:01:35 PM

Title: Dehumidifier
Post by: Faron on May 11, 2006, 11:01:35 PM
I have to store some kd hickory in my open , gravel floored sawmill building for a while.  (No room in the shop)  I have raised it off the ground and put plastic under it.  I then covered it with plastic, and placed a home dehumidifier under the tent.  Will this maintain the lumber at about the right moisture, and what humidity should I keep the dehumidifier set at? 
Title: Re: Dehumidifier
Post by: beenthere on May 11, 2006, 11:47:26 PM
It will depend on the temperature, I believe, and what moisture content you are going to try to maintain.
Title: Re: Dehumidifier
Post by: scsmith42 on May 12, 2006, 09:21:28 AM
Faron, the short answer is that it depends upon what you want to do with the lumber (framing, furniture, or flooring).  Framing lumber is usually kept around 16%MC, interior lumber around 6%.

If you'll provide me with an average temperature, species, and targeted use, I'll look up the recommended RH that will maintain the MC%.

Scott
Title: Re: Dehumidifier
Post by: woodhaven on May 12, 2006, 08:33:17 PM
Faron.
What you have done is created a kiln and all precautions that apply one also apply to you. There are many charts on the forum about MC versus humidity and are easy to read. Bottom line is it will work.
Title: Re: Dehumidifier
Post by: BBTom on May 12, 2006, 08:39:42 PM
Generally speaking 35% humidity if I am not mistaken.
Title: Re: Dehumidifier
Post by: Faron on May 12, 2006, 09:40:51 PM
Hi, guys,  This is hickory dried down to 6%. I'll be making flooring out of it just as soon as I can get it in the shop-at least by the last of the month.  The dehumidifier reads temp and humidity, and you can set the target humidity.  Essentiallly I am just trying to keep the humidity around the stack at about the same as it will be when it gets in the house.  Daytime temp lately has been in the 60's, hopefully getting into the seventys sometime next week.
Title: Re: Dehumidifier
Post by: scsmith42 on May 12, 2006, 09:53:38 PM
Faron, here is the breakdown.  At 70 degrees F and 35% RH, your EMC will be 6.2%.  At 70 degrees F and 35% RH, your EMC will be 6.9%.  Regards,  Scott

   EMC % chart   
      
Temp (F)   30% RH   35% RH
50   6.3   7.1
70   6.2   6.9
90   5.9   6.7
Title: Re: Dehumidifier
Post by: Don_Lewis on May 13, 2006, 06:38:23 AM
You will have to keep it quite warm to maintain 35% RH. The coil would freeze up if you try it at 70F. It is easier and cheaper to simply run a heater on a humidistat and keep the air warm enough to have the humidity stay at 35%. This isn't a good application for a dehumidifier.
Title: Re: Dehumidifier
Post by: Faron on May 15, 2006, 09:49:51 PM
OK. Thanks, guys.

Faron
Title: Re: Dehumidifier
Post by: iain on May 21, 2006, 04:56:39 AM
Dead stack it off the ground and wrap it tight with plastic (damp proof membrane is good)
it will not move in a month like that, it will move more in your shop as you machine it


Iain