Drying times using Pineywoods style solar kiln.

[flatrock58]

I wanted to check with the guys who are using the unvented Solar kiln with dehumidifier like Pineywoods.  I built a similar kiln and want to get an idea what to expect.  I dried a load of pine and poplar that started off at 13%.  It took 6 1/2 days to dry down to 8% and then I sterilized it at 150 degrees for two days.

I have a load of red oak in the kiln now that was about 14% going in.  Should I expect it to take in the 10-14 day range to get to 7-8%?

Thanks,
Steve

[flatrock58]

Well no answer.  It too the load of red oak about 11-12 days to go from 14% down to 8%.  I just started to sterilize today and should be done with this load in a couple of days.  So far it looks like things are working out good.

Now where to put all this wood!
Steve

[69bronco]

Flatrock, what are you using for heat to sterilize?

[doc henderson]

are you trying to regulate temp and humidity to follow a schedule?  or just full bore.  sounds like you are having success.  as you know the oak need to go slower, but mostly at the higher MC.  I assume this was air dried lumber first.  I assume that with no vents, and a de-humidifier, that your temps run higher than most.  are you insulated enough to maintain some heat overnight?  more questions than answers!

[farmfromkansas]

Wondering what you are using to get up to sterilization temperature?

[flatrock58]

Doc henderson.  I went a little slower with the oak.  No real schedule.  I have no vents and use a dehumidifier at night.  I guess I will see what the oak looks like when I get it out in a day or two.  The poplar from the first load looked really good.  Since it was all air dried for a year or more it was down in the 12-14% range.  I did turn off the dehumidifier a couple of nights to slow down the drying.  

farmfromkansas  I used a yellowhammer method.  I had 5 halogen work lights to bring the temperature up to 150 degrees, then it took about 3 to maintain the temperature.  I let the solar part get the temperature up to 127 degrees and then I closed off the kiln and  turned on the lights.  It took about 14 hrs to get from 127 to 150 degrees.

[farmfromkansas]

Did you do anything special to protect your kiln from the concentrated heat of the lights?

[flatrock58]

I hung the lights from the ceiling pointing down between the wood and the door.  The fans are blowing on them.  I have considered putting some kind of shield to keep from heating up the wood close to them.

[doc henderson]

just like solar, paint a little sheet metal black to absorb the heat, and blow the fans across it.

[flatrock58]

Doc that would probably work!