Drying in my solar kiln

[briand7878]

I recently built a solar kiln and placed a bunch of walnut and red oak in it. As the time goes by I notice that the humidity in the kiln gets less and less which Is how it works I believe. Right now it's 138 inside with 15% humidity. I leave the vent open a little bit as directed but I'm not sure if it's getting too dry. Do I need to do anything to tame this beast? I haven't been inside to test the lumber, but there is no chance it's totally dry already.

[scsmith42]

How long has the lumber been in the kiln?

When was the lumber milled?

How thick is the lumber?

How accurate is your RH% measuring device?

[briand7878]

How long has the lumber been in the kiln?

Since August 22nd

When was the lumber milled?

August 21st

How thick is the lumber

1" quarter sawn red oak.

How accurate is your RH% measuring device?

I have no idea, it's an accurite thermometer but seems to be working well.

[scsmith42]

In a nyle kiln I typically run 4/4 QSRO for 5-6 weeks (about a week longer than FSRO).

In a solar kiln it is usually twice that time, due to the fact that it's only operating 12 hours a day or so.  Usually I leave my vents totally closed when drying QSRO in a SK and allow the small amount of leakage to exchange the air.

So from a QSRO standpoint, your drying rate seems very fast.

IF it were me, I think that I would close the vents totally and allow the RH% to increase inside the kiln for several days, so that the surface MC% will not be too low.  

I'd also check several boards with a pin type moisture meter - driving the pins in 1" from the edge of the boards.