Can I dry oak too fast under 15% MC?

[Lostalaskan]

I recently setup a "homemade" DH kiln in my garage. This is my first time playing around with a kiln so bear with me. I air dried some 8/4 red oak and it now reads around 10.5% MC. In reading Kiln Drying Hardwood Lumber, it looks like the lowest step in the given schedule is for lumber under 15%. If I set my dry bulb to 115, my DH will not kick on with its lowest setting of 30% RH. If I set it to continuous operation it pulls a couple cups of water per day and my wood went from 10.5% to 9.5% in about a day. Is this too fast, and if so should I cycle the DH? Any advice would be appreciated, I have some wider 32" slabs to dry next so am trying to use this as a learning experience (without ruining the smaller slabs if possible). Thanks

Kiln - "economical"
Heat - space heater on digital thermostat outlet
DH - big box store scratch and dent



 

 

[K-Guy]

The oak generally at that moisture content won't give up that much no matter what you do. At 8/4 you'll be lucky to get 1/4% a day.

[scsmith42]

The oak generally at that moisture content won't give up that much no matter what you do. At 8/4 you'll be lucky to get 1/4% a day.

Yup.
In answer to the OP's question, it is just about impossible to damage oak below 25% MC.  At 15% I'd say it's a non-issue.

[Lostalaskan]

Perfect, thanks guys. I will leave the DH on until I get to my target of 7%. I am using a Delmhorst analog meter with insulated pins pounded into mid slab, hopefully that is sufficient. 

If I make it to my target MC, do you recommend any last steps other than bring the temp up with no DH to disinfect for a day? Appreciate the advice. 

[scsmith42]

Perfect, thanks guys. I will leave the DH on until I get to my target of 7%. I am using a Delmhorst analog meter with insulated pins pounded into mid slab, hopefully that is sufficient.

If I make it to my target MC, do you recommend any last steps other than bring the temp up with no DH to disinfect for a day? Appreciate the advice.

For sterilization you want to heat the lumber until all portions are 133F or higher.  
With oak, if I have to hit it hard with heat and low RH to achieve the targeted MC% in the core, I will add moisture back into the kiln via a high pressure misting system in order to bring the shell MC% up to match the core MC%.