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Steaming for the purpose of conditioning.11/27
Recently found a good cheap source for air dried white oak, so I have been steam bending it.
From what i have read about conditioning lumber, a kiln setup should bring the moisture content (MC) to 6-8%. Steam bending creates a MC of around 8%.
So my question is, can I is use my steam bending setup to condition some lumber? Steam it, leave it unbent, set it aside for a couple weeks, then use to make furniture? If this would work, it would cut a lot of time off of simply air-drying it.
Any advice or precautions on this subject would be greatly appreciated.
Conditioning lumber is a process at the end of kiln drying to reduce stress. Your use of this word means something else. I am not sure what you mean
Sorry conditioning wasn't the right word.
Would steaming bring the moisture content down to a usable level similar in a reasonable amount of time?
Injection of steam into the air at room temperature has an EMC of around 22% MC, so steaming injection will dry wood no drier than 22% MC. Dry lumber that is 7% MC at the end of drying that has not been or will not be steamed for bending, is steamed to remove any drying stresses. This steaming, if the air reaches 100% RH, brings the wood up to around 22% MC at the surface and ends, and this moisture increase moves inward with time. That is why conditioning is done in less than 24 hours and only small amounts of steam are added to avoid this high humidity; humidity levels might be around 65% RH or 11% EMC.
To achieve 6-8% MC after bending you need an atmosphere of about 20-25% relative humidity. Heat makes the wood dry faster but not drier if the humidity is 25% RH. Precise values are in wood drying texts.
Note that as wood dries, it increases the air's humidity, so the humid air needs to be exhausted and drier air brought in from outside. Actually, the outside air can be foggy, 100%RH, but itís humidity will drop quickly as the air is heated in the kiln. Alternately, some kilns remove moisture from the air by using a dehumidifier.