I'm in furniture business in China. My furniture are exported to the U.S.
We use a lot of Chinese White Birch and Ailanthus(we call this Stinky Chun here) and occasionally Rubberwood. As a well known fact that wood coming straight from most Chinese lumber market are not very well treated or seasoned, primary due to poor drying technique and neglectful storage before sale. So most of the lumber we buy are in higher MC(about 15 to 16%), and we decided to season them again ourselves. I try to locate a kiln schedule for these wood
species on the web but find myself out of luck on this. I'm wondering if anyone have any information in hand about these species?
I'm also wondering if I can successfully bring the MC of these woods from average 15% to 8% with only a forced circulation kiln (or a faned dehumifier)? and what is the proper procedure?
Sometimes, we find that wood regaining significant amount of moisture during manufacturing process and before finishing especially during the tedious rain season in Southern China.
Sometimes, the MC is too high that we even consider putting the unfinished but assembled products back into the kiln for a dehumidification. It did bring the MC down a bit, but is it a right concept of treating the MC in wood?
Please give me some advices.
If the wood you buy is always below 20%, then I think all you need to do is have an equalization schedule. This can be either a dehumdification or conventional chamber that has fans and maintains an EMC equal to your target. It would be good to do that at high enough temperature to assure that the wood is heated to 56C to make sure bugs are killed. You can mix species in this situation where you always start with wood below 20%
Thank you for your hints.
But I'm still a bit concerned of the speed that I should bring the MC down to my target EMC, usually 8%, when majority of my stocks are above 15%. I'm afraid that having the wood droping 7% to 8% in a short period of time might create drying defects. But I just don't know how fast is fast.
On the other hand, do you think if I put some finished products into my dehumidfied chamber in the hope of bringing the MC down 3% to 4% before packing made any sense to you?
If the wood is below 20% when you get it, then you cannot cause drying defects by going too fast. However an equalization schedule will not be that fast anyway. You are creating an atmosphere in the chamber that is at 6% (if that is your goal) and all the wood will eventually reach 6%. Wood that is dryer than 6% will pick up water and wood that is wetter will dry to 6%. It is important to have a way to control both temperature and humidity.
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