Kiln Drying Forum
Wood Drying Topics => General Discussion => Topic started by: kilnguy on December 13, 2011, 08:10:52 AM
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A certain amount of our hardwoods product ships overseas. As of late, the concern has been the temps of our kilns, and if the internal temperature of our wood gets hot enough for 'bug-killing'. The latest and greatest issue I've had is with beautiful country of Malaysia. ;) They want kiln records stating/showing that my maple kilns reach a temp of 165F for at least 4 hours. This is an issue...I dry my maple at a much cooler temp, and my conditioning cycle is only 4 hours long. So, IF I do reach 165F during conditioning, it is for a much shorter time than 4 hours. I am trying to 'think outside the box' of ways to achieve this requirement without compromising the quality of the maple. Any ideas????
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I'm not sure you can get around this one. If you need 165F for four hours, the kiln will have to be at a temperature greater than 165F for more than four hours. Keep in mind that the wood temperature is somewhere between the dry- and wet-bulb temperatures, that's why I say greater than 165F. The only way to know for sure is to measure the core temperature of the wood. This is done by placing a few thermocouples into boards (drill a small hole to center, insert sensor, and plug the hole with a round toothpick is one way). The boards should be the thickest ones and in the coolest spot in the kiln. Your grading agency may have a specific procedure to follow. Mike M.
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Hi Kilnguy,
The others may have much better comments than I, but I would look at these things:
1. Ask for the reference research and materials that drives this 4-hour, 165F "bug-kill" phase, and then study those for potential alternative strategies to achieve the same results.
2. Characterize your actual typical temp/time profile and see how it compares with their requirement; perhaps it is close enough for them to give you some leeway/waiver?
3. Ask them if there is any other alternative post processing treatment method that may be applied to achieve the fundamental requirement.
Sorry, but that's about all I got.
Good luck in finding a solution to this, and please do let us know how it goes.
Tim
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Many operators limit the maximum dry bulb temperature when drying maple to 140 degrees Fahrenheit to insure a bright color. Do they really need that bright color in Malaysia? One alternative as suggested is just heat treat what you are going to ship to Malaysia. To predict what type of color change you are going to have is put a couple of kiln dried maple pieces in a kiln that is drying at 165 or above.