Guidelines for Successful Thermal Modification Pt. 3
14. Pre-stack lumber to save on setup time – Do not let your thermal modification kiln sit idle while waiting for wood. Have next wood load ready before the current modification cycle is finished. As soon as the wood inside the kiln is done being modified and taken out, having wood ready to go in immediately will help reduce kiln downtime. To speed up transfer of moisture and heat sensors from outgoing to incoming wood into the kiln, you can use chalk or colored crayons to circle or mark around holes where heat and moisture sensors go in the wood. Chalk or crayons will ensure the sensor locations visually stand out when you transfer the sensors of the outgoing load into the new one. The more prepared you are, the more kiln downtime is reduced.
If wood is ready to go in as the other load is removed, kiln downtime will be reduced
15. Keep records of initial moisture content and wood temperature – This data (along with wood thickness, species, etc) can then be used to support statistical analysis to forecast future processing times. This also helps with production scheduling particularly when different sized, different wood species are required. With so many variables such as species, thickness, initial temperature, initial moisture content, surface quality, etc, you need as much data as possible to plan for the processing schedule priority during peak demand periods when the ThermoWood TM kiln is operating at 100%.
16. Analyze wood boards before and after for quality control – Before the wood is modified, take photographs of wood to compare the quality of the wood before and after being processed. After the modification process is completed, cut sample boards to determine if modification is affecting internal checking and if so, to what degree. The boards should be cut at an angle to see if the checks can be found. Depends on whether checking occurred or was amplified on the wood, the drying phase can be modified in the future. If checks are found then the drying phase might be carried too rapidly. This would require slowing the process down. If no checks are present you may be able to speed the process up without adverse effects.
When analyzing boards for checking it is always good practice to inspect wood before it is thermally modified and after, so as to confirm that there if there is checking post-modification it is not from pre-existing internal checks.
17. Remoisturize wood to keep it from becoming too brittle – The patented ThermoWood process has the thermally modified wood reheated to pull moisture back into the wood. If the wood is too brittle or is checking afterwards this phase needs to be modified.
18. Block partial loads at ends to maintain consistent air velocity and flow through the load – Quality consistency of thermally modified wood within the same batch and on to the next requires strict control of air flow. If the air flow is consistent and even across the load then the temperature can rise evenly and this will be noted by your heat sensors.
19. Sticker wood within the plane of the loading cart – Place stickers that extend from width to width of the load but not beyond the width of the cart. Stickers that extend past the width of the load can cause interference when the cart is being loaded into your wood thermal modification kiln. Also ensure that lumber does not extend past the length of the cart or you might now be able to close the thermal modification kiln door.
Ensure wood does not extend past the width or length of the cart or interference might occur when entering the kiln or closing the door.
20. Invest in quality stickers – It is best to use aluminum stickers as these will not stain the wood as much as wooden stickers. If aluminum stickers are out of your budget, use wooden stickers. Do not use plastic stickers as these will melt from the high temperatures experienced inside the kiln.
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Aluminum stickers are more durable and also do not stain the wood during thermal modification.
