Q: Before I shipped lumber to a customer, I did an oven test for moisture content and obtained values about 6 to 8 percent MC, with one at 9 percent MC. The customer checked the MC when the lumber arrived and found readings as high as 14 percent MC. What is going on?
A: We hope that the customer is using the moisture meter correctly and making the necessary corrections for temperature (with the pin meter, cold lumber readings should have 1 percent MC added for every 20 F that the lumber is under 70 F) and for species (the non-pin meter needs to have about 4 percent subtracted when used with red oak lumber). But even if they were not totally correct, there is still some wet lumber in the load. I think, therefore, that your oven-test values are incorrect.
So, then let's look at your oven test. If you did not achieve zero MC in the oven (oven too cool or time too short), then the MC that you calculated would be lower than actual. Is your oven at 217 F? Did your test take about 24 hours? I hope that there wasn't any other wood, especially wet wood, in the oven when you did your tests.
Another possibility is that your weighing equipment is not accurate enough or is in need of maintenance. Check the weight of a dollar bill. Is it 1.00 grams?
Can you weigh to two decimals? Weigh two small blocks of wood separately and then together. Does the sum of the separate weights equal the combined weight?
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