Q: What type of moisture meter do you recommend - pins or pinless?
A: If you are drying lumber, you should use the same meter that your customer will be using. On every load, whether it is used by your own company or is sold, the kiln operator should test at least one piece of lumber in every pack with a meter. Then write, with the biggest permanent marker available, the MC that was measured on the side of the pack. This lets the customer know that you checked the MC and that it was correct. Any MC complaints later will either have to show that your readings were incorrect or that the MC changed during storage and/or transportation. (I assume that if your checks showed wet lumber, then you would not have shipped the lumber.)
If you are a manufacturer, the best meter is one that is used frequently. I tested the three major brands of meters on several hundred pieces of kiln-dried lumber, and then oven-dried the pieces to get the "true" MC. All three meters (two pin-type and one pinless) worked very well and were seldom off by more than 1 percent MC.
Each meter has advantages. The pin meter can be used for measuring moisture gradients. (Here's a special hint: If the core is wetter than the shell, the lumber was not dried fully. If the shell is wetter than the core, then the lumber picked up MC during storage.) The pin meter is not very sensitive to differences in species or wood density. The pinless meter can read levels under 6.5 percent MC. The pin meter is also not sensitive to temperature variations, but it is more rapid to use when checking many pieces.
What is the cost to your plant if you ship or use wet lumber or overly dry lumber? Do you have end splits in glued-up panels, joints that open, or flatness problems with finished goods? If you have any of these problems, then I would consider an in-line moisture meter that measures every piece of lumber. I guarantee that it will be a very high payback investment if you can get the wrong MC pieces out of production! (One company I work with went from more than 1,000 rejects in the winter to just three!)
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