# Trying to determine if my olive wood blank is dry



## Quickstep (Apr 10, 2012)

Last year, I started a pepper mill from an olive wood blank and discovered that it was wet. I turned it to a 3" round and set it aside. So, here I am a year later, hoping it's dry enough to have another go. I calculated the volume and it's just about spot on for the 62 lb/cu-ft density of dry olive wood, but I know there are lots of variables there. I weighed it, put it in the microwave for a minute and weighed it again. The weight didn't change. But, after it came out of the microwave, a crack emerged. Does this mean it's still wet?


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## BigJoe16 (Feb 20, 2012)

Did you weight it as soon as you took it out of the microwave? 

You should wait a little and then weight it so the moisture has time to come out. 

If you have a small scale, weight it now and wait a week or two and see if it has changed after taking it out of the microwave. 

If I had to guess, I would think that a blank that small after this long would have dried. But I have no expericane with olive wood.


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## Oak Tree Woodworks (Mar 25, 2010)

Rule of thumb is a year for every inch of thickness plus one year. A moisture meter is a good investment they can be found for $20 up to over $100. Invest in the high price unit and it will last you for many years and will pay for itself to avoid issues as yours.


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## DonAlexander (Apr 12, 2012)

I've done a fair amount of experimenting with drying wood in the microwave over the past 4 months. Cracking hasn't been an issue but I have not tried olive wood yet. My very limited experience with it after a trip to Israel and picking up some olive wood trinkets is it's prone to crack (and I don't think the trinket sellers dry their wood much...they want to sell stuff fast, if it cracks when you get home, too bad). Anyway, I'd guess your wood had built up stress from drying and was nearly ready to crack. Microwaving it was just the straw that broke the camels back.

You didn't say how you nuked the wood, only that you did it for one minute. My assumptions is that was one minute on high. If so, what I've discovered is starting out with a longer (3-5 minutes typically) at a lower setting (40% or less) gets the best results. Counter intuitively, the dryer wood is, the hotter it gets at a give time-power setting. I always take the temperature of the wood immediately after the microwave finishes. I use an IR heat sensor and measure several places. I want a time-power setting that will give a surface temperature of about 150 degrees F or less. If I give a piece of wood 4 minutes at 40% power and get 150 degrees F, and let it cool completely, then reheat at the same settings, odds are the temperature will be 160-170 degrees F. I initially thought I'd mis-recorded something. With fewer water molecules to excite, I expected lower temperatures. It never has happened that way. So I'm guessing that if you cooked 16 oz of water to 150 degrees and then used those settings to heat 8 oz of water the water would be hotter than 150...I really need to verify that but that seems to be the case - less water in the wood means less time and or power to heat it.

What I've found is when wood comes out of the MW it will have lost some weight but depending on species, not always a lot. As it cools off (no visible steam at 150 deg. F) it continues to lose weight. I always cool the wood either to room temperature or at a minimum to <80 deg. F. After a day, I've found that wood that is reasonably dry (10% MC or less) may increase in weight, stay the same or lose weight - I think its just finding equilibrium with the ambient humidity.

You might want to read up a bit on what happens in kiln drying wood as I think there are some parallels in the MW. Just because the wood doesn't ignite (and I've done that, too) doesn't mean you have not gone too fast with the drying process. My first rule of thumb is don't create steam - no visible steam and no hissing. My second rule isn't much of a rule but get a moisture meter and measure what's happening on the surface and a scale to measure how much water you're losing. It generally takes me 2 to 3 days to dry wood slowly and sometimes 4 days. Some folks ask what's the rush and other folks think that's too slow. For me, drying wood in 2 or 3 days is a heck of lot faster than waiting 6 months to 2 years for wood to dry.

Don


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## Quickstep (Apr 10, 2012)

So, I've nuked this blank 5 times and it's lost 3 grams. 

I weighed it in September and it weighed 1389 grams
Before I started microwaving this week it weighed 1386 grams
After 5 trips in the microwave it weighs 1383 grams

When it comes out of the microwave, I don't see steam or anything like that, although there's a crack that gets wider and longer with each time it's microwaved. 

Should I turn this thing, throw it back in the pile for another year or convert it to heat?


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## Bonanza35 (Jan 20, 2011)

I don't know olive wood but I would think a 3" round would be pretty close to emc after a year, provided that the ends weren't waxed. That being said, it only lost .4% of its total weight even after nuking. So if it was noticeably wet before then that condition hasn't changed significantly. Are you sure it was wet a year ago? .4% weight loss is almost negligible IMHO. 

Also, how bad is the crack? Will it turn out or is it running into the designed piece?


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## DonAlexander (Apr 12, 2012)

It's really hard to say with any certainty but my guess is you olive wood is dry. Time and the lack of weight loss are in your favor. That growing crack would suggest you are still drying it. Over-all, my guess is your blank is at or near EMC. Be careful with the crack you can see - there may be more you can't see.

Don


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## Quickstep (Apr 10, 2012)

For now, the crack is small enough to be filled with CA. Right now it's not in the section of the board I need, butI wonder where it's going. 

Definitely wet last year. When it turned it round, there were continuous streams of shavings soaring over my shoulder and they were definitely wet.

I might cut it to length and drill out the center and see what kind of shavings I get.


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## Quickstep (Apr 10, 2012)

Well, I cut it to the 6" length and drilled a 1-1/16" hole through the center. The shavings seemed dry, but were very fragrant, as if the wood still has a lot of sap in it. Should olive wood be conspicuously fragrant when it's being machined? Now that it's drilled, do you think a few more trips in the microwave could hurt?


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## Oak Tree Woodworks (Mar 25, 2010)

Quickstep said:


> Well, I cut it to the 6" length and drilled a 1-1/16" hole through the center. The shavings seemed dry, but were very fragrant, as if the wood still has a lot of sap in it. Should olive wood be conspicuously fragrant when it's being machined? Now that it's drilled, do you think a few more trips in the microwave could hurt?


Ohhh yes the fragrance is one of the pleasures of Olive wood. Perhaps after 10 years not so much. 

Just remember this old saying. The hurrier you go, the behinder you get.


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## DonAlexander (Apr 12, 2012)

Quickstep said:


> Now that it's drilled, do you think a few more trips in the microwave could hurt?


That depends on how dry the wood is now. I would highly recommend getting a moisture meter and testing the wood. They start at about $20 and I found mine at Lowes. Is it 8%, 10%, 12%, 15% or more M.C.? A meter will tell you all we can do is speculate.

Don


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