Best way to dry burls?

[dirk martin]

I've got 3 nice burls (red oak, cherry, other) that have been sitting in the rain, since they were cut.
Not sure what I'm going to do with them.
My plan is to stabilize them and make some worthless wood blanks and some knife scales....but not sure.
So, I need them bone dry.

What's the best way to dry these?
Just set them on a shelf, inside my house, and wait forever?

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[John K Jordan]

I've got 3 nice burls (red oak, cherry, other) ...My plan is to stabilize them and make some worthless wood blanks and some knife scales....but not sure.
So, I need them bone dry. What's the best way to dry these?

I cut and dry a lot of green wood. I have no idea of the "best" way to dry but I can tell you how I do it.

The only way I know to dry something fairly large is to section it into smaller pieces then Anchorseal the ends and any wild grain. This way the pieces have a chance of surviving. I usually seal pieces cut from burls on all faces.

I usually cut pieces from logs and burls into spindle turning squares, blocks, or bowl blanks 2 or 3" thick, occasionally up to 4" or more. Something bigger should probably be turned green. I section offcuts into pieces as small as 1" square.

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I stack pieces loosely on wire shelves and let them air dry in the (heated/air conditioned) shop. This takes a lot of space!

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Small turning squares will air dry in a few months to a year or so depending on the wood. Some species take longer. Larger pieces take much longer. The dogwood, persimmon, holly, bradford pear, and cherry I'm using now has been air drying since 2006-8. If I cut a little each year after a while I have a abundant supply of very dry wood. Note that many exotics you buy, especially those with heavy wax all over, are also wet inside and have to dry for a long time. (I sometimes scrape most of the wax from the sides of some exotics.)

After the wood has dried enough to quit warping I like to put it back on the bandsaw and clean up the sides. This removes the warp but more importantly, reveals any surface drying defects that I either cut away or mark with a red sharpie so I won't be unpleasantly surprised with I cut into it.

After they dry for a few years in stacks I sometimes dump them loosely into tubs to free up shelf space. After a few more years I move them to my working storage. I think I have enough wood now for three lifetimes of turning.

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JKJ

[dirk martin]

I think what I'm going to do is use Alumilite casting resin, and make knife scales and duck call blanks.
So, I would think my first task would be to cut the burl down to the the proper size for the blank.
Next, do you think I can simply place them into a toaster oven and cook 'em dry?
When I take them out of the toaster oven, should they be placed into an air tight container, as they cool, until I am ready to cast them?

[John K Jordan]

I think what I'm going to do is use Alumilite casting resin, and make knife scales and duck call blanks.
So, I would think my first task would be to cut the burl down to the the proper size for the blank.
Next, do you think I can simply place them into a toaster oven and cook 'em dry?
When I take them out of the toaster oven, should they be placed into an air tight container, as they cool, until I am ready to cast them?

No, a toaster oven makes too much heat and will dry too quickly and can cause warping and cracking, even with small samples. If you read up on kiln drying you'll see it requires careful attention to controlled heat and humidity.

Many people dry small samples with a microwave oven, though. You still have to be careful - zap wood on high and it might burst into flame or at least smoke and be charred inside.

I've used the microwave successfully in the past, long time ago. You might want to use a microwave oven you won't get beat too hard if you leave it with funny smells. It is also best to have a good scale for weighing small things. You need some patience too. Search the web for drying wood with a microwave oven and read enough different approaches to try to weed out the nonsense. This is the way I did it:
- Carefully weigh the piece and write down the weight
- Warm in the microwave. This doesn't take long but I don't remember the time/power enough to give a guideline Do not overheat!
- Let the piece cool completely
- Weigh carefully and write down the weight
- Repeat
Each time you weigh the weight should change. As the wood dries, the weight will change less each time. Finally the weight will not change at all and the piece is dry.

I highly recommend cutting the blanks somewhat larger than you need so you can trim them if they warp. The wild grain in some burls can cause significant distortions.

You will want a scale that measures in grams, or 1/10s of grams for small pieces. If you don't have a suitable scale there are many on Amazon and they are quite cheap. Get one with the maximum weight not a lot greater than the maximum weight of the pieces you expect to weigh. I have one that only goes up to 100 grams but this is the one I use the most in the shop, for wood, glue, bottling honey, etc: https://www.amazon.com/gp/product/B002UEZ2FC It will weigh to 11 lbs but seems pretty precise for small weight differences.

BTW, with a good scale you can also measure the absolute moisture content of a piece of wood by the "oven dry" method. This is a destructive test but is far more accurate than a moisture meter.

Another way people dry wood is to build a "kiln" from a box such as an old fridge. Use a lightbulb for gentle heat. For example, noted woodturner Cindy Drozda has instructions. Ask Google to look up cindy drozda kiln for that and much more.

Some people swear by the denatured alcohol method for accelerating drying. The process is basically soak the wood in DNA, let it dry in air. Results may vary. After my initial testing I do not use this. Might be OK for very thin wood.

Note that wood cut thin enough for knife scales will dry very quickly just sitting out in the air. You can use the weight method here also to check for dryness. This takes more patience but doesn't risk burning or overdrying.

If you find your pieces warp badly while drying there is another thing that can help. Look up boiling wood stephen russell. This is a time-proven method to combat instability. A guy in Peru who sold exotic wood blanks and bowls around the world told me they boiled every roughed out bowl. Nearly every madrone turning blank you buy will have been boiled since it is notoriously unstable.

You will need to follow the Alumilite instructions for the suggested dryness.

JKJ