Drying turning blanks

Dave Black

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638
Location
Central PA
I am getting started turning more things since I have a newly made big lathe to play with.
http://familywoodworking.org/forums/showthread.php?36232-Shop-built-large-lathe
I made a ball turning jig and made a few balls from some largish scraps I had around. They came out pretty and I wanted to make some more. I am wondering what the best way to dry the wood is. I have cut some sections of branches of various downed trees from the around the farm but now I'm wondering the best way to dry them. The finished ball sizes I want to make are anywhere from 3" to 10". I tried to rough out the shape and let them dry but they all crack within a few days, which I suspected they would. Is there a fast way to dry them. Some things I have at my disposal are, a microwave, a vacuum pump and (finishing up a vacuum chamber), DNA although only a gallon but I can buy more. What works best? I am not a terribly patient person when it comes to finishing a project I start so if there is a fast way to dry them that would appeal to me. If theres not a fast way then I would probably prep a bunch of blanks then try to forget about them for a while. Should I consider stabilizing these either because of the thickness or because of the type of wood. I have some pretty cool spalted walnut laying in the woods from limbs/upper trunk from a tree I took down 5 or 6 years ago. What do you guys do?
 
Dave, I use a kiln I built myself that uses 2-5 125w brooding lamps for the heat. I have a switch set up that allows me to turn on any where from two bulbs up to 5 for maximum heat. The kiln basically looks like an outhouse. I have 4 drying racks in it. I usually give the bowl blanks a coat of walnut oil (or if I'm low on that some boiled linseed oil). This helps with minimizing the checking of the wood. Especially softer woods like cottonwood or hackberry. Red Oak is a harder wood but will check out badly if you're not careful. I also weigh each blank and mark it with pencil on the blank to monitor progress. Never had much luck with those moisture meters, always seem to lie to me. But I can put a large pecan roughed out bowl in there with 3-4 bulbs going and it will be ready to finish in about a week. Dries nice and evenly with minimum cracking. You might want to give that a try. You can build you a smaller one if you want. I like being able to have drying at any time 14-20 blanks when I'm really busy. DNA helps for air drying. Never messed with the vacuum stuff. I built my kiln for only about $150.00 and have been using it for years. For the money I think the kiln was a good idea for me, anyway.
 
I don't have a kiln, would love to have one, but I would think bowl, rough turned, would dry differently than the ball blanks.... I'm assuming the balls are solid wood. I don't dry a lot of wood, but if needed, I have an old Monkey Ward's microwave in my shop that I'll cycle wood through if it's really wet.... 3 minutes in the MW, on high, cool it to atmosphere temp, then cycle again, until it feels dry... you can do the weight thing if you really take the time, but I usually just cycle a few times it until it feels dry... I have a moisture meter, but like Dave, it's a liar about half the time.

I've used the DNA method a few times, not much luck with that... but I do have a 5 gallon bucket under the work bench with a couple of gallons of DBA in it.... probably need to look at it to see if I still have any in there... haven't opened the bucket in about 6 months or so.

I'm not quite as sophisticated as Dave with my turnings... sometimes I just follow Grumbaugh's advice... turn it green and let it warp.
 
Do these branch sections still have the pith in them? If so, it's likely that any drying method will still end up with cracks.
 
Do these branch sections still have the pith in them? If so, it's likely that any drying method will still end up with cracks.

Yes they do have the pith still, I was wondering about that. I can cut blanks from larger stuff without the pith but that narrows my wood options a bunch. Plus the balls look really cool when it's centered on the grain pattern.
 
The only thing I've heard of that hasn't been mentioned here is boiling. PEG, DNA, and boiling (as in a big propane lobster pot or even steel drum on a big propane burner, for a couple hours) all are attempts at breaking the cell membranes down to let the water out. But, I've never heard of anything that works every time for every one. If I felt it was something I really had to do I'd boil for two hours, drip dry, then soak in DNA for a day. I still doubt if you would get it dry close to the center of a 10" ball. I've also read about a guy who does really big turnings that built his own microwave that rotates the turning inside, turning on for 3 minutes every hour. While huge, 6 ft high by 2 ft around, they are hollow forms to not as thick as yours.
 
Don't know what else to tell, Ken. Gotta look at it this way. It took a while for Mamma Nature to get the wood green and wet and all that good stuff. You can't expect to get it dry overnight or in two days. Drying wood takes time and unfortunately, patience. Good luck with your goings on.
 
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