I just want to ask this...

rough turning green wood

jeff jilg

>I prefer to create nearly round pieces so I do not typically take a piece from green wood to very thin finished piece in 1 day.

I rough turn all my pieces from green wood. Then I paint undiluted Anchorseal (wax) on the roughouts. This causes the drying process to be lengthened, and at the same time that slow process reduces or eliminates cracking.

Since the piece looses moisture at a uniforum rate from the outside walls and the inside of the wood, the process is pretty stable. It may not be high tech, but it's a tried and true method that many have used for quite awhile.

In general the process takes ~1 year for a 12" bowl. And it can take 4-6 months for 6" and smaller bowls. If you're not in a hurry it works. Once you get a stack of bowls drying out you'll end up with enough stock over time unless you're doing major production work.

The one wood that is difficult here in Austin, TX is oak. We have millions of oak trees and they get trimmed and cut down all the time. But the darned stuff would rather crack than become a nice salad bowl. As a result, many or most of the local turners including myself no longer mess with it. However I've used about 15 other woods including ash, cedar elm, hickory, pecan, hackberry, chinaberry, and others. The process works fine on all of them.

Re: I just want to ask this...

Barry Irby

>I agree with everything Jeff said above. The usual rule of thumb is to turn the rough bowl and leave it about ten percent of the final diameter for the rough wall thickness. A ten inch bowl would be an inch thick and a twelve inch one could be an 1 1/4. The second part of the rule is to let them dry for a year per inch of thickness.

I usually do not anchorseal my bowls, but I stuff them in a brown paper bag (grocery bag), sometimes adding a few wet shavings and roll the bag shut and set them aside. If I'm being a good boy, I label the bags with the contents, species, weight, etc.

Another answer to your question might be to accurately weigh your blanks and record the weight and dates. A postal scale will do it. Mine will weigh things up to five pounds. Weigh them once a week or once a month. When they stop losing weight, you can turn them. Sometimes and with some woods it might be as little as two months. I write the date and weight on the blank on the chuck foot that will get turned off later, or you could just use a piece of paper attached to the blank.

Re: I just want to ask this...

DWFII

>What's the percentage of success/failure with the brown paper bag and wet shavings technique? Are there woods that are more prone to crack?

I've been trying various methods and I've yet to have a rough turned bowl that didn't develop cracks as it dried--black locust, big leaf maple--some of those cracks turned away but it is a constant battle withe the thin CA to keep the cracks minimized. I've tried to keep the bowl walls even and I've been using a waste block on the theory that a thick tenon would create an unevenness that might encourage cracking.

I haven't had access to the best of woods and there may have been micro cracks in the maple to begin with but it's sure been frustrating. It's hard to learn and create a stockpile of slowly drying rough turned blanks...from scratch...at the same time.

DW

In the High Desert of Central Oregon

Re: I just want to ask this...

Barry Irby

>I have not been as "scientific" as I should have been about tracking what percentage cracks and exactly what woods fail worse than others. If I start with sound blanks of really green wood, I think my success with the bag method is near 90%. One of our club members turn the chuck foot off to have a sort of smooth hemisphere on the out side of the bowl before drying, He is sure the chuck foot is the part that usually cracks.

It is best to start with blanks without cracks. Even micro cracks are cracks. If you are working with fond wood, pick up fresh pieces that are several inches longer than the diameter, cut fresh ends and split the blanks. Better to cut the center out to remove the pith and juvenile wood. Turn the blanks promptly and bag them. Or bag them in plastic bags if you can't get to them for a day or two, but they may mold or spalt if you leave them too long.

Try turning some to finish right from green. I turn a lot that way. Try turning one half the blank into a rough bowl blank and the half into a finished bowl. I like to turn them fairly thin, 1/4 to 5/16" and finish them. I like the warping and find it gives them a hand made organic feel. This will keep you busy while the other half drys. I would bet about ninety percent of the drying occurs in the first ten weeks.