Knowledge You Can Build On — Est. 1998
How do you decide...
Ted Owen, Pittsburgh
>whether to:
1. complete a wet-wood hollow object at once, or
2. hollow to twice the final thickness, let it sit a couple months, then complete?
Is it just a matter of deciding whether the final piece should be round or can be warped? Or are there other considerations?
Best, Ted
If any of mine survive I'll let you know
Jay in TX (formerly Ohio)
>So far the handful I've worked on are drying and waiting for their finish turning.
I guess I could finish turn from wet/green stock if warping were acceptable, or if I knew the particular piece of wood was stable. If I had a customer, it would depend on what they wanted and how I could manage it.
Re: How do you decide...
Molly Winton
>For me Ted, it's knowing the wood, and then at what orientation am I hollowing. If I'm hollowing endgrain, and the wood is familiar to me regarding it's stablility I'll turn to finished. If I'm going to put a collar on it I'll wait until it's completely dry and then fit the collar. After drying it most likely will be out of round a bit, but a little sandpaper at the hole will make a collar fit just fine. If the hollow will not have a collar, then I decide whether a little distortion will be obvious and it's aesthetic implications. There really are a lot of "or if's". If it's side grain hollowing, and I don't want any obvious distortion, I'd rough turn, and finish later. You'll have more movement in sidegrain hollowing, than end grain as a rule. All else fails, just experiment if you've got the wood to play with.
Re: How do you decide...
Russ Fairfield
>Ted,
Yes, the wood can warp when it turned to final thickness and rough sanded while it is still wet. The benefit is that the thinner wall of uniform thickness will be less likely to crack, and it will be dry in a few days.
But, the one that you rough turn and leave oversize will also warp, and sometimes you will find that you didn't leave enough wood to make a bowl. And, there is always the higher risk that it will crack.
In either case, you will have to reverse it in the lathe and clean up the chucking recess, or spigot if that is what you used.
Re: Well, Ted, You asked...LONG
Doug Trembath
>You have already gotten some good feedback, but since you asked me for my opinion off-line, here goes...
Depending on:
1. The type of wood - is it relatively stable like walnut / maple, or is it radical like Madrone or apple, or somewhere in between?
2. Desired profile - Is it long and thin, or squat and heavier in shape?
3. Desired grain orientation - As Molly pointed out, this makes a tremendous difference, and will completely negate some options, or make it absolutely doable.
Now, there is no pat answer to your question, unless more of the parameters are supplied. If you want a finished product that appears to be round with very little distortion, rough it out to a wall thickness of approximately 10% of the diameter, or 1" per foot, whichever you choose to follow, coat it with Anchorseal, or bag it adequately, and place it in an area without too much air movement until it is dry, true it up, and return it to a finished piece. If there is any doubt about whether you want a warped turning, err to this side of the argument.
If you want to have a warped turning, simply turn it start to finish, and let it dry. Remember, it can still crack at this point, as well, if the wall is thick enough or if the wall thickness is inconsistant from the rim to the base, or if the darned wood is just too contrary to take the shape you want and hold it. A lot can be done at this point by controlling the drying rate, which can affect the amount of distortion you will achieve.
Any variation is possible, from the highly technical work of Cindy Drozda's fabulous lidded vessels, to the freeform baskets of Christian Burchard. If you use the right materials with the right technique, almost any desired result can be had. Without a pretty good knowledge of the different woods, however, it can be a daunting task to determine which wood/technique to use for which objective. That's where experience and time on the lathe come in. There's simply no silver bullet substitute for that time spent on the lathe, combined with an adventuresome spirit. In other words, try everything you can think of, and see what happens. As I've heard and said before, it's a journey, this woodturning obsession, not a destination.
Doug Trembath
Studio in the Woods
