Maple Bowl with Drying Lesson

[Steve Schlumpf]

This bowl was roughed out in the middle of June this year and was turned thinner than 10%. I thought – if it’s thinner it should dry faster! It did but it also warped different than the norm, which I believe was caused by the uneven distribution of heartwood and sapwood. My experience with drying bowls has been that they will warp into an oval pattern. This bowl warped more into a ‘D’ pattern than an oval and I had serious doubts that there was enough wood left to finish turn the blank. There was – but not by very much. Lesson learned for me - I will turn all my stock to at least 10% from now on and be patient. Better to have to wait for a blank to dry than lose the blank all together because I roughed it out too thin for proper drying!

Maple bowl (with some nice curl) 8 ¼” diameter x 3 ¼” high x a shade over ¼” thick at the rim tapering to 3/8” at the base. Four coats of Minwax Wipe-On Gloss Poly and will buff after the finish cures for a week or so.

94093 94094 94095 94096

As always your comments, critiques and opinions are encouraged!

Thanks for looking!

[Toney Robertson]

Steve,

Nice looking bowl. Good form and good looking wood.

I know what you mean about the 10% thing. I want to turn to finish every time. I want to see the fruits of my labor. I must be ADD.

Toney

[robert hainstock]

I waited thirteen years to finish my urn. Get a littke patiencer,(RIGHT NOW). Nice save Steve. t comes to me that you are getting this bowl turning thing figured out.That is another beauty. :):):)
Bob

[Matt Hutchinson]

Hey, the challenge makes life interesting though, right? Good work!

On the thickness subject, I have found the initial moisture content to be a deciding factor when determining how thick to leave the walls of a rough bowl. A few years ago I got a 23" diameter cherry bowl blank for dirt cheap. The turner I bought it from had a huge cherry tree delivered (four 7' lengths that were 24" in diameter!!!), but it had been down for at least a year, maybe two. The 22" bowl I roughed out of it was only 1.25" at the rim, but that was plenty. I just second turned it a few days ago, and the rim is still over 3/4" thick.

Congrats on the 'moderatorship', and as always, I'm looking forward to what you come up with next! :)

Hutch

[Nathan Hawkes]

Nice work Steve. I've had some hard lessons recently with that 10% rule.:(:(:mad::mad:. I roughed out a bunch one day in a hurry. Dumb move. Oh well. Thanks for sharing this one. Nice maple. Looking forward to your next work.

[Reed Gray]

Steve,
If the bowl isn't centered on the pith, it won't warp into the normal oval shape, and I don't think yours is. If you take a quarter sawn blank, the sap wood will shrink more than the heart wood. Of course, some woods will not conform to normal no matter how they are cut, like Madrone. I have had the end grain part shrink in towards the center, I have had centered pieces turn into triangles, I have had a bowl finish moving at 13 inches long, and 8 inches wide, I have had some warp that much, and be dead flat on top and bottom, I have had 6 inch bowls vary in height by 3 inches. Some times, you just never know.
robo hippy

[Steve Schlumpf]

Thanks everyone for the kind words! I do appreciate it!

Reed - you saw the problem exactly as it is. I cut this blank off center intentionally just to get a different look. Never thought how that would affect the drying process. Was quite the sight when I picked up the rough out and went to finish turn it - had never seen a 'D' warp before! I had serious doubts that there would be enough wood there to finish turn but that was due more to my never viewing a 'D' form before! It worked out but I did sit back and think about why this had warped the way it did and the answer was in the grain. Ended up with about 2/3s of the bowl being heartwood and 1/3 being sapwood. Like you said - not centered on the pith so it will pull in one direction more than 2. No big deal but something I will be a little more aware of when I cut the logs up into blanks!

[Leo Van Der Loo]

Hi Steve, nice bowl again :cool:
Yes we can get surprised when drying wood, and I think it is as much an art as a science, a lot of experience really help here.
I remember when I rough turned a bunch of Smoothbark Hickory bowls, and when dry found that they had shrunk more than the usual, so there I had a bunch of bowls with to thick walls but not enough to return :o :D.
Last night I had to decide on equal sapwood or a centered crotch-feather, as it was an unequal crotch bowl blank, (while not sure that the feather will show much) I decided that an equal looking sapwood bowl would be better than a feather that was centered and the sapwood off and the bowl dry probably all warped.

[Norm Zax]

Steve - what form of sealing did you employ? Was the bowl sealed on specific sides or put into paper wrapping for the duration? I rounded over a bowl the other day and completely covered it with paraffin wax but then decided this would take years to dry. What would be the "safe side" to leave unsealed?

[William Bachtel]

Sometimes, right before re turning a ruff blank, that I suspect is not completely dry, I put it in the Mico wave. Works every time. Summer humidity will not let a blank completely dry at times.

[Steve Schlumpf]

Norm, I've been using the DNA method since last year and as long as I keep the blank a consistant thickness I've had good luck. Once the bowl comes out of the DNA and the surface is allowed to dry a little - wrap the bowl with brown paper bag such that the outside and lip are totally covered but the inside of the bowl is exposed. Then store the bowl with the paper side up on a rack or something that allows the air to move around the bowl. In about a month or so, depending on temp & humidity, you should be able to finish turn the bowl. The idea of wrapping the outside of the bowl only is to allow the inside wood to dry slightly sooner than the outside and causes a an equal compression to happen during the process that 'helps' prevent cracks. Lots of info out there on the DNA drying method - should you want more.

[Ben Gastfriend]

Looks great as always, Steve.