Once Turned Cherry Bowl

[David Delo]

After receiving positive comments yesterday about some recent work, I decided to slice a chunk off of 1 of the 7 ten inch cherry logs I got right before getting sidelined 7 months ago. This particular log was the one in the worst condition crack wise but salvaged a nice piece I thought would give me about a solid 9" bowl. Log check in at 19% moisture.

Had every intention on making a twice turned bowl but by the time I got rid of all the bark I realized it was going to be smaller because the log was more of an oval shape than a circle. Finished up the tenon and turned it around and began hogging out the inside. I've never done a wet wood once turned bowl, always twice turned but while I'm doing the inside and seeing it's not going to be that big of a bowl, decide to just finish it off as a once turned piece.

After getting the inside done and machined down to a heavy 1/8", I find the piece has gone out of round by a quarter inch. Since I didn't sand the outside while still having wood on the inside, made sanding the piece a real challenge. That's why Bob B. I say sometimes I get a birdie and other times I'm hitting out of the sand trap all day. Had a couple tool marks and a little bit of torn grain that gave me fits trying to get rid of. Sanded the piece on and off the lathe and finished it off with a coat of walnut oil.

So, what's the proper way to do these in one turning? Sand the outside before before turning around? I think my tool marks on the inside come from being a bit too heavy handed with too big a tool. Was using a 5/8" bowl gouge because I originally was just going to twice turn and leave 3/4" or so wall thickness. Probably should have switched over to 1/2". Any sequence help, greatly appreciated.
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[Russell Neyman]

I'd say you've done it "the proper way," David. I assume this is fairly fresh wood, although the cracks tell me that the tree wasn't taken down last week. It all depends on what you're after. An irregular, bean-shaped bowl is what you can expect from freshly cut fruit trees. Some people absolutely love the texture and asymmetrical shape, while others consider it ruined. It think this is a matter of right-brain/left-brain stuff.

If you'd like less out-of-round, I can offer a few insights. My favorite green wood is madrone, which is pretty darn warpy and holds a high amount of moisture. I turn it wet and very thin to a form similar to what you have pictured here. Sometimes I like the dried results and sometimes I don't. So, three experiences:

>> Use a form to control the side-to-side distortion. This can be nothing more that a piece of plywood with a hole, cut to the size of the bowl's rim, that is placed around the piece. It's a good idea to pad the wood with a cloth or paper towel to keep from marring the surface. You'll also need to secure it in some way, with a weight on top, perhaps, to keep it from popping out of the form.

>> Place green pieces under pressure, between two pieces of plywood to limit the up-and-down movement. Obviously, this can be used in conjunction with the first suggestion.

>> For a piece that is already dried and, presumably, has an unpleasing warp, try steaming it and then using any the above ideas. I've done this often with good results.

There are some risks to picking a fight with a bowl's desire to change shape. First, areas that are under the suggested forms may color differently. Also, you may encounter cracking in areas where the tree simply needs to move and is in conflict with the shaping process. A key to minimizing this is to make your green-turned bowl's wall at a consistent thickness, including any mounting tenon. Take that off if at all possible. Obviously, check the status often to see if any fissures have developed.

[Barry McFadden]

David....I usually turn dry wood but sometimes I get a wet piece of Spalted Birch or Maple when I'm out walking the dog. When I turn a wet piece I turn the outside and then sand it to 120 grit and then turn the inside to the thickness I want and sand it to 120 as well. I weigh it then put the piece in the microwave for 4 minutes at 40% power. I check it see if it's hot... mostly at this stage it's just warm and put it in for another 4 minutes. I let it cool and weigh it again. I continue with this process until it isn't really losing much weight and by that time it's pretty much dry. The bowl will warp some but I've never had one crack. I think the warp adds to the appeal of the spalted piece. I then put it back on the lathe and sand down to the final grit and finish it. Here's a couple of Apple bowls I did this way......

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[David Delo]

Thanks for the advice Russ & Barry. Good food for thought.

[Mike Goetzke]

David -glad to here you are back at the lathe again. That cherry bowl looks great - keep us up to date on how it changes while drying.

Also, I need to build a cutting station, can you give some details about yours?


Thanks,

Mike

[John Keeton]

David, I think your "tool marks" may be heel bruising. That could be related to a large gouge, but either way there are a couple of things that may help if the marks are, in fact, bruising. Using a higher angle on the gouge as in a "bottom feeder" and grinding off a large portion of the heel of the gouge. I remove the heel on all my gouges leaving a "working bevel" of only about 1/8" or so.

From what I see, the form looks very nice and a really nice piece of wood. Good thickness, as well.

[Bob Bergstrom]

I have been turning a lot of natural edge once turned bowls lately. Warping on a natural edge bowl doesn't distract from a visual aspect. After cutting the out side with a 40/40 grind, I will use Titebond thin super glue on the rim and candium layer. Titebond is thinner than Stickfast and sets quickly. With the outside cut cleanly I will reverse the bowl and use that 40/40 grind to cut the inside below the wings. Putting the tool rest as close as possible to the wing area will give additional support to the gouge. At this time I will soak the inside of the rim with thin super glue. This will usually keep all the bark on during drying. The 40/40 grind will cut the wings cleanly with a minimum amount of tool marks. Many turners, using a shorter bevel, have a tendency to push the bevel into the wall causing ripples in the wood. The 40/40 cuts toward the headstock while the bevel floats over the wood. After cutting the wings, I switch to a steeper grind with the heal of the bevel ground away. I will cut toward the bottom. A freshly ground tool with light pressure will minimize tear out. Once the bottom is shaped I use a steep ground gouge with the wings on it (bottom feeder) to slice a finish cut. When cleanly cut, I flip the bowl and mount it on a vacuum chuck to finish the foot on the bottom. I will cut the recess in the bottom a little deeper so I can sand the foot after drying. After 3 weeks it is dry and I mount it on the vacuum chuck and sand the outside. Next I'll do the same to the inside. All sanding is done with a close quarters drill while rotating the bowl by hand.

[daryl moses]

I like this bowl a lot, tool marks or not. It will make a great "user" bowl.
When I first started turning, all my bowls were finish turned [green wood] all at one time. Sometimes they would warp symmetrically [that's an oxymoron] in other words the warping would look almost as if it was intentional. But others would warp unevenly and I never liked the looks of them. Although some people like the uneven warped look.
I hope this bowl will "behave" and warp evenly for you.

[David Delo]

David -glad to here you are back at the lathe again. That cherry bowl looks great - keep us up to date on how it changes while drying.

Also, I need to build a cutting station, can you give some details about yours?


Thanks,

Mike

Mike,

Plans copied from a guy in MN. Has pictorial on the chapter website www.mnwoodturners.com Click on December 2012 newsletter.

[David Delo]

John K, Bob B, & Daryl,

Excellent advice taken an absorbed. I think some of the difficulty was from switching my plan from twice turned to once turned in the middle of the process and then trying to rush a bit to avoid having to deal with the piece warping. Should have just stuck with plan A.

John, I did use a D-way 5/8" gouge that I recently changed changed from 45 degrees to 60 degrees for this piece. I do have the heel ground down but don't think down to 1/8" cutting. I'll have to check when I get back home later this week.

Bob, I do use bottom feeders quite a bit ground at 75degrees + heel taken off on the Hippy platform. Like results a lot but on this bowl I got nice results from just the 60 degree on the D-way. At the time, I didn't even think about using it further up the bowl rim. I do use the 40/40 almost exclusively for shaping tenons with a 3/8". Get good results on the outside almost all the time but haven't mastered those results for the inside of the shape.

All that said......I do prefer a circle for a bowl over the oblong style but have enough stock to practice a few of this style and will try to incorporate yinz's comments accordingly.