Your pinions on how to prevent cracking please

[Rob Holcomb]

I have 2 Cherry bowls roughed out and currently in DNA. I know Cherry will crack more often than other types of wood but the last 4 bowls I've roughed out have cracked at the rim. When I take bowls out of the DNA after a day or two, I wrap them in newspaper. Usually 3 layers. I leave the inside of the bowl exposed with the rim remaining wrapped and place them upside down to dry in my house where there isn't too much disturbance or air movement. Bowls I've turned out of white oak, maple and ash have dried without cracking and I've been able to finish turn them. The Cherry has been a nightmare. Only 1 bowl has made it through the drying process to date. Do any of you have any techniques that I can try with the 2 bowls I'll be removing from the DNA in the next day or two? Thank you in advance!

[Brodie Brickey]

It sounds like the rim is drying out before the rest. I will assume that this is not end grain turning...

I don't use the DNA process, but in the turn wet and bag process, the most important thing is to have a consistent thickness. With the bowls being that nice size (not too large, not too small), I'd put a bowl in the paper bag and seal it closed. No shavings or anything else inside but the bowl. Let the bag transfer the moisture out slowly.

The other alternative would be to coat the rim in 'Anchor Seal' or a similar product and follow your current process. This should slow the drying process around the rim while maintaining the normal process for the rest of the bowl.

[Cathy Schaewe]

I had absolutely no luck using DNA on cherry. On the other hand, I have half a dozen cherry forms roughed out a couple of months ago to about an inch thick, and sealed with anchorseal. Some of them I just sealed the outside, some of them the whole thing. They're on my basement floor, open side down. None of them have cracked to date .... wish me luck!

[Dan Forman]

Never turned cherry, but make sure the edges of the bowl are rounded, not sharp, both inside and outside edge.

Dan

[Steve Vaughan]

I've rough-turned a number of cherry bowls and never had any problems. I'm soaking in dna and then put them into a paper grocery bag. Around the bowl and inside the bowl, I pack it with the shavings, seal the bag up for a month or two, then check on it's progress, removed the shavings and put it back in the bag for another while.

[Sean Hughto]

I don't find cherry to be a particular cracking problem. Apple can be challenging, but cherry has treated me well for the most part. After a year of turning, and dozens of bowls, I'm finding that cracking is largely a function of how wet something is and how large. The bigger the circle and the wetter the starting point, the more drastic the movement and bigger the challenge. If the cherry is from a log that had a chance to dry a bit, either in the forest, or after being cut, it seems to help a lot. I have the most cracking when I'm turning something so green that watter is streaming off the piece as I work it - stuff that is just a bit clammy or that produces a dampish pile of shavings is usually much more forgiving as long as there is not some wierd grain or other weak spot.

[David E Keller]

I agree with the suggestions for even thickness and rounding over the edges. Obviously, any trace of the pith needs to be removed from the bowl before soaking.

Beyond that, you're looking for some way to slow down drying at the rim. I think some people have suggested using cling wrap or packing wrap on the rim although I haven't tried it myself. The anchor seal should work, too, but I'm not sure how well it works after a DNA bath.

Keep us posted if you find a sure-fire solution.

[Bill Buchanan IN]

I have found no need to wait days before wrapping DNA soaked cherry rough-outs in newspaper. I allow excess DNA to drip off back in to the tub, then a flash dry for an hour or two at the most. I have to wonder if your cherry roughs start to crack while the DNA dries in those few days before wrapping in paper. The only time I've had serious cracks is when I got distracted and didn't wrap them quick enough.

[Bernie Weishapl]

I used to use the DNA method but have started using Mike Mahoney's method which is turning the blank to 10% and sealing the whole bowl with anchorseal. I store them in a cool place with not much air movement and on the floor. Make sure as was said earlier to round over the rim edges both inside and outside.

[Reed Gray]

Rule of thumb, if it cracks, it is drying too fast, and if it is molding, it is drying too slow, but that isn't always a bad thing. I am one who uses the plastic wrap on the rim of my bowls. I do turn to final thickness (1/4 to 3/8 inch thick), round over the rims, stretch the plastic film a couple of times around the rim (about 1 inch inside the bowl, and the rest on the outside. The paper bag (single, double or even triple) would not work well with Madrone, which is the most difficult wood to dry I have run across. The plastic stretch film made success rate almost 100%. Even in pieces with knots in them.

robo hippy

[Kyle Iwamoto]

Did you get rid of the pith? I don't think anyone has mentioned it. AFAIK the pith creates 90% of the cracks, so you need to get rid of it. I apologize if you already knew that.
There have been so many different "ways to keep bowls from cracking" discussions here. It depends on where you live, how you store your bowls, how thick you rough turn. What works for you may not work for anyone else. I think the best and most expensive way is to coat the entire bowl with Anchorseal. The problem with this is it will take well over a year for the bowl to dry. I use the paper bag and shavings technique and it seems to work most times for me. I still get some cracks. A friend just stores them in a closed cabinet. No light, no air movement. Try the different ways and find what works for you......

[Wally Dickerman]

Cracking is a problem with most any wet wood if not treated right. I seldom turn wet wood to finish. I rough turn and re-turn when the rough outs are dry. I very heavily coat the rough tuned pieces with Johnson's paste wax. I very seldom experience cracking with this method. I live in hot dry Arizona and the pieces are stored in a sometimes very warm shop. I've been using the wax method for perhaps 40 years with great success.

With woods that are very prone to cracking such as fruit woods, I also store them in a brown paper bag for a few weeks.

Right now I have at least 60 rough outs in my shop. None are cracked.

I buy Johnson's wax in cases of 6 cans direct from the mfr.

Wally

[Rob Holcomb]

Thank you to all who shared their opinions. I think some of you misunderstood me though. I don't wait days to wrap my bowls after soaking in DNA. I soak them for a day or two and then wrap them within an hour of removing them from the DNA. I think I'm going to try the paste wax on the rim with the two bowls that are currently soaking and see how they come out. Thanks again for your contributions!

[Mark Levitski]

Wow, as usual a lot of different comments. Can be confusing until you sort things out for yourself. This forum and ALL advice is invaluable, but experience is the greatest teacher. Try different things and find out what works for you.

I have had good results with just the paper bag in my shop at 40%RH and not much air movement. Yes, cherry too. My biggest revelation was to make sure that you are not starting with any cracks in your blank--even small ones. In certain species this is more forgiving, but in others a sure waste of time to turn and bag. This has been the one greatest help in preventing cracking for me. Know the blank you start with. If a log, I cut off at least a foot before even trying to turn if it has beeen sitting (and checking) for any time. Sometimes even if end sealer was used this will need to be done. I just threw out two out of four of 14" hard maple salad bowls that I roughed out for a custom order for a set. I fudged on the "cut off the first foot" rule and sure enough those are the bowls that cracked. One foot up the log, absolutely none.

I have said this before--sealing the whole thiing with Anchorseal will be slo-mo drying to the point of cutting open almost green wood after 6 months on the shelf. At least for me. Too slow for roughouts but good for long-term preservation or for those with more patience and time than I. Use the sealer for endgrain, knots, and other gnarly portions. Try to, as others have said, even out the drying and slow it, not stop it entirely.

A little mold or mildew is not a problem and way better than open fissures in your wood.

I have never had any problems with sharp edges in my roughouts, across the different local hardwood species (WI) that I work with. Lucky? Maybe, but there are many different experiences as well as myths and wives' tales in all pursuits and endeavors. Use your own experience to sort it all out. For that, keep turning.......

If your pieces have the pith or very near it at the rim, then it will be all the more vulnerable. Yes, the pith is very prone to cracking. However, to carry a blanket policy of removing all piths is to disallow some mice features. Even some cracks can add to the character. One need only look at some of the established and professional turners and their "cracks". You can see some examples in some elite galleries. Turn some piths, let them crack, and learn. Then turn some more. Get a woodstove for the inevitable 10-15% that fail, if one turns any large amount of pieces, even with all the advice of the turner/sages and meticulous attention to technique. Remember, every knot has a pith. Wanna necessarily exclude the knots?

Piths/no piths and scrapers/gouges might fall into the same category of opinion, huh Reed?

Mark

[robert baccus]

i,ve been playing with cherry for 30 years. great in board form...our southern cherry is "different from northern cherry" every piece tried in my shop has cracked despite every trick known to science. i once cut a live cherry tree down and plainly heard it cracking on the way to the ground! unbelievely durable however..i am an old field forester and woodworker and have watched many "durable" species rot rapidly. i once though spied a funny looking tree several hundred yards distance, walked to it and found a perfectly good-solid cherry tree heart standing nicely. the sap and bark were completely gone. i cut a nice16" dia., 24' log completely cured and cut it into boards the next day. i have seen s.red cedar do the same thing but few other trees.