Cracking up... my roughed bowls, that is

[Fred Oliver]

After rough turning some cherry bowls, I put them in paper bags to slow the drying. Too many have developed large (wide) cracks from the rim into the bottom.

They're 10-14" in diameter, 3-5" in height, and I've left the walls and bottoms about 1"-1.25" thick. The wall thickness is fairly uniform. If the bottom was thicker than the walls would that contibute to the walls cracking?

The tree was cut about 6 months ago (October), and I sealed the ends about 3-4 weeks after that. The remaining seven four-foot logs on my covered deck show no end grain checking.

Someone told me this was "wild black cherry" and is notorious for cracking, but very few of the smaller bowls have had problems with cracks. I had some surface checking on the initial bowls - 5-8" diameter - probably because I was sanding at too high RPM.

The smaller bowls, turned green, have elongated but haven't split. The through-and-through cracks are mainly on the larger roughed-out bowls.

Would it be worthwhile to fill the cracks with sawdust and CA, or is that asking for trouble down the road?

It seems a wasteful shame to lose several large bowls - for which I had high hopes. Should I be doing something different, or should I say, "C'est la vie"?

[Matt Hutchinson]

I am not so sure the bowls cracked just because the wood might be prone to checking. You touched on one of the possible problems: wall thickness. It is best to taper the wall thickness. If the rim is 1.25", then it should gradually get thinner towards the bottom, where 3/4" is plenty. If the bottom is thick, it impedes the movement, causing more tension that results in cracks. Also, I am not sure using paper bags to slow the drying process is the best drying method. Yes, it can work, but I prefer to seal the endgrain with green wood sealer. But whatever drying process you use, definitely taper the wall thickness.

Hutch

[Dan Oliphant]

Fred,
The pieces are absolutely recoverable!!! the cracks can be filled with many different possibilities, brass, turquoise (or any other stone you like), coffee grounds, the possibilities are limitless.
In your post, there was no mention of DNA soaking after rough out of the green wood. I would recommend this in the future, the process does displace water from the wood. Thus reducing the cracking problem. Duration is dependent on moisture content, so the soak times will very. My option is to soak for at least 5 days, others soak for as little as 24 hours.

[Bernie Weishapl]

Fred I agree with Dan. I use the DNA soak and with fruit wood most generally for 2 to 4 days of totally covered soak. I then wrap them in brown paper grocery sack like a Christmas present and cut a opening in the bowl side. I put them upside down on a cheap Wal-Mart cooling rack to dry which is about 3 weeks. I very seldom have problems with cherry cracking. I have two drying now with no cracks. Also I leave my bowls with the walls about 1/2" to 3/4" thick walls. If they do crack I use epoxy mixed with sanding dust or coffee ground to fill the crack. Have had very good luck doing that.

[Richard Madison]

Fred,
You don't say if you are turning end grain or face grain, and if the latter how much of the pith you are removing?

As mentioned, can attempt to save cracked pieces with epoxy and additives. Can dilute "fast" epoxy w/ DNA so it will flow into the smaller (not hairline) cracks.

Great score on the cherry if it can be saved!

[robert hainstock]

My expierance is that some blanks just crack. It has to be some sort of stress release. Maybe the sunny side of the tree. You alredy have the various repair methods listed, and I use most of them depending on the crack. Good luck!
Bob

[Dick Strauss]

Fred,
FYI...3-4 weeks is way too long to wait before sealing your wood, especially with cherry. You should seal the would ASAP.

[Chip Sutherland]

I don't wait 3-4 weeks to seal the ends of green wood....unless I want to lose 50% of it. I seal it ASAP. I also use the DNA method but I'm impatient. I'll let the wood set for a few hours after the DNA bath then usually seal the rings where expansion is likely. The only loss I have is a piece of walnut that I didn't seal after the bath. It cracked so I used used some tourquoise inlace and sold last year cheaper than I should have.

[Fred Oliver]

was the delay in getting them sealed. I learned that lesson by "losing" several very nice pieces of walnut root 8-12" diameter x 3' long. (Stood them on my garage floor, went out of town, and didn't 'get around' to sealing them for several weeks.) Most developed radial checks the full length of the log and extending almost to the pith! Beautiful figure, too.

These cherry logs were sealed as soon as I got them, but that was 3-4 weeks after the tree was cut down.

I've repaired the cracks with sawdust and CA, so I'll know in a few months how things turn out.

I think you're right, Matt. The worst cracks seem to be where the bottom of the bowl is too thick. In future rough turning I'll make the bottom a little thinner than the sides, and taper down the side thickness.

I know there are several threads about the DNA soaking, (and I assume that's denatured alcohol) but it sounds kinda expensive, particularly given how fast the stuff evaporates and the price per gallon of denatured alcohol at the local Lowes store.

Is there something I'm missing here? And what kind of container do you use for a 6x14" bowl?

Thanks,

Fred

[William Bachtel]

Cut all the pith out. Cut off as much sapwood as possible, sapwood carries most of the water in the wood. Seal ASAP and seal the entire ruff bowl blank. One more thing listen to these guys on here most know whats best.

[curtis rosche]

just get a bucket with a lid, i use a bucket that was once a chlorine bucket from a neighbors pool, then i put my things in a big ziplock with alcohol, through theem in the bucket, then you only need 1 gallon and you can cover the whole surface, the bucket with lid helps evaporation to stop, it also help incase of leak

[Dean Matthews]

I have done the dishwashing liquid trick multiple times and it has worked out very well for me.

50% water and 50% dishwashing liquid. Submerge the bowl... leave it there for about 24-48 hours in the liquid.

Take it out and wrap it up in some news paper. I replaced the newspaper 1-2 times/week for three weeks and it was pretty dry by then.

Works like a charm.