Possible to leave pith?

[Steve Mathews]

I always made sure to eliminate the pith in any of my turnings usually at the expense of wasting wood. But lately I've noticed some on YouTube incorporating that into their work. I just attempted to make a box from a walnut branch, which left the pith at both the bottom and top. Of course the pith had severe cracks but they were filled with epoxy and seemed to look fine. Is this approach OK or just foolish?

[Chris A Lawrence]

I have made 3 large hollow forms using this technique (http://keithlarrett.com/2013/07/26/turning-hollow-forms-pith-to-pith/) with 2 successful and the other one just starting the drying process. Both times it worked as planned with the waste block cracking but the crack not transferring to the form.

[John K Jordan]

I always made sure to eliminate the pith in any of my turnings usually at the expense of wasting wood. But lately I've noticed some on YouTube incorporating that into their work. I just attempted to make a box from a walnut branch, which left the pith at both the bottom and top. Of course the pith had severe cracks but they were filled with epoxy and seemed to look fine. Is this approach OK or just foolish?

Many people use this method. Some even cut out the pith in the bottom and glue in a plug. Some pros who make hollow forms with very tiny openings use this method to hollow.

JKJ

[Steve Mathews]

Wow! This opens up some interesting possibilities and new uses for the scarce wood we have here. I wanted to use a glued plug but thought it was bad form. Now I'm thinking of using one of my larger walnut logs for a larger hollow form and gluing an entire base to it of contrasting wood. The glue up might be tricky though.

[Dennis Ford]

I have transitioned from avoiding the pith completely to occasionally including the pith (some with pith in the bottom and some hollow forms with pith in the side). Pith in the side of hollow forms has worked pretty well for me when the piece is turned thin enough to warp even with difficult woods like dogwood. Pith in the bottom of hollow forms has proved more difficult to master for me (requires careful drying).

[Edward Weingarden]

I turn many of my hollow forms (most of them end grain) with the pith in, with a good success rate for non-cracking. When I turn in one session to a finished form, I try and make sure that the drying process is done very slowly over a couple of weeks. When I do twice turned pieces I coat all of the exterior surface, including the waste block, with anchorseal before proceeding with drying over many months.

[Robert Hayward]

I like turning bowls, lidded boxes and so on with the pith in them. I fill the cracks with CA and sawdust, epoxy or what have you. A little over a year ago the edge of a hurricane gave us a pretty good blow here in the Tampa Bay area. A neighbors dying loguat tree blew over and I grabbed the trunk wood and squared it up on the bandsaw. It was a smallish tree so I left the pith in the pieces thinking they would make nice lidded boxes from an unusual wood. Coated the ends and put the pieces up high on a shelf in the barn where wood dries slowly and almost never cracks. Six months or so later pulled them off the shelf to see how they were doing. :(

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[John K Jordan]

And perhaps make a contrasting base and rim of the same contrasting (or complementary) wood for visual balance.

As for hollowing, Mark Gardner shapes the outside, cuts the piece in half somewhere in the middle, hollows each half, turns an tenon and recess to rejoin, then glues the piece back together. He often carves, textures, and colors which makes the join invisible.

JKJ

[Richard Coers]

To get a good fit on the lid, you need stable wood. Wood around the pith moves a lot and will likely go oval. That makes a lid that may fit poorly and will certainly require proper orientation to fit at all.

[Mike Nathal]

To get a good fit on the lid, you need stable wood. Wood around the pith moves a lot and will likely go oval. That makes a lid that may fit poorly and will certainly require proper orientation to fit at all.

I believe if you center your piece around the pith it will shrink symmetrically and stay circular. If the pith is not centered, then you can get ovals. And end grain boxes are less oval than side grain.

[john taliaferro]

If you fit a plug don't fit tell dried as it will not shrink at the same rate and will crack .

[John Sincerbeaux]

I only turn Hollow Forms and I only turn face grain. I think the pith and grain/figure associated with the pith yields a much more interesting vessel. Definitely adds more challenges, but think it is worth it.

[robert baccus]

I've turned many bowls and vases twice turned with mostly sucesses. Cure between turnings with care--use a lotta end sealer and time.

[Leo Van Der Loo]

Steve, like Robert above here says, turn green wood without splits and dry it carefully, I’ve always done it that way, and have no problems with it working that way.

However I you feel the box is stable and won’t move anymore, than you could do as I have with these boxes (they had no splits) for a more interesting look than split wood has.

Bone, spalted Oak and figured Maple are here used to add to the overall look.

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[Dan Bevilacqua]

Leo, those are beautiful boxes. Would you mind telling me the respective dimensions?

[Jon McElwain]

My wife and I were visiting the Empress Hotel in Victoria, British Columbia a few years back. We stopped in one of their fancy galleries during the course of our outings, and I was admiring some of their wooden vases. I was looking at one vase in particular (probably 24" tall and 18" dia.), noting that it was turned with the pith running vertically through the center. The curator came over and started giving me some line about how I deserved to treat myself to the vase, how I may never have another chance to buy it, and I should just go for it. The price tag was $9,000 - like I had an extra $9k to drop on a piece that I could make at home from a piece of firewood. So, I told her that it was cracked on the bottom. She was put off and seemed offended (I could hear her thinking, "we would never sell something that was cracked"), but when I told her to check it out, she grabbed her white gloves and tipped the vase over to look. Sure enough, 3-4 cracks, one about 2" long, were running out from the pith. When she asked me how I knew it was cracked, I just smiled and walked out. I'm sure they went back through the security footage as soon as I left...


I've turned a number of bowls, vessels, and hollow forms with the pith in them. The big thing is that you have to expect and plan for some cracking and warping. I've been able to avoid cracking some of the time, but I've never completely avoided warping. I probably could if I was more patient with waiting for it to dry, or if I used the twice-turned method. But is seems like no matter how long I dry the wood, when it gets down to the last few cuts, it releases just enough moisture to warp a little.

19" Bowl with the pith just beyond the rim:
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Same bowl a few hours later. Not a great picture, but you can see just a little warp on the edge at the center of the heartwood, but no cracks:
397516
The two little pots have pith running parallel to the ground. They both warped and are now a little oval shaped, but since they were turned fairly thin, they didn't crack. The light colored one has the pith running vertically. It did crack on the bottom, but not on the inside. There was also some warp to the foot, but I was able to sand it back flat. Again, not the best photo:
397517

Moral of the story: if some lady can sell a vase for $9k with a crack in it, I think it is worth it. My experience leads me to believe that with a little planning and care, the pith can add a lot of character and give you access to larger pieces if you are so inclined to turn them!

[John Sincerbeaux]

Kudos to the woodturner who has a piece in a high-end gallery. Secondly, who has a price point at $9k.

Back to the thread.... I view my vessels as a race from the start. Everything I do gets twice turned, boiled, and slowly dried for at least a year. When, I turn to final thickness, I dont get any further movement because it is dry dry dry.

Below, I wrap the outside to prevent rapid moisture loss to the surface. It stays wrapped through the hollowing process till I boil it.
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