Hollow Forms - Green wood or dried wood?

[Brian Kent]

Are most of your Hollow Form turnings done with wet wood or dry wood?

Thanks.


Context: Anything I have done in the past is with dry wood. Is it worth a try to do a hollow form with fresh-cut wood?

[Bruce Pratt]

I do mine from green. Just be aware of the usual rules of the road regarding warping during drying. Check out David Ellsworth's hollow forms. Many of them started from green wood.

[Brian Kent]

Bruce, I assume you turn to final thickness, or can you rough turn a hollow form?

[Dennis Ford]

I do both turned to finish while wet and twice turned hollow forms but all start with green wood. Unless you plan to make small hollow forms, don't really have they choice of dry wood anyway.

[Steve Schlumpf]

Brian - all of my hollow forms have been twice turned. Don't have local access to kiln dried HF blanks, so have always turned green wood.

[John Keeton]

Most all of mine are from dry wood. I have only rough turned three and microwaved two of them dry so I could finish turn them that day.

[charlie knighton]

single turn green, just let it finish drying where no drafts will touch it, like in drawer in a chest(tip from JJ)........I like it to be dry before any finish is put on.....usually does not take a week

[robert baccus]

I really resent having to hollow dry wood but have to on most purchased wood. Twice turned is so much more pleasant to work and like Ford says large wood is almost unobtainable. I find it is easier to avoid cracks drying roughed out and waxed wood than large wood.

[John Sincerbeaux]

Hollow green, boil, controlled drying for months, re-turn, sand, pore-fill, spray pre-cat lacquer, rub out, done.

[Bruce Pratt]

turn to final, double or triple bag in brown paper bags, some times with shavings. I'm not patient enough to do twice turned.

[Steve Huffman]

I don't have much experience in turning green hollow's, but while we are on subject, I can share this with you Brian, and others.
The other night I'm turning a hunk of Persimmon (green, green, wet green) to test the Homemade Brute hollower. The form finished roughly 10" tall X 6" wide with a 1.25" opening at top. Before I finished hollowing the bottom, it had developed a small crack in the opening about an inch long. :mad: Panicked, I CA'ed the crack and wet the form with a wash cloth. I had turned this roughly 1/4 inch thickness, and more like 3/16" or thinner near the top opening. I have it triple wrapped in paper, but I don't think I'll like what I see when I open it later on. Maybe it's the nature of the wood, or maybe it should have been roughed out thicker and re-turned thinner later on. Once I had the outside shaped, it took roughly 1.5 hrs on the hollowing at least. If the wood is drying out to quickly, hit it with a spray bottle of water every 15 min????
It was heart breaking to be moving along on a sweet looking project and have it crack before it comes of the lathe.

Please can the experts chime in here on the cracking. Persimmon is a dense fruit wood type.

BTW, the hollower worked fantastic, but will be going to a 1" boring bar before I attempt the deeper hollow forms.

Thanks a bunch!
Steve

[John Sincerbeaux]

Steve,
just my opinion here, I think you went way too thin for it being so wet. On large HF's, I have been taught to turn to an inch to 1 1/4" for the rough turning. Boiling it afterwards will "de-stress" the wood. I then put my HF's in cardboard boxes and let them dry for months. I meter my vessels for MC and wait till <10%. Then, I re-turn to final wall thickness.
You will most likely have to re-turn (re-true) the tenon before you can do your final turning. End grain turnings require less re-turning opposed to face grain which will really go oval. The other critical thing is your final "rough" turning should be uniform.
One last thing, it is very common for there to be some cracks. I wouldn't panic. Deal with them as the vessel dries.

[Peter Blair]

Steve, check out the latest copy of American Woodturner. Great article regarding cracked work and suggestions about how to use cracks to your advantage.

[John Keeton]

On hollowing green, I would form the outside and immediately seal it with a heavy dose of Anchorseal before hollowing. I did that on the couple that I microwaved dry and did not have any cracks. They were not persimmon, however, and while I think the method is sound, it may not be as effective on persimmon.

[Edward Weingarden]

I've been doing HFs for about six months with a home grown articulating arm set up. All of my pieces thus far have been turned green. After shaping the outside, unless it is sloppy wet, I sand with wet/dry sandpaper. I hollow to finished wall thickness of about 3/16". I let it dry off the lathe for about two weeks, leaving the tenon on. That way I can remount and do my finishing on the lathe. If it's a face grain piece, I may get checking at the pith, but that becomes part of art of the piece. The only time I had a crack on an end grain piece (thus far) is when the bar/cutter was six inches in and I had a catch. The bar whacked against the opening, resulting in the crack. I used CA and saw dust to secure it, but I can't say that it looks like part of the art.

[Josh Bowman]

I like doing HF's and have only done them green. I turn the outside and if not able to hollow it then, I wrap mine in saran wrap. Then hollow it with in a few days (I have made it a week or more). I generally hollow on the thin side 1/4" or so. The early ones I did I made them real thin and had no ill effects from the wood moving or otherwise since they, for the most part were "spun" dry. On my later ones that I've done a 1/4" or more, I sand smooth, wrap the outside with saran wrap as before and put it in a cardboard box to dry out for a few days to a couple of weeks. I had one HF open a crack at the shoulder below the neck and a friend said wet the cracked area a little over a few days and I found the crack closed and stayed that way.

[Reed Gray]

Well, the answer is yes... I do some larger containers some times, and since they are going to be fitted with a lid, I have to rough turn them, then turn again. Considering that the lid and body are from the same piece, they seasonal movement should be pretty much the same, and if you spin the lid, it will be tight on 1/4, then loose on the next 1/4, and repeat. If I am turning really green, I use the stretch plastic film on the outside, and at least seal the bottom end grain. I have lost more to cracks if I don't seal it, even if it is covered with plastic. With vases, I go both ways. Any time I am turning Madrone, I want as much warping and wrinkling as I can get. So, I finish turn the outside, and then wet sand, and seal/finish, then turn out the inside. The 3D surface is huge for people who like to pick them up and fondle. Other woods, it kind of depends. I do leave a tenon on, and have to turn it off later. For reasons I don't understand, on end grain green turnings, the bottom seems to warp out, or go convex every time, and never concave. If I finish turn the bottom, the piece never sits flat. While this had never bothered my sales of my warped bowls, it just isn't good for a vase to be wobbly.

robo hippy

[robert baccus]

Don,t feel badly. Persimmon is one of the very most moving, warping wood made. Madrone may be worse. Like Keeton I roughout and wax right then. You can hollow at your convience and not wax the interior. Dries faster and does not move. or crack(?) Many hours faster and easier than cooking.

[Steve Huffman]

On hollowing green, I would form the outside and immediately seal it with a heavy dose of Anchorseal before hollowing. I did that on the couple that I microwaved dry and did not have any cracks. They were not persimmon, however, and while I think the method is sound, it may not be as effective on persimmon.


Don,t feel badly. Persimmon is one of the very most moving, warping wood made. Madrone may be worse. Like Keeton I roughout and wax right then. You can hollow at your convience and not wax the interior. Dries faster and does not move. or crack(?) Many hours faster and easier than cooking.

So in these cases with Anchorseal, do you leave the wall slightly thicker and return them to the lathe? I'm just a bit paranoid about shooting lacquer over any wax and getting "fisheyes". Maybe if the form is slightly larger outside you can cut a 1/8 off to remove the wax, or some kind of wash, DNA? How do you remove the Anchorseal?

[Dennis Ford]

I only put Anchorseal on pieces that will be re-turned and cut the Anchorseal off during the second turning. With once turned hollow forms, I expect warping and make it part of the design.

[John Keeton]

Steve, as with any rough out, I leave extra material/thickness, so as Dennis said the Anchorseal gets turned away.

[robert baccus]

Roger that!