Turning a deep segmented cannister

[Roger Feeley]

I would like to turn a cannister that will be about 6" in diameter and about 8" deep. It seems to me that doing a segmented turning will not only make it more interesting but easier to turn since I am effectively eliminating end grain.

I have two questions:
1. How should I handle wood movement in the bottom? Surely, I don't just stick a flat piece of wood down there. Won't it expand and split the whole thing? This will be for a powder (Slim Fast) so I don't want it to leak. I would think that a floating panel is out of the question.

2. Should I glue up all the segmented layers at once, do it in sections or one at a time?

[Roger Chandler]

make a floating bottom..........you need room for the bottom to expand and contract..........on your first ring [bottom] cut a dado in the pieces for the ring and fit them around the solid piece of wood.....perhaps a planned down piece of stable species.........do not glue the bottom to the ring segments, just allow it to float........shape to your form, remembering how much wood you have to work with.

[charlie knighton]

Malcolm------you out there someplace

[Ryan Baker]

A floating bottom is definitely important for keeping it together, but I'm not sure it would be enough to completely seal loose powder. If you can work some type of liner into your design, that would probably work a lot better.

[Michelle Rich]

A 6" bottom may not be an issue. Use a stable wood. I have used solid wood to 9" and have had no issues. It may work or not depending on your area, and the humidity variations. If you don't mind plywood, use that, it won't expand & contract. Glue up a few rows, then hollow..glue up a few more, and hollow again. You don't have to worry about long depths this way without having tools for deep hollowing. Good luck

[Bill Bulloch]

I think you should be safe with a six inch diameter bottom if the piece is to stay in one area. The smaller the bottom pieces the less movement there will be. Six inches is probably boarderline , but I live in Georgia where it is very humid and have never had a problem with movement. If I sent a pieces to Arizona, [or vice versa], then that would be a different story. To be even safer use a quarter sawn piece of wood for the bottom piece; quarter sawn wood does not move as much.

Be sure and post a picture of your piece when you finish it.

[Thom Sturgill]

If you are worried about expansion, check the expansion rates for the species you are using, some move much more than others.
A canister is kept indoors, in a relatively humidity controlled environment (espicially if you have A/c), then movement is minimal.
You can also use a floating ring and glue it in with epoxy or silicon sealant which will remain flexible, just make sure it is food safe.

[Jim Kountz]

Or, you could just make a laminated or segmented bottom thus reducing the chance of movement.

[Paul Engle]

Some years back I did one about the size of a gallon glass jar. I used a piece of oak well dried for the base and then 12 , 16 segment rings for the jar from Mahoghany , purple heart for the lid trimed in maple with large claro walnut knob ( for her arthritus ) and food grade O ring to seal the lid. I coated the inside with thinned epoxy applied to the inside ( 20 minute stuff thined with acetone ) while turning very slow and let cure while turining for about 2 hours to get a good set. The jar has been banged and gotten wet a few time and still solid as the Mrs. uses it for flour . The mouth opening is about 5 inches . Got blue ribbon at the county fair that year 2009 I think . I glued up all the rings and let set for a couple of hours and then turned the whole thing at one time. I put a section in the middle that had purple heart and maple accent and left a space for a tag that I was going to have ingraved but so far have not got that part done . Since the out side is finished with wipe on poly and the inside is coated with the epoxy , I have not had any movement , but the kitchen is stable temp but the humidity goes up and down but has not effected it at all . I can get some fotos if you like and post but I think the archive has some that I posted when it was done .

[Roger Feeley]

Thanks to everyone for the great advice. I get two general impressions about my original question.
1. Don't sweat it too much. Several posters have turned fairly large pieces and not had problems.
2. If I do want to do something, I could make the bottom segmented as well which would turn the movement 90 degrees and eliminate the problem.

Of course there was no shortage of other good advice too.
One poster suggested that I minimize the problem by reducing the effective size of the bottom. I could do that by making the bottom ring a bit thicker (the inside diameter smaller).

I'm leaning towards the segmented bottom glued into a fairly deep dado with epoxy.
I'm leaning towards making the bottom ring thicker so that I will have a stronger section to mount on the chuck.

this will be good practice for a project for Christmas 2014. In that one, I want to make a segmented vessel with 9 segments. 8 will alternate between cherry and maple. the ninth segment will be walnut or ebony. There will be 10 rings. the bottom and top will be walnut or ebony. the result will be a rolled up checkerboard.

Thennn.... the idea is to embed a magnet into each segment before turning so that you can play checkers 'in the round'. I will mount the thing on a lazy Susan. I will give them this 'vase' and a bunch of turned checkers.

[Robert McGowen]

[QUOTE=Roger Feeley;2194259]
I'm leaning towards the segmented bottom glued into a fairly deep dado with epoxy.
QUOTE]

I am not exactly sure what you mean, but am guessing you are planning on making a segmented disc that resembles a pie for the bottom. Of all of the choices given, this would have to be the worst choice of them all. You are almost guaranteeing that it will come apart.