how to build 20" diameter veneered cylinder

[Lynn Kasdorf]

My coffee table client is at it again. This time she wants a pedestal for a sculpture. She wants a 20" diameter, 30" tall cylinder. The finish is to match the "ebonized" wood used throughout her house. From what I can tell, it is just black...

So- there are a number of challenges as I see.

I figure I would fashion some number of discs from 3/4 ply. I'd have a large dowel running up the middle to keep them aligned. Then, I'd have some sort of spacer blocks between each disc to keep them parallel. Glue the whole thing together.

Then, get some "bending plywood". I've never seen this, but apparently there is a 3 layer plywood that is designed for bending. It might be only 1/4" or maybe 3/8". One concern I have is how to have the seams not straighten out- that is, how do I bend it such that there doesn't end up with a flat spot at the seam.

Also, how do I keep the plywood from wavering in and out at the seam?

Then, assuming I get the substrate put together nicely, I need to wrap veneer around it and have it meet with a perfect seam.

If I could find a piece of plastic sewer drain pipe of the right diameter, it would save me massive amounts of time. Is there such a thing as 20" drain pipe?

If I had a large enough lathe, I could laminate a bunch of beveled strips and then turn it. No 20" swing lathes around here though.

Maybe I could build one- and use a router on a track to carve it down to a cylinder as I rotate it by hand. Hmmm...building such a rig might be easier than building the cylinder as described above.


If I could make it out of solid wood like this, then i wouldn't have to veneer! Well, I'd have to veneer the top, but that's all. Sounding better all the time...

Any ideas here are welcomed!

[David Christopher]

Lynn, you can get sonotubes ( the carboard ones for concrete ) cut plywood for the ends and the veneer the tube.........Ive seen subwoofers made this way

[Lynn Kasdorf]

I was just now thinking of sonotubes- one issue is the spiral seam on the tube- I'd need to prevent that from telegraphing through. Maybe just a layer or two of junk veneer beneath the finish veneer. I have plenty of junk veneer for this purpose.

Thanks for the idea.

[Jamie Buxton]

http://www.aitwood.com sells veneered plywood cylinders. They have the usual cabinet hardwoods -- maple, walnut, mahogany, oak, etc. A cylinder 27 1/2" tall will cost you about $100, depending on species.

[David Christopher]

Lynn, you can put sanding sealer on the tube and sand it and that will get rid of the seams

[Lynn Kasdorf]

http://www.aitwood.com sells veneered plywood cylinders. They have the usual cabinet hardwoods -- maple, walnut, mahogany, oak, etc. A cylinder 27 1/2" tall will cost you about $100, depending on species.

Hey Jamie- you NAILED IT! These are perfect. I can just buy the dang cylinder, then attach top and bottom discs and veneer them. Badda bing.

Thanks for pointing me to these. The price is quite reasonable compared to the effort it will save me.

The only trick I see is this: the seam between the top disc and the cylinder must be perfect. If I buy a pre-veneered cylinder, then I would need to fashion a top disc that would fit perfectly inside the cylinder. I'd then veneer a layer of junk veneer across the top to cover the seam, then a layer of finish veneer crossbanded.

OR- I could buy their paint grade cylinder, and their matching MDF caps, and veneer the cylinder myself. This would have the advantage that I would have the top and sides done in the same veneer so the grain would match after painting black.

Thanks!

[Peter Quinn]

Hey Lynn, we recently used a few of their (aitwood) 1/4 round cylinders for a hood surround and the quality was excellent. We used them inside out as a sort of giant cove molding to top a rectangular frame and panel box and form the transition to the chimney riser. It would have taken a considerable amount of time to form those pieces in the shop. Great time saver. Good luck with the project.

[johnny means]

Then, get some "bending plywood". I've never seen this, but apparently there is a 3 layer plywood that is designed for bending. It might be only 1/4" or maybe 3/8". One concern I have is how to have the seams not straighten out- that is, how do I bend it such that there doesn't end up with a flat spot at the seam.

Also, how do I keep the plywood from wavering in and out at the seam?

Then, assuming I get the substrate put together nicely, I need to wrap veneer around it and have it meet with a perfect seam.

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I work with a lot of bending ply. I would not suggest it for veneering, as it has a ridged surface that runs across your curve. For this type of work I would use bending MDF. Of course the MDF has a perfectly smooth face for veneering.

If you decide to veneer your cylinder, overlap you veneer at the seam when you glue it up. donn't apply glue to the inch or so near the over lap. after your glue sets up, use a straight edge and a razor to cut through both layers of veneer. Apply glue to your perfectly mated seams and it's done.