wood tubes - observations and questions

Experimenting with wooden tubes, 16 sided and have both observation and questions.

I used the birds mouth router bits to make up the slates, 16 in all. There was great difficulty in making assembly, not a simple chore. Unlike regular slats cut at the correct angle, and rolled into position, the birds mouth sloted slats need to be put together individually one at a time. Looking at the joints I dont see if there is much difference in strength between regular joined slats and the birdmouthed slats. Of course we are talking about a glue joint here.

The tube I made up is 12" OD and 5 feet long. This was a test for a 12" tube 12 feet long. So right now I am thinking to use the standard angled flat face joints for the big tube.

Any thoughts, answers or comments??

Thanks, kreig

[COLOR="Purple"]Hi Kreig!
The only wooden tubes I've made were MUCH smaller...1/4" plywood glued up to make a tube for a little 4.25" RFT. I used flat joints glued with polyurethane and it was plenty strong. Maybe for a very long tube the birds mouth edges would be better? Any pics of the one you did?

My thought would be that a 12" X 12' wooden tube would be relatively heavy. How much did the 5' one weigh? How thick is the wood for the staves?

Let us know if you go ahead...we're interested in seeing the results.
Bill[/COLOR]

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Kreig,

I built a wood tube for a 6" f/8 by using 1/4 x 1 inch oak strips with edges cut to the proper angle on the table saw and finishing with polyurethane. Jigs and feather boards were used to obtain consistent and safe cuts of the small pieces. I used a gluing form composed of two plywood discs joined by a 1" dowel in a "axle and wheels" type setup (cover the "wheels" with wax paper for proper release). Glue all but the last slat and use a staple gun to attach them to the form. Once dry, remove the staples and gluing form before gluing the last strip and wrap with string or straps as clamps.

I found construction relatively easy but then I wasn't trying it with a 12". It seems to me that it could all be scaled up (wider and thicker slats) but weight and strength would become an issue. If it were me I would probably use spruce for its strength to weight ratio, glue with fiberglass epoxy, and finish with a very light weight epoxy fiberglass cloth to provide strength. With the fiberglass you could probably still use 1/4" thickness slats. Do not use plywood for the slats if you use carpenters glue because the end grain is a very poor gluing surface.

Perhaps those with more experience in fiberglassing than I would be able to comment on if this sounds like a viable plan.

Good luck and keep us informed of your progress.

Mark Eschbacher

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Search the forum history.

Several years ago there was one true artist in wood tubes posting almost daily, he even gave tips on calculating cutting angles and making suitable jigs for assembly. IF I remember his name it will be posted. Not quite the intricate stuff Normand Fullum does but beautiful, functional work.