Re: [ATM] Strip planked telescope tube

["Virgil.Johnson" <virgilaj@charter.net>]

>I was thinking about tube ideas for a 14 inch cassegrain and came across an 
>S&T article from November 1991.  I also saw a couple references to the idea 
>by Kurt Maurer in the archives.  The process inolves building a form from 
>strips of wood (usually cedar) and then applying fibreglass cloth and epoxy 
>to the inside and outside, creating a composite tube. I understand the 
>strip plank approach is commonly used to build boats.
>


I have a 14 inch diameter tube made from redwood strips in this fashion. I 
man I work with, made it as a woodworking experiment prior to making a 
canoe. He used a set of router bits to mold the edges to a convex curve and 
a matching concave curve on the opposite edge. (_____( .   He used several 
disks cut to diameter and held with pipes thru the centers. Wax paper was 
between the disks and the slats. The slates were epoxied edge to edge and 
stapled to the disks. The rough shaped polygon was then attacked with a belt 
sander to round out the surface. I use the word attacked because I had to 
learn about the maximum radial velocity a spinning slat tube can take when 
powered by a belt sander. I learned about max velocity, but can't quantify 
it, things fell apart to fast.

After the tube was put back together and rounded in a sensibly way, the 
cloth and epoxy resin was applied. tube was rotated SLOWLY, to prevent runs. 
After sanding, the resulting tube looks like a piece of furniture.

The 14 inch diameter is pretty tight for a 12.5 inch at the top end.

Virgil Johnson
Raider of the Lost Dark 

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