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> My thought was the same as Paul's.  But some of you are likely not 
> familiar with Sintra (and other plastics companies call it different 
> things).  It's a plastic sheet material made of PVC that comes 
> anywhere from 3mm (1/8") thick (and thinner too, but not often used) 
> and up in bright primary colors (red, yellow, green, blue) plus black, 
> white, gray and tan.  It's somewhat flexible and fairly lightweight. 


 It's inexpensive:  $30-40 for 1/8" thick 4' x 8' sheet if you buy it 
from a large plastics firm and can pick it up, but you can get smaller 
pieces as well from local plastic or sign fabrication shops if you live 
outside a big city, or possibly find a supplier who will cut it into 
smaller pieces so it can ship regularly.  The beauty of it besides cost 
is that it is easy to cut with a bandsaw (or utility knife in several 
passes for 1/8" thick), and glues together really nicely with PVC cement 
(used in plastic household plumbing, this actually melts the plastic 
together, called "solvent welding").  You might want to make a sandwich 
of several layers in different colors.  You could use a Dremel tool or 
file or whatever to put permanent marks into the plastic for the gnomon. 
 You can heat it up and bend it to various shapes (within reason).

The color will gradually fade over time outside.

Another source for basic dark gray PVC sheet is www.mcmaster.com-- you 
can get small quantities, altho' it's more expensive per square foot 
than Sintra in bulk;  you can also get rods and tubes and things that 
you might want to use.

Check out the website Paul listed below for sources for plastics.

Kathy Krafft
Exhibit Projects Director
Sciencenter
Ithaca, NY

> ------------------------------------------------------------------------
> ********************************************************
>
> Faced with your criteria,  I would use Sintra for the circle and  
> gnomon.  As an alternative, what about sanded and coated "tree  
> rounds"  (eg log cross sections).
>
> Paul Orselli, President and Chief Instigator
>
> The Great Big List of Exhibit Resources:  http://www.orselli.net/ 
> sources.htm
>
>
>
>

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