Re: ATM Composite Tube

["Dave Pitou" <dpitou@ix.netcom.com>]

Composite refers to the fact that the tube is made out of three different
materials. The inner layers are fiberglass cloth, (or carbon fiber, or
Kevlar), and epoxy resin, the middle layer is stiff urethane foam or
styrafoam, or honeycomb, and the outer layers are an exact repeat of the
inner layers. The tube stiffness comes from the seperation of the inner and
outer layers, which is the only function of the foam - keep the layers
seperated. Because the stiffness comes from the layer seperation and not
the their thickness you can use very thin, (read light), inner and outer
layers. I use 2 or 3 wraps of cloth with a seperation, (foam thickness), of
3/8" to 1" depending on tube diameter. 

The $800 tube guy uses female forms, (form is outside the tube), but I use
male forms - usually a Sonotube. So possibly your old tube could be a form
for your new one. New tube would be a bit larger, but heck you'd get better
ventalation!

If your'e still interested I can describe how to make one, but it will be
kind of a long message, and work is already calling!


dp2
----------
> From: Jack Schmidling <arf@mc.net>
> To: atm-digest@shore.net
> From: "Dave Pitou" <dpitou@ix.netcom.com>
> Subject: Re: ATM Why Sonotubes?
> 
> "Actually the $800 composite tube is pretty easy to make, and not that
> expensive...
> 
> I was referring to a quote for a ready to use tube.  Unfortunately,
> the "boss" is pretty firm about not authorizing that much for a tube
> for a scope that she thinks works just fine.
> 
> Anyway, I would like to know more about this "easy to make".
> 
> Let's start with the word "composite".  Just exactly what does that
> mean?  What is it made of and how does one make one?
> 
> Sounds like an alternative to drilling lots of 3" holes in my
> Sonotube.  Not a bad idea but just haven't brought myself to do
> it yet.
> 
> js