DIY glass fibre plenum chamber? Bad idea?

[Gary Ohst]

For high tempature composites, I have only heard of two.  One is Nextel
from 3M slightly weaker than fiberglass, but able to handle 2000 degrees
F.  Ceramic weaves are also appearing.  Strenght is near that of
fiberglass and they can handle 3000 degrees F.  Cost is way up there at
$170 per square yard compared to $20 per yard for Kevlar.  For more info
try the self-published book "Composite Basics" by Andrew Marshall c/o
Marshall Consulting, 720 Appaloosa Dr., Walnut Creek, CA 94596.  It's
one of the best I have seen.

Also...

Kevin Vannorsdel wrote:

>>When I was in College we used a material called Spectre from Allied Signal.  It
claimed to be better than Kevlar in nearly all categories...  I think it
may
have had a temperature problem though... can't recall.<<

Spectra is the lightest of all the fabrics.  It will float on water.  It
is difficult to get a good resin bond with Spectra so its use in
laminates is limited at present.  It is replacing Kevlar in high
performance rope construction.


>> I worked with kevlar a bit this past semester in school and was kinda
disappointed because it wasn't all that "it was cracked up to be." We
had a
plate consisiting of 30 layers of pre-preg uniderectional kevlar (laid
up in a
criss-cross fashion...each layer rotated 45degrees relative to previous
layer)
and it couldn't stop a 9mm...albeit it was shot from point blank
range.<<

The layup method can have a large impact on the resulting strenght.  Any
excess resin will weaken the final product.  Vacuum bagging is used to
help extract excess resin from the matrix.  Also, curing the layup under
under both pressure and temperature can add additional strenght.



And Orin Eman wrote:

>>Speaking of Kevlar and related fabrics, does anyone know of a source
of very thin Kevlar cloth?  (< .005").<<

Try:

Aircraft Spruce & Specialty Co.
Fullerton, CA (800) 824-1930

Kevlar 49 , Style 120 , 1.8 oz/yd , Thickness =.0035 

Hope this helps.

--Gary--