I don't know the composition, but I have noticed something about this type
of extinguisher, which could give people a false sense of security.  Most
owners may only occasionally look at the pressure gauge, to see if the
needle reads "OK" or "LOW", or press a "Test" button, as their preventive
maintenance.  I read an article somewhere, that advised shaking the
extinguisher before use, for maximum effect.  Apparently, the powder has a
tendency to cake or clump together over a period of time, which can cause
most of it to not be expelled with the compressed air, when the trigger is
pressed.  I believe that this problem may be even worse in extinguishers
that are secured vertically in a vehicle (like the original ones mounted in
Westys), due to the constant compression pounding the powder takes when the
vehicle goes over bumps, etc.   I have routinely shaken the (usually old)
extinguishers in vans I have bought, and after hearing nothing moving inside
of them, have had to violently agitate them or smack them hard with a rubber
mallet several times while holding them upside down, before I could hear the
powder move around.  Although I have never actually tried using "unshaken"
extinguishers as a test,  I'm not going to wait for a fire, before I shake
my extinguishers.  This may be another good reason to consider Halon type
extinguishers.

Cary

----- Original Message -----
From: Ken Lewis <kdlewis_wasting_time@ACCESS4LESS.NET>
To: <vanagon@gerry.vanagon.com>
Sent: Sunday, December 21, 2003 9:38 AM
Subject: Re: Vanagon fire fighting techniques

> I was told the powder is basically baking soda. True or false?
> Ken Lewis
> 86 Transporter Crew Cab
> 60 356 T-5 Porsche
> http://neksiwel.20m.com/
> Vanagon tech, pixs, O2 monitor gadget
> ----- Original Message -----
> From: "Edward Maglott" <emaglott@BUNCOMBE.MAIN.NC.US>
> .....  I found that on that extinguisher you could actually unscrew the
> valve off of
> > it and shake out the rest of the powder on the nearest burning
> item,.......
>
>