From: griestk@wpi.WPI.EDU (Professional Freak)
Date: 6 Dec 93 08:06:43 GMT

In article <CHH8Cu.4AM@cnsnews.colorado.edu>,
Panther Modern <raymondb@ucsu.Colorado.EDU> wrote:
>  I used to have plans for something called an "ice gun"  It was a device
>which used dry ice routed through pipes to fire projectiles, the author 
>reccomended AA batteries.  Anyway, I know that isn't really pyro, but it
>seems to be related.. So if anyone has it, I would appreciate if you could 
>post it on here.  THanks.

This is AN article on dryice guns, exactly as I got it, so tab damage or
whatnots aren't my problems.  I personally haven't had opportunity to play
with this, due to the lack of initiative to go track down some dry ice... 
Good luck, though, and be careful...
----------------------------
From: floater@hardy.u.washington.edu (Auston Peddicoat)
Date: 19 Oct 1993 04:04:40 GMT

I found the following file and thought it was interesting enough to try.  
Anyone out there ever try somthing like this?  If so I would appreciate 
some more info (ie: if it works!, modifications, etc).  Here it is:  
(spelling mistakes aren't mine!)

     In the past, many people have experimented with the power generated
by the conversion of  dry  ice  into  gaseous  carbon dioxide.  The most
common use that I have seen is the dry icy ice bomb is  easily  made  by
using  a  two  liter plastic bottle, some hot water and some crushed dry
ice.  To make one, one simply puts about a cup and a half of crushed dry
ice into the bottle,  adds  hot  water,  caps  the bottle and throws it.
These bombs are not a joke, and have been known to blow  a  metal  trash
can  fifteen  feet  into  the air, as well as bursting the bottom of the
can.  If you make  a  dry  ice  bomb,  you  had  best throw it before it
explodes due to the enormous  force  generxplosion  of  the  bottle.   A
friend  of  mine  waited  a  bit too long on throwing one, and he jammed
three of his fingers badly, got a  huge  bruise on his left leg, and one
of the plasic fragments was propelled with enough force to puncture  his
tennis  shoes  and  cut his foot all to hell.  In short, be careful with
these things.

     One day in May of 1985, an  idea  was introduced to me by a friend.
His plan was to control the force of the expanding dry ice  and  harness
it  to  a  useful end.  The r ice gun.  In following these plans, please
keep in mind that when  dry  ice  is finished expanding, it can generate
pressures of up to 2400 PSI...for this reason,  I  recommend  that  when
arming the gun and when disarming it, you hold all valves OPEN, and that
you  wear  a  pair  of  protective goggles at all times.  I will take no
responsibility for injury that  occurs  because  of  the content of this
file, or through the use  of  this  information.   This  information  is
intended for educational purposes ONLY.

Materials needed:
----------------

     The  materials  required will vary for each gun produced because of
the nature of the construction  itself  and the effect produced by using
different parts.  The following parts, however, are necessary for a  gun
with moderate power and range:

     1- Standard  valve.  I recommend the kind that is just a lever and
        turns 1/4 turn to open or close and has 3/4" connectors.

     1- Blow gun  (These  can  be  found  at  auto parts stores...  shop
        around a little and get one with the highest pressure rating you
        can find (probably 150 PSI)).  This will be  sometimes  referred
        to as a valve also.

     1- Length  of  hot  water  PVC  piping...this will be used for the
        barrel.  I recommend that you  use  3/4" piping, because that is
        the kind that fits paint pellets of  the  type  used  in  KILLER
        best.   Note, however, that it is possible to launch anything up
        to the size of  an  egg  with  plea  provided that the barrel is
        large enough in diameter.

     You  will also need various lengths of regular lead or steel piping
(to construct the actual gun), and  adapters  to get the blow gun to fit
the rest of the gun (blow guns usually have connectors that are 1/4"  in
diameter,  while  the  rest  of  the  gun (except the dry ice container)
should be constructed with 3/4"  fittings).   You  will also need an end
cap to go on the end of your dry ice container  and  probably  an  elbow
joint.ts: --------------

     1- Standard valve (same  kind as above,  but with a  shorter
        lever).

     1- "T" joint with 3/4" connectors all around.

     1- 6 or 7 inch length of 3/4" diameter pipe.

     1- 3/4" end cap.

     Form-a-gasket and pipe dope

Construction:
------------

     Because  of  the  nature  of  the  gun,  step-by-step plans are not
possible.  However, a diagram of the  gun  will give you an idea of what
has to be done, and construction tips should prove enough to allow focus
the project.m: -------

   trigger (part of the blow gun)   standard
   adaptor______________        :    valve
                        \       :        \
                         :      :         :
  ______________________ :    _ ;    _____:______
 !                      !\__ __!__________________________________ /!        \
 !  barrel              ! __!__!__! !   O  !      \
 !______________________!/  joint B____________/  :  :  :    I     \     \
       blow gun_____________/   :  :    I    / \     \
                     er________/   :    I   /  !_____!<-joint A
       adaptor____________________/        /   !     !
       elbow joint________________________/   /!     !
       dry ice container_____________________/ !     !
       end cap_______________________________ _!_____!_
                                             \!!     !!
                                              +-------+


NOTES:

     1- The dry ice container can be any size...the one I use is about 6
        inches long by 2 inches in diameter.  The lare chamber  is,  the
        more shots the gun will fire before reloading is necessary.

     2-  The  elbow joint can be left out...it will only make the gun in
        the shape of  a  straight  rod  rather  than a "traditional" gun
        shape.

     3- The barrel length can be any length you like, but very long ones
        are cumbersome and very short ones don't allow much accuracy.  I
        recommend a length of about 2 1/2 to 3 feet.

     4- All joints except the two mar' should be tightened  as  much  as
        possible   and   sealed   by   coating   the  threads  with  the
        form-a-gasket and  then  putting  the  two  pieces  together and
        tightening them as much as possible.  If you like, you can  also
        caulk around the finished and tightened joint.

     5- The joint marked 'B' should be  tight, but DO NOT SEAL IT unless
        you do not intend to ever use more than one kind of barrel.

     6- The joint marked 'A' should not be sealed with  formt  like  the
        others  because  it  is the one that you will be filling the dry
        ice into the gun through.  To  fill the gun with dry ice, detach
        the dry ice  chamber  pipe  from  the  elbow  joint.   Load  the
        container  with  as much crushed dry ice as it will hold.  Then,
        coat the threads of one  of  the  pieces  of the joint with pipe
        dope.  This will prevent leakage of the carbon dioxide after  it
        has changed into gaseous form.

     7- amber should be about 1  1/2  inches  in  length  for  a  fairly
        powerful  gun.   The  longer  the  pressure chamber is, the more
        powerful the gun.  On a gun  with a three inch pressure chamber,
        we shot a AA battery 500 (yes, hundred) feet  across  a  parking
        lot.   Such  high  power,  however,  is  dangerous,  and  is not
        recommended for use  in  games  such  as  Killer, but rather for
        target practice (on INANIMATE objects).

How to operate-----------------------------

     Once you have the dry ice gun built and loaded, the first thing you
must do is to open the standard valve and  immerse  the  gun  in  water.
This is to check for leaks.  If any leaks are present, they will show up
as  streams  of  bubbles rising from the gun.  If any are found, tighten
the offending joint and put the  gun  back in the water.  When all leaks
are gone (if necessary, take the whole thing apart and rebuild  it  from
scratch  to  eliminate leaks, eher end of the pressure chamber), release
the pressure built up  so  far  by  closing  the standard valve and then
operating the trigger.  You should hear a 'woosh'  sound,  and  the  gun
should  kick  slightly.   This  indicates  that all is working properly.
When loading the dry ice gun,  it  is important to keep both valves OPEN
until the dry ice container is secure, and then close both valves.  Even
after you are sure that the gun has no leaks anywhere,  it  is  good  to
immerse  the  dry ice c it is attached to the gun) in water.  This warms
the dry ice and causes it to change into gaseous carbon dioxide.

     After the dry ice container has  been immersed for 5 minutes or so,
remove the gun from the water and dry it off.  The gun is now  ready  to
be fired.

Firing the dry ice gun:
----------------------

     This is the simplest step of all.  To fire the gun simply place the
projectile  (I  recommend  paint pellets) in the barrel of the gun, open
the standard valve for about a  second  e it.  You should hear a muffled
rush of air as some of  the  gaseous  CO2  is  bled  into  the  pressure
chamber.   Aim  the gun at who/whatever you wish to hit, and squeeze the
trigger.  For more power,  you  can  leave  the  standard valve open and
squeeze the trigger.

Disarming the dry ice gun:
-------------------------

     To disarm the gun, open both valves until you can  no  longer  hear
the  pressure escaping through the barrel of the gun.  Then, unscrew the
dry ice container and place it in  cold  wa 3 to 4 minutes, or until all
of the remaining dry ice has evaporated.  When all of  the  dry  ice  is
gone,  clean  the  threads on the dry ice container and elbow joint, and
store the gun in a clean, dry area.

Suggested modifcations:
----------------------

     The only  really  nice  modification  that  I've  discovered  is to
replace the pressure chamber pipe with a "T" joint and valve  so  as  to
make  a  gun with long, medium, and short range capability.  To do this,
construct the pressure chamberhe gun like this:

          ___adaptor                                       I
         :  ______________________________________ ________I___
 _____ _ :/!                                      !        I
___#__!o!/ !                                      !        I
        !  !                                      !        I
        !  !        "T" joint                     !        O
________!  !                                      !
:        \ !                                      !
:         \!_____       _____________!____________
:                      !             !                 ^
:                      !_____________!                 !
:__blow gun            !______O______!<-standard       standard
                       !      I      !  valve #2       valve #1
                       !      I      !
                       !      I      !<-short length
                      _!______I______!_  of piping
                      !!             !!
                      +---------------+
           end cap___

     What this does is make  a  pressure chamber with a variable length.
The following chart shows the combinations in which the  valves  may  be
used to create different ranges.


 RANGE  !  INSTRUCTIONS
--------+--------------------------------------------------------
 short  ! Open valve number 1, hold it open for about a second,
        ! close it, and then open valve #2.
--------+--------------------------------------------------------
 medium ! Open valve number 1 for about a second and close ite valve #2 closed.
--------+--------------------------------------------------------
 long   ! Open valve #2 before opening valve #1.  Open valve #1
        ! for about a second, then close it.
--------+--------------------------------------------------------

     The  trigger can be squeezed at any time following any of the above
procedures.  Have fun!

------------------------------------------------------------------------------

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