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- [][][] A Step by Step Guide to Making a Dry Ice Gun [][][]
- [][][] [][][]
- [][][] By: The Voice Over [][][]
- [][][] [][][]
- [][][] A Metal Communications Presentation [][][]
- [][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][]
-
- Introduction:
- ------------
-
- 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 ice
- bomb. The dry 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 generated
- by the explosion 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 result was the dry 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
- pleasing results, 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.
-
- Optional parts:
- --------------
-
- 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 successful completion of the project.
-
- Diagram:
- -------
-
- trigger (part of the blow gun) standard
- adaptor______________ : valve
- \ : \
- : : :
- ______________________ : _ ; _____:______
- ! !\__ __!___/! ! \
- ! barrel ! __!__!__! ! O ! \
- !______________________!/ / : : \!___I__!__ \
- joint B____________/ : : : I \ \
- blow gun_____________/ : : I / \ \
- pressure chamber________/ : 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 larger
- the 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 marked 'A' and 'B' 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 form-a-
- gasket 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- The pressure chamber 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 the dry ice gun:
- ------------------------------
-
- 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, especially on either 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 container (while 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 and
- then close 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 water for
- about 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 chamber section
- of the 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 it.
- ! Leave 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!
-
-
- This file may be used on any system as long as all credits and
- information remain intact.
-
- =================================================================
-
-