If you can obtain a good metal cracker then do so, all homemade devices may break and are asking for trouble. Spilling some bong water is nothing compared to losing patches of skin due to frost burn from escaping nitrous. Here are some comments from people who have sucessfully made their own nitrous oxide crackers.
I don't know about other states, but dispensers are not available in Kansas. A friend has one, but he is from Missouri and I don't know where he got his. However, for about $2 you can make your own with PVC pipe parts from any hardware store.
All you need is a "T" or "L" pipe with threads in one end, a nail, a pipe fitting for the cartridge, and some silicon sealant (make sure it says "food contact surface safe"--you don't want to inhale noxious sealant stuff).
I put mine together like this:
------------------------------- balloon here --> | <--nail || cap this end | || ------------ ------------ | | |= =| |= =| <---threads in this end ^ | | | cartridge holder screws in here =| |= <---threaded end =| |= / \ | | | | | --- | ------- plug fits in bottom (you'll have to play with it a little to get the correct length for the nail to pierce the cartridge)
I don't remember which size nail I used, as it was an a variety pack with all sorts of tacks and stuff. Glue the nail in first with shitloads of the silicon sealant, and then you can fiddle arount with the cartridge holder part to get the correct length. The pipe parts are 3/4 inch. If you bring a cartridge with you to the store you can find the parts easier. A friend made one with an "L" shaped top part instead, and it works fine too.
When the whippit comes out, it is VERY VERY cold. Don't get your hands anywherenear the stuff, and don't use METAL pipe for a dispenser or you will burn yourself and this sucks. (Eds note: or USE metal pipe but wrap it with an insulator like a washcloth. That cold has to go somewhere and you might as well sink it into the metal rather than the balloon.)mangar@XXX.edu
I too, have a homemade version I made out of PVC pipe. It never occurred to me that they'd *sell* the crackers as well as the cartridges. My design is very similar to the one posted, except I used an angle piece instead of a T. It looks very similar to an asthma inhaler, but won't work like one. With this design you don't need and sealant either.
As far as the extreme cold produced - I load the cartridge, screw it in to the point just before it gets punctured, and fill the area left in the PVC with water. Hot water works slightly better, but just slightly since the water turns quickly cold. Attach the balloon, and puncture. Then it's just a matter of keeping everything facing up so the water covers where the nitrous comes out. It's a bit of a pain when filling a balloon with more than one cartridge, but before using this, I had a couple freeze closed before they were completely empty. It hasn't happened since I started using the water method.tmcdonal@XXX.edu
I have constructed an N2O cracker by utilizing a Boiler tap fitting from a plumbing supply store [Eagle Hardware].
The tap has to have the following configuration:
| | <- screw fitting for hose | | | ________|___|___________ | | ||||| |-----| ||||| | | ||||| | |___________________||||| ^ ^ | | Handle for valve screw threads
There is typically a rubber washer screwed into the top. Remove the screw and the washer. Replace the screw with another screw, which you have cut the head off and sharpened to a point. This is what punctures the cylinder. Get a fitting to close off the bottom, that screws easily on and off, add a little cork or pvc inside to keep the cylinder straight. Use a balloon on the hose fitting side, and you have your cracker!
If you post this anywhere, use some other name for the source, like "omegaman" or something equally inane. I will not feel offended for not being given adequate credit.