we went to a garage sale today and bought a perfect fire extinguisher for a $ 1.50 but im sure most people wont be that lucky so i would look at garage sales and on craigslist and other places for one it should be a large fire ext. i think mine is like a 2 gallon .
Step 2: Preperation
remove nozzle apparatus and fill about half way to 2/3's full and put apparatus back on ( make sure it is on correctly and very tight )
Step 3: Compression
after you tighten everythig up your ready to compress it . on most of the fire extinguishers at least the older ones have a bicycle valve so you can compress it . when you are compressing it listen for leaks and any wierd sounds except for a bubbling sound in the container that is fine .
compress to 100 psi ( most fire extinguishers have a meter )
Step 4: Fire at will
pull the safety pin if there is one and it should shoot 25-30 feet in a strong beam of water.