This bong is probably the easiest to make out of all of the bongs you can make. The only hard part is where are you gonna get a water cooler? Steal one. Okay, know that is out of the way, this bong can be made into a single hitter, a 2, 3, or 4 hitter. It doesnt matter, it just depends on how you want to make it.
Here is what you will need to make a water cooler bong.
A metal bowl, or a socket as big as you want.
A faucet screen (dont wanna waste weed!)
A long stem you can use PVC for this one.
A water cooler, and a cap for the top, my friend cut off the bottom of a soda can and got that on top of there, but if not, just put tape there. Electrical so it doesnt burn.
A knife, or pair of scissors for as many entry holes as you need.
Some PVC tubing or a hose.
First, fit some kind of a cap on there. Or, if you cant get a soda can to work, then just wrap a tight seal of tape on there. Then, make as many entry holes as you are gonna make the bong, 4 holes for a 4 hitter. Make them big enough for PVC or a hose to fit through. If the seal isnt airtight, than wrap some tape around there. Then, place the bowl/socket on top with the stem making an airtight seal. Then just pack and toke. Also, make sure that the stem is long enough to be in the water about 8 inches down.