hey,Tyler, you wanna field that one?????
Why yes, Derrel, I'd love to.
A bong, or "water pipe" is a smoking device which uses a water filtration method of cleansing the smoke that you inhale. You can get variations of bongs ranging from simple ones, to glass on glass behemoths with inline percolator and ash catchers.
However, the type of bong that I am referring to is one that uses a vacuum. Which is odd that it's called a gravity bong... But oh well. A gravity bong is what you would use to conserve what you are smoking and get the most out of it at one time.
You need:
A large pitcher for iced tea, or water
A 2L coke bottle
A slide from a conventional straight shooter bong
A 3/4" drill bit to drill through the 2 liter cap
and a ping pong ball
(also something to smoke would be preferable.)
You fill up a large (usually about 3.5L or so) cylindrical container with water.
Cut the bottom of the 2L off just enough so that the 5 points on the bottom are gone and you have the majority of the 2L intact.
You then take the 3/4" drill bit and drill through your cap so that the slide can fit down through. I've found that this makes a very tight seal and is great for maximum yield per pull.
After that, put the slide in the hole, and fill up the cavity with some variety of plant matter.
Okay, so now you have a cap with a slide attached to it, a 2L with the bottom cut off, and a pitcher full of water. Now place the ping pong ball in the water and put the 2L over it. When you inhale, the ping pong ball will keep you from ingesting bong water which can be very disgusting.
Okay, all most ready for lift off! Now that you have the 2L in the pitcher with the ball inside, put the cap on the bottle. Since the bottle is completely filled with water, when you pull it out of the water, the only inlet for air is through the slide which you fashioned on the cap. So if you light the plant matter, the 2L will fill up with smoke as you lift it. This is where the vacuum comes into play. After you have the desired amount of smoke, you unscrew the cap and inhale deeply. The bottle will get sucked down towards the water level as you inhale, but the ping pong ball will be there to save you.
After that, you might as well pack a suitcase. Because you're about to fly.
Hope this clears up any confusion.
Love,
Tyler