Ha. GB's are killer. Feels like I'm walking through a burning building and just taking a deep breath in. Ugh... Not something I recommend doing on a consistant basis unless you like black lungs.

Anyway, back at school we used to make them out of 3 liter soda bottles and a pitcher to hold the water. However, from what I've seen I (and my fraternity brothers) make them somewhat usual compared to most. We don't use a bowl head, we make our own bowl. I find this to be the *best* way to do it - ie: thickest smoke, strongest hit.

Take your 3L soda bottle, cut off the bottom as far down as you can (so the piece remining it as tall as possible). Take the cap, make a nice sized hole in it (slightly smaller than a dime, enough to fit a sharpie through with several sheets of tinfoil wrapped around it). Then break out the TINFOIL. This is the KEY.

Rip of several sheets of tinfoil about 6"x6" or so (aprox). Get a BIC pen (or something similar-sized) and mold/fit a piece of tinfoil to the bottom of the BIC pen about 1/2". Take the pen (with the alum foil still wrapped aroud it) and place it inside the hole you just made on the cap. Wrap and flatten the tinfoil around the cap and up underneath where the threads are. Continue this process ONE SHEET AT A TIME. Use about 10 sheets total or so. After you're done, take a SMALL pin and poke 1-2 holes in the bottom of the "bowl" you just made. The SMALLER the holes the BETTER. Take a lighter and pull a hit WITHOUT any herb for about 10 times to wear the cap in. It's not going to work well the first few times, but after about 20 or so it will be perfect. I've attached a few pics.

The hardest part is making sure you have a good seal. And make sure you use AT LEAST 7-8 sheets. Wrap them up well underneath the cap to make an airtight seal. After you're done, twist the cap on BUT SLOWLY. Don't crank down on it all the way, it will get stuck and you will not be able to take it off without destroying the nice new bowl you made. Twist it on until its somewhat tight, then loosen. Repeat until the tinfoil layers underneath the threads of the cap are nice and tight.

Tinfoil rips easily, so it takes some caution to ensure it works well. If you made one, packed a hit, and pulled it and not getting any smoke (or very thin smoke) you have a leak somewhere. The sign of a good GB constructed this way - let all the air out of the bong, and let it sink to the bottom of the pitcher. Twist the cap on snugly and then pull up - you should feel some resistance and water should rise up with the bottle as you pull. Also when lighting a packed hit, you should see the herb light up brightly as the air is being sucked into the bottle at a high speed.

I've smoked plenty of GB's in my day. Never have I smoked any with a bowlhead that comes anywhere hear to as strong as to the ones we make out of tinfoil. Granted this is an art, and it takes much practice to make a good one. But in the end it is well worth it. Also, we throw a pingpong ball in the pitcher, underneath the 3L bottle to ensure we don't accidently sip up any bong water (ew) - you can see it through the plastic in the pic of the whole bong. Give it a shot and good luck. Also be prepared to sit down right after you take it.