How to Make a Gravity Bong

by Doug

Learn how to make a gravity bong

Lots of recreational cannabis enthusiasts use bongs to enjoy their favorite strains of indica, sativa, or hybrid cannabis. But there are more bongs than just the commercial ones you can find in stores, and some bongs can even be created at home with a few common materials.

They’re called gravity bongs. Cool-sounding name aside, they’re some of the most effective and easy to create bongs, especially for folks with a little DIY instinct. Want to know how to make a gravity bong of your own? You’ve come to the right place.

What is a gravity bong?

A gravity bong, which can also be called a “geeb,” is a bootstrap bong that combines two empty plastic bottles to simulate the apparatus of a more professional or commercial bong.

In a nutshell, these bongs work when you submerge a smaller water bottle with a bowl of cannabis on top into a larger bottle or a bucket filled with water. When you light your cannabis, you’ll slowly draw the smaller bottle out of the water reservoir, which will fill with smoke from the burning cannabis.

You can unscrew the lid, put your mouth over the opening, and then press the smaller bottle down. The result? Gravity actually propels the cannabis smoke into your lungs without having to inhale (at least very hard). Kind of cool, right? While there are other ways to smoke cannabis creatively, there’s no denying that this style of bong gets a few bonus points since it looks like a science experiment.

Do gravity bongs work? Absolutely. In fact, they can even give you a, well, higher high than other types of bongs since the gravity from the reaction forces the concentrated smoke into your lungs. This often results in a more concentrated hit compared to a regular pipe or joint. Granted, this does mean that gravity bongs are best enjoyed by people who have some experience instead of beginners.

Guide to making a gravity bong

Making a gravity bong is simple. Here’s our step-by-step guide on how to do so.

What you’ll need for a gravity bong:

Before you begin making your own gravity bong, be sure to get the following materials together so you aren’t scrambling in the middle of the process.

  • A plastic bottle between 16 and 20 ounces
  • A plastic bucket or a 2 L plastic bottle
  • Some aluminum foil
  • A sharp knife or a box cutter, which is safer
  • A poking device; you can use a pencil or pen, or even a needle
  • Then make sure you have your cannabis strain of choice – you’ll need at least 1 g for this to work

On the topic of water bottles, you’ll want to be careful about the bottles you use. That’s because progressively heating and inhaling smoke that touches typical water bottles could result in you ingesting PETE or polyethylene terephthalate, which is a potentially harmful chemical, especially when absorbed through inhalation.

If possible, use water bottles that are not made with PETE plastic. You can alternatively use glass or silicone bottles or bowls. If you have those materials, just use those when you see any mention of plastic bottles throughout the following tutorial.

Step one

Ultimately, this process should take you about 10 minutes from start to finish.

To begin, take the smaller 16 to 20-ounce water bottle and use your box cutter to slice off the bottom half. Keep in mind that the more space that remains, the larger your smoke reservoir will be. That means your resulting hit will be more intense. Don’t trim too much of the water bottle to preserve this effect.

Then cut your larger water bottle. Do the same thing and slice off the bottom, then fill it with water. Alternatively, fill the bucket or bowl you chose with water instead.

Step two

Next, unscrew the cap for your smaller water bottle. Use your box cutter, scissors, or another slicing tool to make a hole in the bottlecap. Be sure to make the hole large enough that you can draw air through, but not so much that foil or cannabis will fall through into your water reservoir.

Step three

Now it’s time to shape the aluminum foil into a bowl for your cannabis strain. You can make this bowl as deep as you prefer, but chances are you’ll be limited based on the shape of your water bottle or lower bowl/bucket.

Feel free to cut off any excess foil; you only need enough to prevent your cannabis from falling into your water reservoir. Then use your poking tool to make holes in the aluminum foil. We’d recommend about 3 to 5 holes for optimal ventilation.

Step four

The next step is to load up your cannabis strain. Place it in the foil-wrapped bottlecap, but be sure not to screw the cap onto the top quite yet.

Step five

Time to submerge! This is the trickiest part of the whole process, so go slowly to make sure you don’t make a mistake.

Submerge your smaller water bottle in the bottom half of the larger bottle or bucket. Keep going until only the cap of the smaller bottle stays above water. Taking care not to shake either bottle or bowl, screw the bottlecap that has the foil wrapped around it back onto the smaller bottle.

Step six

Light your cannabis, taking care to pull the smaller bottle slowly upwards and out of the water. Remember: using a gravity bong is a little different than using a regular bong. The vacuum created by this method should result in a smaller bottle filling with smoke. If it doesn’t, go back and make sure the cap is completely screwed on and that there aren’t any additional holes in the side of the smaller water bottle.

If the bottle is filled with smoke, unscrew the cap and place your mouth over the opening. Then you can push the bottle back into the water. 

The smoke should rush into your lungs, giving you quite the concentrated hit! One bonus side effect of this is that the cannabis smoke should be cooler than average since it ought to have been filtered by the water. Again, take care not to inhale too much if you don’t have a lot of experience.

One last thing – you don’t need to replace the aluminum foil unless it rips or visibly starts to degrade. It’s a good idea to replace your gravity bong after a few days or weeks, though, just to prevent material degradation.


Easy as that! Anyone can make a gravity bong with the right set up and a little preparation. This style of bong has been a hallmark of college parties and DIY cannabis enthusiasts for decades. And if you’re not in the mood to do all that you can also make a simpler version using just one regular sized water bottle.  

A gravity bong is a great way to enjoy your favorite cannabis strains without having to buy a commercial bong or wait for delivery.

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