What is a gravity bong and how do you make one?

Published on January 10, 2022 · Last updated May 9, 2024

What is a gravity bong?

A gravity bong is a cannabis consumption method that uses two empty plastic bottles to funnel smoke through water and push it into the consumer’s lungs. A gravity bong is also known as a geeb, grav bong, or gravity pipe.

Gravity bongs work by submerging a small bottle with a bowl of cannabis on top in a larger bottle or bucket of water. While lighting the cannabis, slowly draw the bottle out of the water to fill it with smoke from the burning cannabis. Unscrew the lid, put your mouth over the bottle’s opening, and push the bottle down to let gravity propel the cannabis smoke into your lungs. Voila!

Do gravity bongs get you higher than other smoking methods?

The short answer is yes. Gravity bongs force heavily concentrated smoke into your lungs, filling them to capacity beyond the average hit from a pipe or joint. When you inhale the contents of the smoky bottle into your lungs, you are essentially breathing in the smoke from an entire bowl of cannabis in one go. For this reason, gravity bongs are certainly not for the faint of heart. Gravity bongs are a tried-and-true method of old school cannabis consumers. They deliver a powerful hit of THC that may be too much for an inexperienced cannabis beginner, so gravity bong-er beware.

However, if you’re trying to stretch your stash, looking for a bit of nostalgia, or feel like getting crafty with your cannabis consumption, here’s a handy guide to creating your own gravity bong using a few everyday household objects.

Disclaimer: Inhaling combustible materials from a plastic smoking device may be hazardous to your health. Proceed at your own discretion!

Store-bought vs. homemade gravity bongs: Should you buy or make your geeb?

If you’re new to cannabis or have a low tolerance, you probably don’t want to start with a gravity bong. But for intermediate to advanced consumers, making a gravity bong is a fun, easy DIY project that ensures a fast and efficient delivery of your favorite strain.

Not the crafty type? You can buy gravity bongs to add to your collection of hardware and bust one out whenever you want a unique and potent smoke session.

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Are water bottles safe to use?

Many homemade bongs or smoking devices are made using single-use plastic bottles, which contain PETE or PET (polyethylene terephthalate), which can release chemicals when heated (just like the water from a bottle that’s been left in a hot car can taste odd). You may pull these chemicals into your lungs when applying heat to your gravity bong.

Are water bottles safe to use as a geeb?

Research is still being conducted on what sort of impact this type of exposure may have on your health. Many cannabis consumers prefer to use glass or silicone smoking devices and avoid plastic as a precaution. If you choose to make homemade gravity bongs and other smoking devices out of plastic materials, be aware of the risks and proceed with caution.

If you choose to make a homemade gravity bongs or other smoking device out of plastic materials, be aware of the risks and proceed with caution.

How to make a homemade gravity bong

gravity bong materials
Materials for making a gravity bong. (Leafly)

Supplies needed:

  • Plastic bottle with cap (any size, but 16-20 oz. is ideal)
  • Bucket or 2-liter plastic bottle
  • Aluminum foil
  • Box cutter or sharp knife
  • Poking device
  • Cannabis (at least one gram)

Gravity bongs can be a bit intimidating if you don’t know where to start, but the procedure is more straightforward than you might imagine. It just requires a little ingenuity, some creative efforts, and the determination to make it work, and in less than 10 minutes you can construct your very own gravity bong using materials you probably already have at home.

Step 1: Cut the bottles

gravity bong
Cutting the small bottle. (Leafly)

Use your box cutter to cut the bottom off your smaller bottle. The more of the bottle that remains, the larger the hit you’ll receive, so be careful not to trim too much off the bottom of the bottle.

Step 2: Cut the larger bottle

Cut the bottom off your larger 2-liter bottle and fill it with water. If you’re using a bucket, fill your bucket with water.

Step 3: Make a hole in the bottle cap

gravity bong
Fashioning a DIY bowl. (Leafly)

Unscrew the cap to your smaller bottle and use your box cutter or scissors to make a hole in the bottle cap. It should be big enough to draw air through, but not so big that the foil (and cannabis) will fall through into the water.

Step 4: Shape the foil bowl

Wrap the cap in aluminum foil, shaping the foil to create a small “bowl” divot for your cannabis. You can shape the bowl to be as deep as you’d like, and the foil will keep your cannabis from falling into the water below. You may need to cut off excess foil and shape it to avoid spilling cannabis. Health hack: If you’re looking to spare your lungs, try this metal bowl piece specifically designed to be used for gravity bongs.

Step 5: Poke holes in foil

Use your sharp poking tool to make holes in the aluminum foil. Be careful not to rip the foil! You’ll need about 3-5 holes for proper ventilation.

Health hack: You can also use a glass or metal bowl from another bong or other smoking devices to avoid the foil.

Step 6: Load cannabis in bottle cap

Fill the large bottle or bucket with water about 2″ from the top.

Load the DIY bowl (the foil-covered bottle cap) with weed, but don’t screw it on just yet.

Step 7: Submerge small water bottle

gravity bong
Submerging the small bottle. (Leafly)

Here’s the tricky part: Submerge the smaller bottle in the filled bottom half of the larger bottle (or bucket) until just the cap remains above water. Carefully screw the foil-wrapped bottle cap back onto the bottle.

Carefully screw the bowl back onto the bottle.

Step 8: Light your cannabis

gravity bong
Drawing up smoke into the gravity bong’s chamber. (Leafly)

Light the cannabis and slowly pull the smaller bottle upwards out of the water while the bottle fills with smoke. If the bottle doesn’t fill with smoke, you may need to check and make sure that your cap is fully screwed on, and that there are no holes or gaps in the side of the bottle. Any leaks could compromise your gravity bong, and some trial and error may be required before your first successful attempt at a functional device.

Step 9: Unscrew the cap

gravity bong
Hitting the gravity bong. (Leafly)

Once your bottle is filled with smoke, carefully unscrew the cap and put your mouth over the bottle opening.

Step 10: Push the bottle into the water

Gently push the bottle back into the water. As the water enters the bottle, the smoke will be pushed into your lungs.

The cannabis smoke will be cooler, having been filtered through the water, but it will deliver a powerful hit of THC. For best effects, prepare yourself and don’t force yourself to inhale too much smoke. This has the potential to make even the most veteran of cannabis consumers cough, so proceed with caution!

How often does the foil in your gravity bong need to be changed?

You can reuse the foil in your gravity bong. Don’t worry about changing it unless you rip the foil or if the holes get clogged and prevent adequate ventilation, at which point you should swap it out with some new foil.

Alternative method: How to make a waterfall bong

A waterfall bong is slightly different from a gravity bong. A waterfall bong is a pipe that uses water to create a thick, dense cloud of cannabis smoke that users can inhale from the opening of a plastic bottle.

There is a small difference between a gravity bong and a waterfall bong, but it is a significant difference. While a waterfall bong does use air pressure to draw smoke into the bong, much like a gravity bong, the difference is in how the air pressure in the bottle is changed.

A gravity bong is raised above the water, which created a vacuum when the bong is shifted upward. The key difference is caused by a hole that allows the water to flow out. The “waterfall flow” causes the change in air pressure that fills the chamber with thick clouds of smoke.

Making your own waterfall bong is simple, and similar to making a Gravity bong from scratch. Here’s how to make your own waterfall bong.

Here’s what you need to build a waterfall bong from scratch.

  • Plastic Bottle
  • Aluminium Foil (or Glass Bowl)
  • Knife

First, make a small hole in the side of your plastic bottle, close to the bottom. This hole will sprout the waterfall when your bong is completed.

Next, use the foil to make your bowl. You can use aluminum foil or tin foil. Some users pack the plastic bottle cap in aluminum foil and punch holes in it to make the bowl that holds the buds in place. But if you choose tin foil, it’s better to make a standalone bowl out of tin foil, to avoid inhaling plastic fumes when you heat the cap. Mold the foil like a bowl covers the bottle opening, then punch a few tiny holes under the bowl to let the smoke escape.

If you use this method, don’t forget to plug the water hole with your finger while filling the bong up with water and weed. Pro-tip: Use a bong plug or carbhole plug to plug the hole. That will make your life infinitely easier. All you have to do is remove the plug as you light your bowl and the bong will fill up with smoke.

To inhale, remove the bowl, and inhale from the top of the bottle. You can also make a separate hole close to the top of the bong, and use a bong plug or carbhole plug to keep the vacuum airtight while your bong is drawn full of smoke.

In addition to a water bottle, you can use a milk jug, a rain barrel, and many other plastic bottles.

Lisa Rough, Calvin Stovall, and Pat Goggins contributed to this article.

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