Note: This tutorial will work on tobacco waterpipes (bongs) with 4mm glass. It is easier to do than it looks. You just might have to practice with the glass cutter. If you like your bong a lot or if it was expensive, it is definetely worth it. Besides, once you have all the materials you can fix many bongs in future, too. Also, it is a fun project.

Time: ~60 minutes

You will need:
- A simple glass cutter, for example this one: Amazon.com link*
- Two component epoxy glue without solvents (you also can get food
grade epoxy if you want), DON'T use glass glue unless it is food grade and water resistant!!! Normal glue will not work! For example this one: Amazon.com link*
Advantage of epoxy: once dried out it is very hard, not toxic and the one I
have is also resistant to acid and bases (good for dishwasher tabs when
cleaning).
- A jetflame lighter or candle (for thicker/ thinner glass)
- Not to forget: A broken bong (whole percolator broken off or if an arm of the perc broke off)

* = These links are all amazon.com affiliate links

Step 1: Using the Glass Cutter

- wash your bong from the inside and outside with dishwasher tabs and hot water (that yellow thingy is the rest of a tab that didnt dissolve properly)
- then dry it off well on the outside
- find a stable and easily turnable position to (ideally) cut a perfect ring around the neck of your bong
- apply a little oil to the small cutting wheel of the glass cutter
- mark the place where you want to cut (in my case at the bottom so I can
get at the bottom of the percolator when glueing it back on later)
- place the glass cutter straight onto the glass
- gently apply force on it so you get a deeper cut while slowly turning it
- (practice on a normal glass before if you want to)
- don't panic - the glass cutter doesn't really cut the glass deep at all, more looks like a scratch

Step 2: Open Up the Bong

- Now carefully heat the small cut the glass cutter made. Use a jetflame
lighter (thicker glass) or a candle (thinner glass) for around 20-30
seconds.
- try to only heat the small cut
- then immediately cool the glass off with cold water
- the glass will crack after this. If it doesn't, try heating the cut longer or
you have a bong made of heat resistable glass.
- do this over and over again bit by bit until you have a nice crack going through and all the way around the glass
- you might have to re-cut some places
- after you have a crack around it it will either easily come apart or you have to gently knock it on an edge (of a wooden table)
- once apart, wash the inside out with hot water and dry the perc and the other two parts well with a hairdryer

Step 3: Fixing Your Percolator

- Firstly, take the epoxy and make an equally long line of each the epoxy and the hardener and mix it up well (you don't need very much)
- apply it to whatever you want to stick back together
- hold it in place for 5 minutes
- (if just one of the arms broke off you can either put it back on or block
the hole with epoxy and throw away the one arm)
- wait 10 minutes and apply another layer around the outside just to go sure it won't leak any water (only if your whole percolator broke off like in the pictures)

Step 4: Putting Everything Back Together

- Now, mix some more epoxy
- Find the exact position where the two parts were together before
- Apply it to both sides (not too much or it will flow out on the sides when
put together -> not so nice)
- push from the top so everything goes together tightly without air bubbles
- stabilize the position otherwise it moves slightly while drying and then you have edges
- it will be smokeable in 18-48 hours
- CONGRATS! You will have fixed your bong!

I fixed two bongs this way. Didn't find any tutorial with this method so I decided to share it with you!