Introduction: How to Cut Glass Bottles

Picture of How to Cut Glass Bottles

I show 3 methods to cut glass bottles. One with a string, one with a glass cutter, and one with a homemade bottle cutter. After a few tries cutting the bottles it becomes pretty easy to do. You can make drinking glasses, lamps, vases, and many other things from the cut bottles.

Step 1: Method #1

Picture of Method #1

The first method is with a string that is wrapped around the bottle then is soaked in a flammable liquid. The string is lit on fire while the bottle is being rotated, when the flame dies down the bottle is put into cold water. This causes the bottle to break where the rope was. Make sure you take all of the necessary safety precautions so you don’t get injured.

Step 2: Method #2

Picture of Method #2

The second method is to use a glass cutter and hold it on an object you want the height of the bottle to be cut at. The glass cutter is held in place and the bottle is spun around giving it a level score line. The score line on the bottle is then held over a flame while the bottle is rotated. After the bottle has heated up an ice cube is rubbed around the score line. After a while the bottle breaks apart.

Step 3: Method #3

Picture of Method #3

The third method uses a bottle cutter which can be bought or homemade. The bottle cutter holds the bottle in place while it is rotated around a glass cutter giving it an even score line. It can be adjusted depending on where you want the bottle to be cut at. The one I used was homemade. The same way is used to break the bottle apart that was used in the second method.

How I made the glass bottle cutter: (

Step 4: Watch the Video

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MadeByBarb (author)2017-03-12

I accomplished cutting even bigger jugs quite nicely. It takes a bit of practice to get the feel of working with glass. It doesn't take a huge temperature change/shock to force the break at the score line. Good luck, well worth trying...

deswiger (author)2016-09-19

Instead of the ice/fire, why can't you just tap it like you would any other glass you cut?

natis413 (author)deswiger2016-10-21

A glass item such as a bottle will break unevenly plate glass is a bit different it will essentially snap at the score line where as rounded glass sends the stress of the hit in all directions trust me found that out the hard way

deswiger (author)natis4132016-10-22

Intereseting, thanks.

PabloR72 (author)2016-09-19

I am going to try a mix of two of the methods. If I use a glass cutter and some support in order to score a horizontal line around the cutting line, but THEN tie the string with oil around the bottle right on top of the scored line, the fire should do its job, but the break should be smoother, along the scored line.

natis413 (author)PabloR722016-10-21

After 83 attempts and twelve stitches i can say with confidence it doesn't work unfortunately

surfer8 (author)2016-09-12

I need to cut some square bottles. Any suggestions or hints would be greatly appreciated.

kjmorley (author)surfer82016-09-18

Try filling it with oil to the point you want the cut to be, then drop in a piece of metal heated red hot. I used a sawed off carriage bolt. Make sure it's on a level surface, put it in something to contain the oil, wear your PPE.

Mooch07 (author)kjmorley2016-09-18

Would it be possible to put a thin layer of oil on top of water instead? Just hold the red hot metal on the oil layer?

jawtig (author)Mooch072016-10-02

Please don't try that. The heat into the water and oil could cause a volatile reaction. I played with oil and water mixture years back trying to anneal a piece of steal. It shot out droplets of hot oil all over the place. If you do attempt to use this process PLEASE be sure to have on a face shield, long sleves and gloves. Make sure to wear leather or wool or cotton. Synthetic materials will melt into you skin if the catch on fire.

kjmorley (author)Mooch072016-09-18

It should work with an inch or two of oil on the water. Maybe a thin layer would work. I think the trick would be to get the hot metal through the neck of the bottle and held at the right level. If you have a drill press, maybe you could use the chuck to lower it in vertically.

Robert61 (author)surfer82016-09-18

I believe a diamond saw blade will cut glass. If I needed to cut a square bottle, I would try that. You could put one in a table saw or better a tile saw, and then cut the glass like you would a tile. Be sure to wear goggles, and gloves in case it breaks funny. If you don't have one, you can rent them from some Home depots

DavidM443 (author)Robert612016-09-22

You MUST have a water bath saw to cut glass with a power tool. A wet tile cutter saw is fine.

DavidM443 (author)surfer82016-09-22

This you may have to do by hand. I would practice the general principle on round bottles first. Then on a "rolling" table or with a jig cut straight lines on the four sides and connect them "free-hand". Repeat this scoring a couple of times. Use your most useless bottle first. IT WILL GO WRONG SOMETIMES! Above all, be safe. My word glass is sharp!

SandiM10 (author)surfer82016-09-19

I cut my bottles n jars using the string, acetone and cold/ice water method, maybe that would work the see on square i don't see why it would work, after you make your line around bottle, you dip the string in the acetone and wrap it around on the line wearing gloves make sure you push the string onto bottle well, and drop into the water it just breaks off really easily, worth a try :)

dojers (author)SandiM102016-09-21

What do you do to make your line around the bottle? Do you use a glass cutter? Thanks and I apologize for the simple questions - I know it's not a stupid question - there's no such thing as a "stupid" question. I just means that person doesn't get that part and wants to know. That's what I tell all the people who ask me computer questions and say they're sorry that they are asking stupid questions. a little wordy there. I have a tendency to do that. :/

Nadine Sundown (author)surfer82016-09-18

The oil costs to much to make many cuts and it did not work for me at all anyway.

kjmorley (author)Nadine Sundown2016-09-18

If you're using the "blade and oil" method that's on youtube, I think that's a hoax. You'd need more thermal mass to get things hot. Used motor oil is free, and you can always reuse the oil.

Moem (author)surfer82016-09-14

I suggest a water-cooled tile saw.

JDanielMc (author)Moem2016-09-18

Tried that. No matter how slowly & meticulously we tried, some glass just would not "cooperate"!! We used a relatively high-end water-cooled saw with a new abrasive wheel.

dirk.medema (author)JDanielMc2016-09-18

The challenge with cutting glass isn't a matter of how fancy the saw is, or how careful the operator is. It is a matter of having the right blade on the saw. There are 2 types - 1 for cutting tile, and a 2nd for cutting glass. The glass blade is significantly more expensive, so not a std part of even most expensive tile saws.

surfer8 (author)Moem2016-09-14

Thanks for the reply. My neighbor has one. I think I'll borrow it and see what kind of destruction I can accomplish today.

JulieColl (author)surfer82016-09-18

I have a tile saw that I use all the time. It is awesome. If you are going to do lots of bottles invest in a diamond blade made specifically for cutting glass.

richpal (author)surfer82016-09-18

Me too...any suggestions would be appreciate....

محمودأ (author)2016-09-23

Wonderful !!!

DavidM443 (author)2016-09-22

A fourth method is to put the bottle in hot water and then cold water (and repeat if necessary) after the scoreline is made. I cut a couple hundred bottles this way in probably a total of ten hours. It is fast and easy, but uses a lot of the kitchen.

dojers (author)2016-09-21

With the 1st method - flaming string, then basin/sink of water, is there a chance that the whole bottle might explode or does it just get hot enough where the string is to make it "break" where the "hot spot" is? And do you immediately set the bottle in the water as soon as the fire is out or give it a couple of seconds. I'd like to give that a go but I'm a bit of a cautious person.....well.....not really but when it comes to glass I am :) Thanks for the instructable - pretty cool!

bobalbury (author)2016-09-21

Thanks, cool way to cut bottles.

JohnD316 (author)2016-09-19

Please do not use any power tools if you are inexperienced at this. Glass dust is very dangerous. Hand sand only wearing a facial surgical mask and goggles. Power sanders or cutters (Dremel etc.) will send glass shards everywhere. Be careful.

PabloR72 (author)2016-09-19

To smooth glass, use sandpaper. Glass is really soft and wears away quickly when rubbed with sand paper. The thing is, if it has sharp edges, (which it does, that's why you are sanding it!) it can cut through the sandpaper and cut your hand. I would recommend gluing the sandpaper to a little block of wood. Work slowly, and protect your hands and eyes.

ElviraE1 (author)2016-09-19

How do you smooth the roughness off the edges afte cutting?

IgnacioB1 (author)ElviraE12016-09-19


HerrS (author)2016-09-19

"Make sure you take all of the necessary safety precautions so you don’t get injured." And you have bare arms and no gloves:P

dbabinov (author)2016-09-19

Better make an instructable - how to make a bottle cutter yourself...

Pa1963 (author)2016-09-18

Back in the '70's there were a couple of bottle cutters for sale-one by Ronco/Popeil. The classrooms at my elementary school were chock-a-block with homemade "gifts" given to the teachers. Mostly made from Michelob beer bottles I think.

jsawyer (author)Pa19632016-09-18

I still have one the family bought in the 70's! They still sell them... on Amazon, of course...

As far as cutting a square bottle: As long as the score line goes all the way around, you can cut it. I use the hot water/ice water bath trick... Dunk it in the ice bath (have the score line at least an inch below the water line).. wait 20-30 seconds. Then go for the hot water.

This is where it gets tricky! If the hot water is too hot, you can crack the bottle where you don't want it. If it is too cool, nothing happens. I typically heat the water until the "making noise" phase... not yet boiling, leave the pot on low-medium heat and go for it.

(I make guitar slides out of wine bottles)

You can also do the tap from inside part, it might work more reliably. A lot depends on the bottle. Thicker bottles are harder to cut, but how the bottle is made may induce stress somewhere and it will just fail... Have a few bottles to work on...

bpark1000 (author)2016-09-18

After scoring the bottle all around, you can also use tiny hammer blows to start the crack. But the blows must come from the opposite side the score-line is on. Take a piece of #12 solid copper electric wire, and fasten a 1 oz fishing sinker or other heavy small object. Bend a curve into the wire so the sinker can be inserted into the bottle and strike behind the score-line, until you see a silver cast to the line, indicating the crack is started. Work around, tapping at the end of the crack to grow it around the bottle.

This is the same method used to cut flat-glass, except for the modification to get the hammer inside the bottle.

777arius777 (author)2016-09-18

Another method is to wrap a thin wire around the bottle and attach a 9v battery at each terminal 0f the battery end.The wire will get red hot then dunk the bottle in cold water and it should break along the wire. I saw this procedure on internet but did not try it. The thin 24 ga. wire can be stripped from an old extension cord

craftyincobalt (author)2016-09-18

Thank you for this nice tutorial.

TDWay (author)2016-09-18

just use mineral oil or baby oil. It lubericates the cutting wheel, reduces the chipping and wets the silica powder generated.

TonyVov (author)2016-09-18

Look also at oil on water version... I didn't try it yet but it seems like an interesting option.

Benstar (author)2016-09-18

The cracking off method is not mentioned here but is easy and safe.

pollywall (author)2016-09-18 Much prefer my method for comedy value. It also worked on square bottles ?

antonio.c.piresmesquita (author)2016-09-18

I done it with the string embedded with alcohol, but with the bottle standing up on a leveled surface and water up to the string level. Thicker glass needs thicker string. It woks , some glasses cut more neat than others. "THIS PROJECT IS NOT FOR KIDS" , unless supervised by an adult.

AnthonyF64 (author)2016-09-18

first things first - I really really dig your "machine" in the last two images. I'm also pleased you aren't a "burning string" evangelist.

May i suggest that you try another separation method? Boil water, and pour it into a jug large enough to submerse most of the bottle into. After scoring, dunk the bottle into the hot water, leave it for about 8 to seconds, then rotate the bottle - on the score mark area - under cold water running from the tap.

I've cut 1000's of bottles, and this system just worked for me.

obillo (author)2016-09-18

There is a commercially available bottle cutter--dating from the early days of Whole Earth Catalog and easily home-built once seen--that is based on Step 2 (rotate glass cutter around bottle). It will work on square bottles, though it's a bit tricky. The great thing about this cutter (which you can find with a little Googling, or at craft stores) is that it breaks the bottle apart by gentle tapping from the inside, using a long metal rod with bent end for tapping.

No matter what system you use, you have to smooth the cut edge for safety. Use fairly coarse emery cloth, rolled into a cylinder, and 'file' inside and outside edges at about same angle as when using your nail file.

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