I know there are already quite a few great bottle cutting instructables but I find this technique to be the fastest, and in my expirience the cleanest and easiest way to cut bottles. My project was to make a set of drinking glasses from old pepsi bottles that I had lying around, but you can use this technique for whatever project you like.
Step 1: Tools
All you really need for this is a simple glass cutter you pick up from a hardware store and a propane torch with a relatively fine tip. It may work with something else like a lighter, candle, larger torch etc. but I have yet to try those as my little benzomatic pencil torch has worked so well. My preferred way to do this also involves a lathe with a very slow speed but it can be avoided as I show later in the instructable. All you really need is some way to rotate a bottle at a relatively slow controlled speed, Ive done this on a potters wheel also but you could easily rig something up with a geared motor from a toy car, its only needs low torque.
Step 2: Nick
This is what makes this method so much easier, you dont need some jig to cut around the edge of a bottle perfectly all you need is a to make a little (like 1/8") nick with the glass cutter that would follow around the circumference of the bottle. It should be a decent nick with quite a bit of pressure applied to the cutter.
Step 3: Spin it (lathe method)
All you need to do now is find a way to rotate the bottle slowly, the way I like to do it is use my sherline lathe and set the variable speed to very low, I put a pencil in the tail stock so everything doesnt just fall down when the bottle breaks. Then you simply light your torch and hold in place over the nick while the bottle spins, after about a minute depending on the thickness of the glass there be a cracking noise and a line will appear all the way along the bottle. The bottle sometimes but wont always split in half, sometimes you just have snap it with your hands, be careful the edges will be sharp. As always be carefully the is fire, a spinning lathe, and the potential for broken glass. At the end of my video you hear a clicking noise its not from the glass breaking its because my chuck loosened and the bottle was falling between jaws, I would recommend wrapping a rubber band around the base of your bottle so you can get a better grip.
The crack is usually perfectly clean only requiring light sanding to smooth out sharp corners but sometimes you might get a slight bump the needs a bit more sanding, I usually just do another bottle because its so easy.
The crack is usually perfectly clean only requiring light sanding to smooth out sharp corners but sometimes you might get a slight bump the needs a bit more sanding, I usually just do another bottle because its so easy.
Step 4: Spin it (string method)
This is just one way to do this without a lathe, there are much easier/safer ways but this should give you an idea. You need something that will fit over the top or bottom of your bottle that you can attach string to. You could always just duct tape string directly to you bottle but this is more repeatable. I found that a water bottle cap was a good fit so I punched a hole in the bottom and tied some thin string to a piece of wood and taped that inside the cap. I then taped the cap to bottle and tied the string to my ceiling. Then I simply spun the bottle up to build up rotation in the string, I regulated the speed by taping it with my finger. Make sure you have something directly below the bottle so it doesnt fall too far and break.
Step 5: Enjoy
Do whatever you want with some cleanly cut bottles, I sanded my rims and made a nice set of pretty neat looking drinking glasses, the painted on graphics on the pepsi bottle looks cool and lasts well.
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I'll test your method.
Thanx
There's so many different technique/method on the web, and yours is very simple and i have a pen torch and a glass cutter is very cheap around here.. :)
I'm wondering about the success ratio of your method, and if different bottles have different success.. I have some pretty exotic bottles that i want to cut for a project but i'm really afraid to screw up.. and i cant just try it out on them since i only have a couple..
Did you manage to try Jor2daje's method, asegade?
if yes, would you care to share your experience?
I'm also wondering about the nick vs the scoring all-around..
I think the nick is better, it gives a start point for the crack and then the crack will run straighter and smoother.
The all-around-scoring would be rougher. all of the tiny fractures along the score-line might give way for the crack to jump out of line and create a rough crack..
What do you guys think?
thanks again!
www.Greenpowerscience.com Water cutting a bottle cleaner and you can reseal the bottles and make vacuum tubes
Pretty cool
Nice Ible
i suppose liquid wasn't the best word i could have chossen but i don't know the real SCIENTIFICT term for theis type of matieral. i may be 15 but i know quite abit about science.
This disc was inevitably thicker near the centre and once cut down into panes gave sheets of uneven thickness.
Anyone then using this glass would (probably) tend to put the thicker due at the bottom if only because it 'feels right' that way.
I have seen a method that scores the bottle the whole way around, then uses hot water and cold water that does the same thing but on a smaller scale yet. The result was a bottle that after it was cut, the seam when held together would still hold water
u s rao
Dictionary words can't be trademarked.
That's why everything is spelled wrong in advertising.
Internal fractures can occur in any glass. Usually from being improperly cooled. There is a "Wiley Coyote" effect when there are internal fractures. The Krinkle- Krinkle effect!
If the glass does not break cleanly - stop. Look carefully - tap lightly with ball end of the scorer shown in this artical. Turn glass at different angels in light. There is a great possibility that there are fractures you may not see right away. Note the Krinkle effect mentioned above.
I Would Not TrustbA Glass Not Cleanly Broken!
Do not try to polish edges with a torch. Glass "polishes" at 1250 degrees F. There will be too great a difference in temperatures.
Have fun!
Been there, Done that, have the T-shirt and have made living cutting glass
Glass having a very low resistance to tensile stresses, it always starts to break from the surface most subject to stresses of this kind, whenever that surface has the slightest imperfection.
If you heat a bottle, or any cylindrical shape for that matter, the external surface, being larger than the internal one, expands more, so becoming subject to a greater tensile stress than the surface on the inside the bottle. If you then score the outside nsurface the bottle will break. This is mainly due to the added tension induced by heating and expanding.
One may "score" a glass bottle on the outside without breaking it - you may, for example, drill a bottle to make way to an electric wire for mounting a lamp - provided it is not subject to the extra tensions induced by heating.
(most of the time glass is not actually cut, but scored whith a small wheel, usually made of tungsten carbide. Then it is slightly bent to the side opposite the scoring and, the scored surface becoming subject to a tensile stress, the glass breaks starting from the score)
It is true all glasses have surface - and internal - stresses, unless perfectly annealed under very controlled conditions.
In the case of bottles and similarly shaped pieces, the tensions arise mostly from the shape itself, which makes for uneven cooling. But in many cases bottles can be cut without shattering.
In flat so called "annealed" glass, a very slight amount of controlled tensions is induced on purpose during the cooling process to ease breakage on cutting.
In the case of tempered glass, strong compressive stresses on the surfaces - balanced by equally strong tensile stresses in the core - are induced on purpose. Glass is highly resistant to compression, and as it always breaks from the surface subject to a tensile stress, this actually makes the piece work as, for example, a pre-stressed concrete beam. At a price - if you nick the surface of a tempered glass, the equilibrium between the compressive and tensile stresses is broken and the glass literally explodes. That is why tempered glass can not be cut in any way.
Sorry, I digress...
I pour hot engine oil from the car into the bottle to the level where you wanna cut. Then let it cool down and easily hit it and a perfect one will come out. Oh, by the way, if you like pranks, go to http://www.instructables.com/id/The-Easiest-PC-Prank-anywhere-anytime-if-You-Hav/
http://www.instructables.com/id/Easiest-Coolest-Most-Effective-Stealthiest-Fun/
Please, try it and leave a comment...
Also, could you use a carbide tool in the lathe to get the nice even score line?
This induces the bottle to shear at that point espeially if it has a scratched line in the glass.
Worth a try?
GF
A pane of glass placed vertically will not become thicker at the bottom no matter how long you wait for that to happen.
Glass tempering is essentially a physical process, where the "tempered" properties are achieved by inducing compressive stresses on the surface (in return for tensile stresses in the core). You nick the surfece, the stress equilibrium is cancelled, the glass shatters.
By contrast, metal tempering is essentially a chemical process, where the crystalline structure of the material is modified to get the desired properties. It is not stresses you are looking for here - in fact, they are generally undesirable - it is a different chemical and cristalline structure.
Maybe needless to say, I have worked in both fields...