Hey, So I have this empty bottle with a really nice thick bottom.

Perhaps look up the method used to create cups from bottles. Will have to sand it after but should work. Unless you want to cut it with a diamond saw.

File: cutting bottles with string.jpg (46KB, 476x518px)

46KB, 476x518px

I've never actually tried pic related, but it seems like a fairly accessible approach for us normies without specialized equipment.

Rotary tool, diamond cutting discs.

>>1123284
1 Score a line around the bottle
2 place bottle into pan of boiling water for five minutes
3 Remove bottle from boiling water and place into ice water
4 repeat if needed

>>1123293
Not OP but hypothetically would this method work for cutting circles out of a sheet of glass? I want to make some solar-viewing goggles out of welder's glass.

>>1123308
Just get welding goggles.

>>1123319
Whoops, am I not on the /diy/ board?

>>1123284
Fyi no one has answered the question of OP, asking about how to cut out bottom, not cut off. string method wont work.

I have a similar project, cutting down an irregular vase that had a piece chip off (so cutting off the broken top 3"), and the best I've been able to come up with is basically this http://www.instructables.com/id/Want-to-cut-wine-bottles-Build-this-jig/

plus the thermal water shock method.

>>1123321
Some things are practical to DIY, and some are not. If you're interested in results rather than doing things yourself for fun, inexpensive PPE is one of those things that's usually better to buy.
https://www.amazon.com/Hobart-770094-Welding-Oxy-Acetylene-Goggle/dp/B0017Z04S0/ref=sr_1_39?ie=UTF8
https://www.amazon.com/Weldcote-Metals-Shade-Filter-Lens/dp/B005BCUOH6/ref=sr_1_2?ie=UTF8

>>1123308
non autodarkening welding hoods are dirt cheap, just get one of those

>>1123308
And incidentally, you can buy round welding glass lenses for goggles that fit them, both comparable in price to the previous links.

>>1123284

tie a string soaked in rubbing alcohol where you want it to cut. light the string on fire and wait 30 or so seconds. then run cold water over where the string was and it will cause it to crack due to thermal shock

now your left with sharp edges, don't be a pleb and sand it smooth which will look like shit, fire polish it like pros do.

you want a small torch, a refillable butane torch works great, propane for soldering pipes is too big and you run the risk of warping the hell out of it.

lay the glass on its side bracing it so it can't move and move the flame from the butane torch around the sharp edge where it broke from thermal shock. just keep moving the flame around the glass in a circle

the glass will glow red, when the sharp rim starts to glow almost white hot stop. you only want 1mm (.0040") or so to glow white hot, if you have dark sun glases you can see the sharp edge melt and bead up to form a nice smooth edge.

now let the glass cool on its own.

>>1123293
thats a great way to end up with shattered glass everywhere, not to mention the shards will be fucking hot, its heating to much of an area.

>>1123308
you want at least shade 14, any less and you'll fuck your eyes up. just use a glass cutter to score and break it into what shape you want. just have the sharp edges covered in whatever frame you plan on using. they already make welding goggles, just get shade 14 lenses for it, its not that expensive. you could make them yourself, but depending on what tools and materials you have to buy for the project it might be cheaper just to buy welding goggles. its your call if you want to spend more on something while not looking as nice and have others view you as an idiot.

Fill it with water and smack the top. The bottom should separate. It's called water hammer

>>1124460
Came to post this. I do this all the time with empty beer bottles.
>You motherfucker

>>1124522
dubs never lies

>>1123293

Nope! I've tried it. It's fussy. Much breakage. It's way easier to use a rotary tool and a diamond disc.

>>1123284
diamond tile saw

>>1123287
>>1124382
>string method

Don't do this. It is FUCKING TERRIBLE.

Watch this and do this instead:

https://www.youtube.com/watch?v=sFXngPx3w3M

File: Preparing_for_the_Technician.gif (829KB, 500x281px) Image search: [Google]

829KB, 500x281px

>nice thick bottom

Good taste, OP

Like if you thought it was one of those clear Fleshlights at first.