Cutting glass bottle

[wildwood]

I would like to cut the bottom third of a glass bottle, so that I'm left with a dish. Tried it with a glass-cutter, but that doesn't work. I vaguely remember reading something yonks ago about tying a string around the bottle which is first soaked in some volatile liqiud, and then set fire to, thus cracking the bottle.
I would appreciate it if someone could tell me what liquid to use so that I won't blow myself up.

[sft42]

Parafin...I used this very technique to make a bottleneck slide from a wine bottle one time as a memento of a fum night.....simply dip the (Strong) thread into the parafin and tie tightly round the part of the bottle you want and leave for a good few hours.....then you can either, depending on the quality of the glass, simply break it apart or set fire to the string.

[incitatus]

if using this method stand very well back as the chances of the bottle shattering violently are high. professionals would either use a diamond bladed saw ( not as expensive as you would think) or the glassblowers method which is to score a line with a glass cutter all the way ound then touch it with a red hot peice of metal-while wearing gloves and safety glasses. Always polish down the glass edges with a whetstone afterwards.

[paulz]

wildwood - according to Jeeves [and my dad who did this in WW2, put oil into the bottle, up to the level [depth of dish] you require. Heat up a bar of metal till it's red hot, dip into the bottle and it should crack around the top of the oil. You used to be able to buy a gadget in Exchange & Mart, that scored round the outside, then you had an angled metal rod that you tapped around the score line to snap it. Then as incitatus says use a whetstone or I found wet & dry on an electric sander moistened with soapy water, decreasing the grit size, effective and quicker. Be careful as electricity & water don't mix very well - you only need it moist

[wildwood]

Thanks for your tips everyone, much appreciated.
Will have a go at the parafin. A bit apprehensive about the red hot metal method though.

[fraserjim]

Do the red hot poker thing use engine oil it works every time ive actually cut a milk bottle into 12 rings

[Jenny Tools]

I can confirm I have heard people getting good results from the red hot poker method although I have not tried it myself. My only advice is to make sure you use safety glasses and gloves what ever method you use.