Wednesday, March 17, 2010

Hot wire glass bottle cutter

In a surge of boredom I did a search for glass bottle cutting. I found this page. That shows a hot-wire bottle cutter. I cloned the design. It's basically a laminate board with a couple of screws and nuts, a spring and some NiChrome wire.

I used an old AT PSU to heat up the wire. The 5v rail is loaded with a 20-something ohm 10W resistor that can't be seen on the photo. (A load on 5V is needed to stabilize the 12V rail)

It works reasonably well.

Precision depends on how straight you can get the wire around the bottle without shorting it. The rim still needs a lot of tedious work to complete a viable drinking glass which I'm definitely too lazy to do. But it was worth the 5 minutes it took to build it.

I might come up with a rim auto-sanding contraption in the future.


  1. Can you draw a shematic for 5V rails with resistors?

    -----------[10W]---> (-)
    [ 5V ]
    -----------[10W]---> (+)

    That is correct?

  2. You need to add some kind of load to the 5V rail. A big resistor will work. You just hook it up between 5V and GND. (+)--[ 10Ohm 10W ]--(-)
    It will get hot, this is normal. You may want to select a resistance value to make sure it doesn't get too hot and set something on fire and/or you may want to cool it.
    See here for more info:

    If you have some really old HDD or something you may be able to use that instead.


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