How to shorten glass tubes

[Bernie Kopfer]

I have some 1” diameter glass vase tubes I would like to shorten from 8” to 6”. The commercial bottle cutting units do not work for such small diameters. Anybody have a method to do this?
Edit Note: why can’t I edit the title?

[John Keeton]

I would use the corner of a triangular file and score the line with a series of pull strokes - one stroke per spot with a light touch. It doesn’t need to be deep. It should snap after that with minimal effort. You can soften the edges with a torch.

[Robert Henrickson]

I have some 1” diameter glass vase tubes I would like to shorten from 8” to 6”. The commercial bottle cutting units do not work for such small diameters. Anybody have a method to do this?
Edit Note: why can’t I edit the title?

What John suggests may work. I did stained glass work for about 15 years, but never cut glass tubing nor did I cut bottles. That said, my glass cutting experience suggests that you need a *continuous* score around the tube (such as would be created by a bottle cutter) to get the break to run cleanly. I would suggest perhaps having the tube on rollers, so that you could hold a cutter (maybe even the edge of a file?) to the tube as it rotates to make a continuous score. The type of glass would also likely affect how easily/cleanly you might be able to score and break.

One of my takeaways from cutting glass was just how very sharp the edges are (like surgical steel)-- "where did those dark drips come from?" oops

[Lawrence Duckworth]

https://www.youtube.com/watch?v=XNC6NjCRc_k

I've heard of folks heating wire with a torch too

[Steven Cooper2]

You can cut it with an abrasive saw, or something like Dremel with a grinding wheel.

There are also glass tube cutters that are kind of like a spring loaded tube cutter as you just need to score around the edge. I've used those a few times, but I think I just gave up and used an abrasive wet saw at work. It was on quartz which is a little tougher than regular glass.

You might be able to score it with a regular tube cutter if you are very gentle or maybe not...

[roger wiegand]

In the lab we had glass tubing cutters, spring loaded devices that would trap the tube and score a line all the way around. An old lab glassblower (back when such things were common) showed me a trick to get a consistent fracture-- immediately after scoring you melt a very small ball of glass on the end of a rod or very small tubing (a glass Pasteur pipet works perfectly) and just touch it to the score line. The little thermal shock almost always gives a perfect break.

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[Richard Casey]

There are lots of YouTube videos on this subject. I bought some tube to put inside Banksia nuts for grinders and tried a few of the ideas. Used a knockoff Dremel to remove the sharp edges.
Rgds,
Richard.

[Eugene Dixon]

I use 1" glass sample bottles for my light houses. I cut them to length with a 10" HF wet saw using a diamond blade then square the ends with 220 sanding papers. The saw and blade are left overs from a bathroom remodel and some glass tiles. About an 20% loss rate but that may be operator error due to feed rate.

[Lawrence Duckworth]

if i were you, I use the ss .020 wire you've been using on your woodturnings, heat it up with a torch and loop it over the 1" tube like a choker, give it a ten count and shove the tube in a bucket of water and give it a snap. The whole process shouldnt take more than 15 minutes.


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[George Yetka]

Not often but a lot of boilers we have installed have sight glasses which are basically long tubes so you can see the water level. They have to be cut to size Im not sure of how big of a diameter it can go but its going to be far cheaper then the lab cutter

https://www.homedepot.com/p/Gauge-Glass-Cutter-WR1801000/202312944

[Bernie Kopfer]

Ordered a cheap glass tubing cutter off Amazon. Should work well enough a few times. Thank you all for the info.