How to cut glass safely?

I just need a small vertical part of a delivery tube, and I have a bit but it is broken at the bottom...

Just wondering if I could use this and cut it down to size for it to be used?
 

ajmc98

Don't lick, smell or touch it and you won't die.
Use a small triangular file to mark the correct length round the circumference and snap inside a tea towel, does require polishing after and does need quite deep filing to get a clean snap.
 
Use a small triangular file to mark the correct length round the circumference and snap inside a tea towel, does require polishing after and does need quite deep filing to get a clean snap.
I literally need about 1cm* off one end, most likely less than this, as the breakage is at the bend of the delivery tube. The piece of glass I am working with is just over 5cm.
 

ajmc98

Don't lick, smell or touch it and you won't die.
I literally need about 1cm* off one end, most likely less than this, as the breakage is at the bend of the delivery tube. The piece of glass I am working with is just over 5cm.
Yeah you may struggle trying to get that much off with the method, nominate DT? or as above a glass cutter?

Or if its less than a cm maybe sand it down?
 
I literally need about 1cm* off one end, most likely less than this, as the breakage is at the bend of the delivery tube. The piece of glass I am working with is just over 5cm.
If the whole piece was 5cm and I needed to cut 1cm off, I'd put it in the glass bin and cut a new piece.
 
I use a file , only one score, not all the way round and snap it away from me. It's really difficult to cut a short piece off because you haven't got the leverage, as Alice says cut a new piece.
 
I'm intrigued, how?
I think it involves scoring the tube all the way round and then getting an assistant to hold the tube at both ends while you wrap a length of string around the diameter of the tube on top of the scored line and then pull the string back and forth to generate heat. When it gets hot enough, the temp difference between the glass at the scored line and the glass in the rest of the tube will cause the tube to break around the scored line. This method is generally used for larger diameter glass tubes.
 
I think it involves scoring the tube all the way round and then getting an assistant to hold the tube at both ends while you wrap a length of string around the diameter of the tube on top of the scored line and then pull the string back and forth to generate heat. When it gets hot enough, the temp difference between the glass at the scored line and the glass in the rest of the tube will cause the tube to break around the scored line. This method is generally used for larger diameter glass tubes.
Would this work with face mask elastic? :rolleyes:
 
I think it involves scoring the tube all the way round and then getting an assistant to hold the tube at both ends while you wrap a length of string around the diameter of the tube on top of the scored line and then pull the string back and forth to generate heat. When it gets hot enough, the temp difference between the glass at the scored line and the glass in the rest of the tube will cause the tube to break around the scored line. This method is generally used for larger diameter glass tubes.
Yep that's it. Although he touched it with a wet finger.
 
If you have got a fine gauze, we have some without the heat proof white circle in the middle, you might be ale to file the tube down using the gauze as the file. Might need a polish in the bunsen flame after just to smooth off any rough edges.
 
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