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zoas23
01-25-2013, 06:50 AM
Anyone has experience cutting large glass tubes? (pyrex)

I am trying to cut one of these:

http://www.bimarloga.com.ar/site/components/com_virtuemart/show_image_in_imgtag.php?filename=43bcdd70d683f5dc 86b93e34093b255f.gif&newxsize=150&newysize=261&fileout=

So far I managed to break 3 of them... several times! (I probably failed 3 times with each one).

I am good cutting the "small tubes".

My tool is a triangular glass cutter:
http://www.ferreterialaherramienta.com/1672-2470-large/lima-fina-200-x-105-156-mm-8-pulg-triangular-4005-bellota.jpg

Why am I trying to cut one of these tubes?
Because, believe it or not, glass tubes with both ends "open" don't seem to be available in my country and I need one to make a home-made Vigreux Column... the Graduated cylinders cost $25 (local money), the real Vigreux costs $700 (local money) -I paid $400 for a very good one litter heating mantle, so $700 is quite expensive.

I've been reading a lot of tutorials about cutting large glass tubes... I saw videos on youtube... I specially likes this one:


http://www.youtube.com/watch?v=MeZ59fg6c7E

(the image trembles, but the guy seems to know what he's doing... except that the "trick" doesn't work at all when I try to emulate it... the tube he cuts has mostly the same size than the tubes I am working with).

I've already tried everything and all the methods I found in tutorials.
i.e, cutting one half of the tube and then breaking it.
i.e, cutting the whole circle and then breaking the tube.
i.e, cutting the whole circle and then heating the tube and trying to cut it whilst it is hot.
i.e, cutting the whole circle, then heating the tube and then placing the tube in cold water.
i.e, cutting very deep...
i.e, making the cut quite shallow...

I've also spent some 7 or 8 hours cutting glass and all I have is broken glasses.

So far everything has failed... anyone has experience with cutting these LARGE tubes?
Any tips you can share? (the guy in the video is impressive, I have to admit, but his trick doesn't seem to work at my house!).

Ghislain
01-25-2013, 10:26 AM
Zoas

I have never cut glass tubes, but I have an idea.

Try an electric tile cutter...these use a diamond tipped cutting wheel.

http://t1.gstatic.com/images?q=tbn:ANd9GcRTrvv4OzbCFfwxd4-zW_x2xzrIHXHB9uBWhnDZlaDnDryUe6bKxA

Tape the tube where you want to make the cut to stop vibration cracking it.

These type of cutters can be picked up quite cheaply, but I'm sure you know someone who has one you could
borrow.

I wouldnt try pushing it straight through, but rotate it on the blade.

Just a thought...

Ghislain

zoas23
01-25-2013, 12:39 PM
Thanks!
BTW: I've just found a glass factory/provider that sells the tubes (borosylicate) just as I want them... it's 90 minutes by car... but I'll go there.
Quite strange, because I live some blocks away from the street in which mostly ALL the lab providers are (next to the Chemistry university)... but none of the shops had these tubes, nor they have ever seen them or even suspected that they exist.
And then I found a strange shop located in the middle of nowhere that has them.

I think I won't be cutting.

zoas23
01-25-2013, 05:36 PM
Gosh... I went to the glass shop and the cost of the glass tube is $700... !!! Never expected that.
So I didn't purchase it... it didn't make much sense to create a home-made vigreux that costs exactly the same than a "real" one.

The glass cutters here are a bit expensive (because they are imported), so I decided to give it a try with other stuff:

I bought two different things to experiment with:

1: an Aluminium tube which is easy to cut (I am going to use it for quite basic spagirics and working with temperatures that won't go further than 150). Do you think it is a good idea to use a metalic tube? Or I should try to avoid metals?
2. three pots made of normal glass (nor pyrex)... Do you think it would resist the heat? (I am not working with very extreme heat)... I am not working with vacuum or sealed vessels either... so there are no pressure issues, only heat.

If it's not a good idea, then I'll try to find someone who has the tool you suggested.

Ghislain
01-25-2013, 07:03 PM
Zoas

I wouldn't use Aluminium for anything you intend to digest...
just boil some red cabbage in an Aluminium pan and you will
see it turn blue.

Also there are links to Aluminium and Alzheimer's (http://en.wikipedia.org/wiki/Aluminium#Health_concerns)

Good luck.

Ghislain

thoth
01-25-2013, 09:10 PM
I saw something on another forum (which is now in the ether ...), a link on cutting glass using a simple scoring and then heat and cold. I forget the guys website, but it is similar to this link
http://www.youtube.com/watch?v=AOutjiQFN_s

BTW i saw recently in IKEA glass just like measuring cylinders but without the markings - used for small flowers.
I wonder if a florescent light with ends pulled off could be useful also

zoas23
01-25-2013, 11:35 PM
Zoas
I wouldn't use Aluminium for anything you intend to digest...
just boil some red cabbage in an Aluminium pan and you will
see it turn blue.
Also there are links to Aluminium and Alzheimer's (http://en.wikipedia.org/wiki/Aluminium#Health_concerns)
Good luck.
Ghislain

Thanks again for the good advice!


I saw something on another forum (which is now in the ether ...), a link on cutting glass using a simple scoring and then heat and cold. I forget the guys website, but it is similar to this link
http://www.youtube.com/watch?v=AOutjiQFN_s

BTW i saw recently in IKEA glass just like measuring cylinders but without the markings - used for small flowers.
I wonder if a florescent light with ends pulled off could be useful also

Thanks for the link!
I will give it a try with the Pyrex glasss again next week (I won't find the materials during the weekend). Even though I've mostly done something very similar to what they show there, except that I did cut the whole line by hand only and using the file that is normaly used for cutting lab tubes... and managed to get a verry deep line, but then the cracks in the tube didn't want to follow the line at all.

Meanwhile, I will try with other even more simple simple methods that work fine (at least in youtube!) for cutting glass... methods that did not work for pyrex (God knows I've tried and tried!), but in theory they are perfect for normal glass. And I'll see if normal glass can stand the heat without breaking (I'll probably do a couple of simple tap water distillations and see if the glass likes it or if it breaks down).

hincestifr
02-13-2013, 11:52 PM
Hello Zoas,

Check this method...www.jaderbomb.com/2012/06/14/how-to-cut-glass/ i think it will help.

zoas23
02-14-2013, 03:42 PM
Hello Zoas,

Check this method...www.jaderbomb.com/2012/06/14/how-to-cut-glass/ i think it will help.

Thanks! I've already done it and failed more than a few times... but they said that practice and persistence is the key of it all.

I have plenty of glass bottles, so I will practie again and again with them till one of them finally gets a clean cut. It's not a problem to destroy several bottles in the process... it's not that I need all the ones I have.

Thanks! :)