quartz glas tube: how to shorten

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myID
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quartz glas tube: how to shorten

Post by myID »

Hi-

for my ion source I want to use a piece of quartz glas tube. How to cut it? Will it work like with a usual glas tubes?

Thanks
Roman
adrian.f.h
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Re: quartz glas tube: how to shorten

Post by adrian.f.h »

Hi,

I worked a little with glass-tubes (quartz and borosilicate) for several laser projects. As far as I experienced quartz can be cut the same way as borosilicate. At least with tubes of 1 cm diameter and a thickness of 2 mm. A hard-metal-blade-cutter works fine, at least for me.



Adrian
DaveC
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Re: quartz glas tube: how to shorten

Post by DaveC »

I've also had reasonably good results with borosilicate (Pyrex) tubing, with a score and snap approach. Usually had to use a diamond file on the ends afterward to get it completely square.

Quartz, though, we use a diamond bandsaw, purchased for that purpose. Quartz doesn't have the internal stresses that lead to a nice break.


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JohnCuthbert
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Re: quartz glas tube: how to shorten

Post by JohnCuthbert »

I have cut the stuff with a Dremmel with a diamond edged saw.
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Doug Coulter
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Re: quartz glas tube: how to shorten

Post by Doug Coulter »

I have found that the score and snap proceedure that works so nicely with pyrex is a very bad idea with quartz tubing in the sizes I've tried, from about 1/4" to about 1". It just shatters unevenly. I made a tool post grinder for my lathe that holds what amounts to a dremel tool with a diamond wheel on it, and use water as coolant as I feed that in to the tubing. This works fine, every single time and makes a nice end. The cooling is more important for pyrex than quartz, but a dribble of water on the quartz has the nice effect of keeping the fine silica dust out of the air....a good thing.

Nearly everything else I tried ended in disaster. I guess I'll have to post a picture of it so you can see what I'm talking about I plan to do this on my website soon anyway, as this and a nifty little propane/oxygen torch I also made are really nice tools for this kind of work. I also made a jig for straight line cuts in my milling machine, same idea -- use the machine's precision motion to get a nice careful gradual cutting action. I use the latter for cutting alumina plate (which is no small or easy thing to do).

These tools are crucial to making glass/quartz working easy and sure. Also nice are some pieces of graphite on heat insulating handles, as this doesn't stick to hot glass, and some various goggles. For quartz, the normal gas welders goggles are barely dark enough -- you have to get that stuff way white hot. For pyrex, I use some glassblowers glasses, which really rock, they are called something like didyium (a combo of rare earths) and only block the Na lines -- otherwise you can still see with them on in normal room light. Very cool thing to show people -- you can have a blinding yellow flame on your work, and seen through the glasses, that just disappears and you can see what you're doing again. Sweet.

With the toolpost grinder, you can also use things other than a diamond wheel to cut chamfers etc on pipe ends. This is better than fire polishing in many cases where you don't want to affect the pipe ID.

The torch is made up of a couple of cheapo needle valves from McMaster, and a wire welding tip which just happens to make a great gas torch tip too. They thread in so you can select sizes. This is good enough to do quartz, barely, and way better than you need for pyrex. I also use this for annealing, brazing, and so forth when it's not worth it to fire up the big acetylene one.

You can also sand quartz and pyrex on the belt sander - but that takes a good touch to do well.

In the last pic you can perhaps see a finished project made with this tech. It's a three layer quartz tubing HV feedthrough for my stuff, and it works great. I am testing another design just now, which is why that one isn't in use.

With a small stock of quartz/glass and these tools you can save so much money on vacuum work it's not funny. Way worth it to tool up and make your own, easy to fix/replace stuff than depend on the vendors or ebay for these crucial parts. And cheaper.
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lampet
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Re: quartz glas tube: how to shorten

Post by lampet »

I 3D printed a jig so that I could score a 35mm diameter quartz glass immersion heating tube with a standard glass cutter. The jig worked fine but the glass would not break with heat shock. I'm heating it along the score line with a small gas torch and then immersing it in ice water.

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Finn Hammer
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Re: quartz glas tube: how to shorten

Post by Finn Hammer »

Lampet,
Your first post should not be in this forum, but in the "Please introduce yourself" forum, and in this post you should demonstrate, that you have read the rules, which cleally states, that you must use your full name instead of just lampet.
You have been searching the archives, since you dig up 10 years old posts, that is a good thing.
This post also gives valuable information, from Dough Coultier, and that advice is worth following.
The reson your method does not work with quartz glass, as it would have with bottles and marmelade jars is, that quartz glass has an extremely low coefficient of expansion, and therefore builds up neglectible internal tensions due to uneven heating.
The lathe/dremel solution is a better one.

Cheers, Finn Hammer
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