Cutting glass - Hardened, Pyrex, Quartz and plain old glass

[decoy]

Hi guys
Just finished reading a few posts relating to glass cutting and shaping.
Hope this triggers some ideas for your next build.

I have a hobby CNC router, I have successfully cut into shapes and engraved hardened glass using a 3mm spear shaped tungsten carbide drill, plunging .5mm at a time at 15000rpm

tile-glass-drill-bit-3mm-23015-p.jpg (8.21 KiB) Viewed 3690 times

Also I have cut hardened glass sheets using these new Lenox diamond angle grinder cut off wheels.
These cut like a hot knife through butter, just go easy and feed slowly to avoid chipping.
They also work great on metal, below is a amazon link.
https://www.amazon.com/Lenox-Tools-1972 ... op?ie=UTF8

[cranky]

NEVER ATTEMPT TO CUT OR ENGRAVE TEMPERED GLASS!!! Tempered glass is under tension and should not be cut without being annealed.

[cob]

I have cut my share of glass however the only attempt at cutting tempered glass was not with a diamond wheel

and left me with a workbench covered with very small pieces of broken glass making crackley noises.

[decoy]

I stand corrected, I should have said hardened not tempered glass, I have corrected my original post and title.
I have not cut or engraved tempered glass.

Please accept my apologies if I have mislead anyone..

[cob]

no apology necessary I just thought I was learning something new, but I been in trouble

for thinking before, like thinking I could cut tempered glass. my boss told me ain't no way,

but I tried anyway. the thought was it's to big and worthless to me at this size. so what do I have to loose?

on a side note old glass is the worst to attempt to cut clean.

[NZChris]

A good friend of mine who took up using grinding and drilling machinery for making beautiful stained glass work passed away not long after she was diagnosed with lung cancer. I don't know if it was related, but I was relieved I'd never gotten into that side of the art.

Keep water on the work and wear a mask.

[decoy]

I made a little pool wall using packing tape and just place a small puddle of water around the cutter using a large syringe.
most dont bother with water.

there are new tungsten carbide drills cutters engravers saws that are being released, it is amazing what is possible with them, I watched an add for new design tungsten carbide 12" circular saw blades cutting metal beams.

https://www.youtube.com/watch?v=rfGxQRX9qJA

[cranky]

I stand corrected, I should have said hardened not tempered glass, I have corrected my original post and title.
I have not cut or engraved tempered glass.

Please accept my apologies if I have mislead anyone..

A lot of people come to this website not understanding anything about glass especially tempered glass. Some have tried to make sight glasses out of it and have successfully cut it only to have it later explode on them which would be downright dangerous as a sight glass. With many things we need to be careful what we call things, but you already know that. You will see that I have now altered my original post because once you altered yours mine didn't make a lot of sense.

I think doing things with glass is cool, after all I have 2 glass columns. I used to play with glass a lot and do a lot of stained glass when I was in Kansas. I made a grape arbor window for our kitchen door, which my wife always regretted not taking with us and I was working on a huge peacock window for our office but I never finished it Some day I will recreate them both when we get to our forever house.

I also have bought some pilsner and wine glasses because I sometimes give away cider and wine and would like to etch them with my own logo to go with them.

[cob]

I had a piece of glass from a halogen lamp at room temperature disintegrate in my hand as I put it in tepid water to wash it.

[cranky]

I had a piece of glass from a halogen lamp at room temperature disintegrate in my hand as I put it in tepid water to wash it.

Funny how glass can do that. That reminds me of one time I had a late 1800s true end of the day glass cane sitting on a shelf suddenly develop a 2 inch crack for no reason. Luckily that was back when I had all my glass working stuff and the cane was long enough to be cut down by 2 inches.

[decoy]

I forgot I had a few pics.
I might have to do thread on CNC routers, they are great for cutting basically anything that needs lots of holes slots etc like shotgun condenser ends and bubble or sieve plates.

[DetroitDIY]

I made a grape arbor window for our kitchen door, which my wife always regretted not taking with us and I was working on a huge peacock window for our office but I never finished it Some day I will recreate them both when we get to our forever house.

Ahh... The forever house. I didn't think I was in mine until the 5th or 6th major built-in where my wife said 'We can never leave now.' I'm about half way through yet another one of those built-ins at the moment.

As far as glass cutting goes, I had just learned how to do laser etching on glass with a rotary attachment when the Detroit TechShop closed a few years back. Too bad. I had visions of drinking glasses and beverage bottles with my own designs on them. Definitely fun stuff. And thanks for the tempered glass warning Cranky. Not that I expect I would have ever tried it, but I didn't know.

[DetroitDIY]

... And that looks amazing Decoy. Is that your own little CNC?

[decoy]

Yes it is, these are only around the $800 AU on ebay, its a 6040 cnc router.

Regrets, but easy upgrade to >
Brushless water cooled VFD motor 1.5kw
USB interface instead of parallel port.
Wet Bed.

I will do a new thread tonight/tomorrow, specifically for CNC Routers and 3D printers, will cover what I have learnt and what I would do the second time around buying another unit.
But these are a hobbyists must have if you like making stuff.

[cranky]

I'd really like a CNC router and 3D printer but being a cheap bastard have to settle for a Dremel tool and pocket knife

[Yummyrum]

I'd really like a CNC router and 3D printer but being a cheap bastard have to settle for a Dremel tool and pocket knife

Got a have a steady hand there Cranky , them Dremels have a mind of their own

[cranky]

I'd really like a CNC router and 3D printer but being a cheap bastard have to settle for a Dremel tool and pocket knife

Got a have a steady hand there Cranky , them Dremels have a mind of their own

You think Dremels have a mind of their own, I've been working on a tailgate for my truck and had to cut 3/8" wide square ended slotted holes with a die grinder and rotary file, a Demel ain't nothing compared to a die grinder. I've actually done a lot of glass work with a Demel, sometimes you get a valuable piece that's damaged and need to make it perfect again and a Dremel with the right attachments can do wonders.

[zapata]

Soooo....
What if I wanted to cut a pyrex tube lengthwise? It's for a different hobby, but picture trying to cut a crystal dragon style site glass in half or thirds around the perimeter.
I have you typical handy collection of tools... dremels, angle grinders, a small cut off saw that uses grinder cut off discs etc. But what to use for the cutting, and suggestions for water etc?

[cranky]

Soooo....
What if I wanted to cut a pyrex tube lengthwise? It's for a different hobby, but picture trying to cut a crystal dragon style site glass in half or thirds around the perimeter.
I have you typical handy collection of tools... dremels, angle grinders, a small cut off saw that uses grinder cut off discs etc. But what to use for the cutting, and suggestions for water etc?

I've been avoiding this hoping someone else would answer first but I guess I will give it a go. If it were me I would make sort of guide for a glass cutter and use a good oil filled glass cutter. Alternatively I might consider something like a tile saw with a very good diamond blade. A lot of tile saws don't run smoothly and the blades they come with are very hard on glass so cheap ones won't work.

[NZChris]

What if I wanted to cut a pyrex tube lengthwise?

Buy much more tube than you need, especially if you want to finish with a long length of channel and it's a long walk to the shop to get more.

Scribe both sides as Cranky suggested.

Tap it from the inside with something hard and sharp to get a crack started.

Propagate the crack up the tube by tapping just in front of it.

Repeat to do the other side.

I wish you good luck.

[zapata]

Ya see, that's why I haven't bothered yet. I just wanna be able to hit it with something like that angle grinder disc linked above. I trust myself with an angle grinder... This scoring and tapping business seems like a controlled shattering to me, and I have no faith in it actually being controlled!

[NZChris]

Shattering happens when it all goes wrong

Controlling where a crack runs is a skill that's not all that difficult to learn. A bit of practice and bin for the less successful attempts is all it should take unless you want to make the near impossible from a single piece of expensive glass. What are the dimensions of this piece you want?

[zapata]

Well I'm prototyping, so I'll likely go through several variations. Well, I will be prototyping if I ever get around to starting

Some applications could probably literally be cut from crystal dragon style sight glasses, though I'm not too sure on their exact ID, wall thickness etc. So say 4-6" long, 3-4"ID, but split into semi-circles. I might pick one up for testing next time I order something from a supplier.

I do occasionally stumble across long tubes cheap, so ideally I'd be able to cut big pieces. I get it's a skill I just need to pick up. A few glass experiments years ago of someone saying, just do this, which resulted in shards convinced me that working with glass is some arcane mystery that nobody really understands. Time to get over that I suppose, once upon a time soldering and distilling were mystery arts as well

[NZChris]

So say 4-6" long, 3-4"ID, but split into semi-circles.

That should be a piece of cake with nothing more than a cheap glass cutter.

[decoy]

I tried to cut glass normal and hardened with various diamond blades it took to long
The problem with cheap blades is there not perfectly centered and or balanced, when used it causes them to bounce or vibrate on the job, and then the uncontrolled crack happens.
When using diamond blades get good centered and balanced ones, and you need a guide that can be lowered in small increments.

With a CNC and or Dremel etc.. you can use tungsten carbide bits to cut shapes, the less the cutter engages the work the less vibration.
I stated with the cheap spear type drill and it work well.
It basically engraves/carves its way through, the added benefit of using CNC is the plunge and feed control for profile cutting.

[zapata]

Decoy, what about that disc you linked above? How would that work, just in a normal angle grinder? Would it need some kind of water bath / jet thingy? I could build a jig for it easy enough, mount the grinder, slide the piece over it. Overkill for the little cuts mentioned above, but it occurs to me if I'm going to invest in any glass, I might as well buy tube in bulk and make a column, sight glasses etc. Large diameter tube is surprisingly cheap (cheaper than SS spools) if you pick it up by the case, usually 3 x 5'. If I knew I could easily cut to size that'd be more than I could imagine using for a still and other projects too.

Or I could just find a local glass worker and see what they'd charge for each cut to length. Let the pros handle the part where a $50-75 tube is at stake. Then I can break all the little bits it takes to get a knack for it.

[cranky]

When I got my borosilicate column I had them cut something like 8 inches off the end, I imagine they probably would have been able to cut it lengthwise. I've also seen people cut glass with a hot wire but that is a pretty advanced technique. One thing I thought about was you could cut the ends off of bottles to make a tube to practice on.

[decoy]

Decoy, what about that disc you linked above? How would that work, just in a normal angle grinder? Would it need some kind of water bath / jet thingy? I could build a jig for it easy enough, mount the grinder, slide the piece over it. Overkill for the little cuts mentioned above, but it occurs to me if I'm going to invest in any glass, I might as well buy tube in bulk and make a column, sight glasses etc. Large diameter tube is surprisingly cheap (cheaper than SS spools) if you pick it up by the case, usually 3 x 5'. If I knew I could easily cut to size that'd be more than I could imagine using for a still and other projects too.

Or I could just find a local glass worker and see what they'd charge for each cut to length. Let the pros handle the part where a $50-75 tube is at stake. Then I can break all the little bits it takes to get a knack for it.

That Lenox disc is the new tech for grinders, even if you dont use it on glass, its great for metal cutting.
I tried some standard diamond/tile cutting disks, they where a bit of centre or bouncy causing lots of chiping.
It might have been a fluke the one I used was well balanced and smooth, the lenox blade was very smooth cutting, perhaps cut something hard to wear it down a bit before using it on glass.

No you do not need water.
The cutting particles are silver soldered etc to the disc, so if you can run water over it to cool it, the disc will run longer.
I plan on doing more testing and work with this.
Why?
I can pick up large 10-15mm thick sheets of hardened glass from fencing and shop/office buildings refits and heaps of shower screens for FREE!, do a search on craigs list or what ever your local internet classifieds are.
They give it away as its extremely rare that they can re use it and it costs them $$$ to dispose of it.
If you can cut hardened glass you can reuse excellent building material for your next feature view wall or entertaining area.

This is an example add..
https://www.gumtree.com.au/s-ad/villawo ... 1220182881

[manu de hanoi]

As far as I know hardened glass = tempered glass, except for some speciality "gorilla" glass for mobile phone.

so I'm surprised anyone could cut "hardened" glass without it shattering (I've had my share of explosions).
Btw u can tell tempered glass by putting it in from of LCD sceen (emits polarized light) and looking at it with a polarized filter.

I'm currently looking for borosilicate/pyrex 10 mm thick sheet in order to cut it, is boro cuttable or is it tempered ?

[SaltyStaves]

I'm currently looking for borosilicate/pyrex 10 mm thick sheet in order to cut it, is boro cuttable or is it tempered ?

I've broken old English Pyrex and modern borosilicate glassware and it has never shattered on me.
Most impressive was when I toppled something on the bench and it struck this thermometer like a hammer driving a nail. Punched it right through the pyrex beaker.