Cutting platen glass

JTknives

JTknives

Blade Heat Treating www.jarodtodd.com
Knifemaker / Craftsman / Service Provider
Joined
Jun 11, 2006
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I am trying to cut a strip of glass for my platen and having one heck of a time. I'm lucky I found s place that gives me free pyroceram glass. It's a wood stove repair and service place here local and thy said I can have the windows out of the stoves in the bone yard. Lots and lots of glass there and I picked out a nice window yesterday that was 8"x10. Perfect I thought I can get 5 2"x8" strips. Well this stuff does not cut like normal glass. I scored it and tried tapping it and nothing. Tried a rubber mallet on the score line and it starts at the score and goes off where ever it wants. I tried scoring with a thin abrasive wheel and still goes where it wants. So after all that I had nothing left that was usable except a 2"x4" chunk that is glued on to my platten right now.

I'm going back to get more glass today and I think I might have found a way to cut this but I'm hoping you guys have another idea. The local glass place has pyroceram in stock and will cut it for me but thy want $40 for one 2"x8" chunk. Yeah no thanks I will use the free stuff. So any way this morning I get up and instantly wonder if the plasma cutter will cut it. I rush out to the shop and put a chunk on a strip of 15n20 and fire up the plasma. And what do you know, cuts like butter. As the glass cools the cut edge flakes and pops off a very thin layer but leaves an OK finish that I can grind on the disk grinder. But how is this going to hold up, have I stressed it so much that it's going to explode on me?

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I used to cut glass bottle with line-heat and water dunk, so it might works for cutting pyroceram as well. Shallow score one side, then put a red-hot edge (maybe 1mm wide) on opposite side for a few seconds. Dunk glass in water.
 
Pyroceramic glass from a wood stove store is very likely a tempered glass. It won't cut like normal glass. A wet tile saw with a smooth diamond blade might work ... or not. A waterjet would likely work.
 
I thought tempered glass shatters into little cubes, this fractures like normal glass and makes sharp edges. Hen you look at the glass edge on it has a sorta brow/ goldish tint. The store said that the glass in old stoves was tempered but has been replaced with a transparent ceramic.

Here is the window I used. There are lots more there just like this one so I'm going back for more today. I asked him how I cut it and he did not know. But he said hey if you mess it up there are lots more here so come back.
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bluntcut said:
I used to cut glass bottle with line-heat and water dunk, so it might works for cutting pyroceram as well. Shallow score one side, then put a red-hot edge (maybe 1mm wide) on opposite side for a few seconds. Dunk glass in water.
Click to expand...

Since the whole point of this type of glass is it's heat resistance, I doubt that would work.
 
JTknives said:
I thought tempered glass shatters into little cubes, this fractures like normal glass and makes sharp edges. Hen you look at the glass edge on it has a sorta brow/ goldish tint. The store said that the glass in old stoves was tempered but has been replaced with a transparent ceramic.

Here is the window I used. There are lots more there just like this one so I'm going back for more today. I asked him how I cut it and he did not know. But he said hey if you mess it up there are lots more here so come back.
Photo%20Sep%2014%2C%2017%2007%2013.jpg
Click to expand...

That is one type of tempering, but IIRC, there are others. One type of tempering used for heat resistant glass will make it break in wavy and curved lines.
 
Plasma cut, what a great discovery !

I had a Glazier buddy, said they use a wetsaw with a motordrive carriage for precise blade control.

Edit,
Thats cutting laminate glass & I think chemicaly tempered glass. (What I think your fireplace glass is)

Thermal tempered glass cant be cut or otherwise disturbed & maintain its strength.
For example, it can be cut via gentle abrasive, sandblast for example. But the resulting pieces are extremely fragile & probably shatter later on just from temperature fluxuation.
 
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A cork belt in 150 or 220 will do a great job of cleaning up the edges. Use some polishing compound on the moving belt to help.
Frank
 
I'm wondering if I could use some spray adhesive and just stick some stainless heat treat foil to the glass and cut it that way with the plasma.
 
If you want a clean cut, the only way to do it is with a wet tile saw, if it truly is ceramic glass. A waterjet will certainly work as well, but for what you're likely to pay for a few pieces cut, you could probably buy a wet tile saw and do just as well.

Personally, I just buy my platen glass from an ebay seller. They cut it to the exact dimensions I need, and it only cost about $0.55 per square inch shipped, which I'd be hard pressed to beat. I priced out doing it myself once, and even it I already had a tile saw, the ceramic glass would cost me significantly more, just by itself. A local shop would likely be 5 or 10x the cost.

Heck, even if I had a free source for glass, it'd be a while before I made my mony back once I bought a wet saw.

I know eBay links are frowned upon, but if you search "Wood Burning Stove High Temperature Glass Pyroceram aka Robax for Fireplace" on ebay, or simply sort "pyroceram" for the lowest price, you should find the seller.
 
That looks like a good source - I think I'll place an order with him.

I don't think ebay links are frowned on for items of interest to the group. I've posted them before and never had my hands slapped. Perhaps it just needs the linked shortened like this? http://www.ebay.com/itm/371485320145

If this is frowned on, please let me know and I'll be sure not to do it again. Of course, ebay links to an item you are selling would be frowned on big time.

Ken H>
 
I've always bought oversized pieces and cut em down so that I'd have an extra on hand. Wet tile saw and diamond blade.
 
I'm a Glazier and you can't cut tempered (in my experience ) But I have never heard of any tempered Glass being cut . (In most cases it's a nice joke to play with apprentices, to have them go practice Glass cutting when throwing old peices of glass away with a peice of tempered ,cause it's basically blows up ! Wear your safety glasses!)

Google water jet tempered Glass it doesn't seem to work. ;)

Laminated is just what it sounds like 2 peices of glass laminated with a pvb or other type layer.

I haven't tried to cut pyro or heat resistant glass. But since it's free .
score it and give it a snap :) if it does break in big pieces there's a chance. It will cut

Before you cut it (or try to) examine it to see if there are any films on it (I doubt it since it's fireplace Glass )

Wipeout away all dust and grit dip your glass cutter in lite oil , use a straight edge (metal will scratch Glass we use composite straight edges ).
Dip your finger in the oil and run it along the area to be cut .

Then score it with deliberate but not hard pressure in one fluid motion (very hard to describe you have to feel it to get good )

If you can't cut it it will blow up at this point :) keep your glasses on.

After you cut enough Glass you can hear if you made a bad cut (it will flare out or be chippy)

Hope this was helpful
 
Edit this is for glass that can be scored not sure what the rules are with "ceramic glass"

if you need precise peices (with square edges , because you can score Glass very accurately )

You can just over size it a 32 to a 16th of an inch , score it, then wet sand it square. That's what most shops do .

Although we have never used a wet saw because they are too slow and messy .
I'm sure it works fine for small sizes like platens
 
We cut it often using a wet tile saw with diamond abrasive blade.
You will see some small edge chipping along the cut. This can be sanded off fairly easy. The edge will still be razor sharp and will needed to be "killed" (sanded slightly just like a piece of metal) or it will cut up your belts.
You need to feed it slowly or a big diamond chunk will chip it out more than you want along the cut line.
 
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