Pestle and mortar for crushing glass - WarmGlass.com

Pestle and mortar for crushing glass

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Elaine Pieters
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Joined: Thu Apr 03, 2003 8:16 am
Location: South Africa

Pestle and mortar for crushing glass

Postby Elaine Pieters » Mon Apr 14, 2003 12:23 pm

I am new to casting glass and am looking into having a pestle and mortar made for crushing glass. This may seem very archaic but would be a vast improvement on what I do now (too embarrased to describe this!). Unfortunately machinary to crush glass would have to be imported and would be too expensive so I am hoping that a heavy steel pestle and mortar with a 40 cm height and 20 cm diameter will do the job (I work on a small scale at the moment). Has anyone used this method successfully? I am told by the metal forge that the glass will slowly break down the surface of the metal (I'd get maybe 200 crushings out of it before a new surface would have to be welded on) and this will contaminate the glass (they suggest using a magnet to remove small bits of metal). I am told that stainless steel would be stronger and would last longer. Any comments?

David Williams

Re: Pestle and mortar for crushing glass

Postby David Williams » Mon Apr 14, 2003 12:34 pm

Steinert makes one

Cynthia

Re: Pestle and mortar for crushing glass

Postby Cynthia » Mon Apr 14, 2003 1:20 pm

Elaine wrote:I am new to casting glass and am looking into having a pestle and mortar made for crushing glass. This may seem very archaic but would be a vast improvement on what I do now (too embarrased to describe this!). Unfortunately machinary to crush glass would have to be imported and would be too expensive so I am hoping that a heavy steel pestle and mortar with a 40 cm height and 20 cm diameter will do the job (I work on a small scale at the moment). Has anyone used this method successfully? I am told by the metal forge that the glass will slowly break down the surface of the metal (I'd get maybe 200 crushings out of it before a new surface would have to be welded on) and this will contaminate the glass (they suggest using a magnet to remove small bits of metal). I am told that stainless steel would be stronger and would last longer. Any comments?


It will work, but I believe there are easier and safer ways to crush glass into frit. Maybe this would yeild a better result for casting...or not... :roll:

What I do to make my own frit is to heat up my glass to around 1000 F in the kiln. You can pile it as deep as will stay put on your shelf, fire up rapidly then quench it in water. I pull the glass out of the kiln with tongs and drop it directly into a pan of cold water. This takes several trips into the kiln because of the heat (I need to keep myself cool so I don't spontaneously combust). Make sure the kiln is turned off. Wear natural fibers, kevlar gloves, protective sleeves and a face shield. The glass thermal shocks in the cool water and all you have to do is use a little bit of force to break it up. Crush it while it's still submerged and you won't have to worry about the hazards of silica dust that crushing creates. Rinse and dry through a cloth (like a sieve) and you have crushed glass.

It's less work than using a crusher (have one...hate it) and you don't have to search for a source for cow magnets either. It's more fun too. It's dynamic...the glass sizzles and the water hisses as you drop the glass in. The way it fractures up is like safety glass too. It's more chuncky and less shardlike when quenched.

Something to consider.

Brian and Jenny Blanthorn
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Re: Pestle and mortar for crushing glass

Postby Brian and Jenny Blanthorn » Mon Apr 14, 2003 4:34 pm

Elaine wrote:I am new to casting glass and am looking into having a pestle and mortar made for crushing glass. This may seem very archaic but would be a vast improvement on what I do now (too embarrased to describe this!). Unfortunately machinary to crush glass would have to be imported and would be too expensive so I am hoping that a heavy steel pestle and mortar with a 40 cm height and 20 cm diameter will do the job (I work on a small scale at the moment). Has anyone used this method successfully? I am told by the metal forge that the glass will slowly break down the surface of the metal (I'd get maybe 200 crushings out of it before a new surface would have to be welded on) and this will contaminate the glass (they suggest using a magnet to remove small bits of metal). I am told that stainless steel would be stronger and would last longer. Any comments?


U could make a very simple tumbler / vibrator things

Have a search look about 1-3 weeks ago
Image

Mike Byers
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Postby Mike Byers » Tue Apr 15, 2003 10:48 am

I've seen a few interesting approaches to crushing/grinding glass. One was a hammermill (it looked to be the same thing we used on the farm to grind corn for the horses) that was used by Bob Wasser. My wife runs recycling in our area, and has a similar (larger) device that sits on a 55-gallon drum and is used to grind glass. Ruth Brockman in Portland used a machine designed for geologists to crush rock samples; as I recall this would allow you to adjust the size of the particles. But on a large scale, Boyce Lundstrom once rented a big tree/brush chipper and directed its output into a large plywood box. The rental people were amazed at how clean the machine was when he returned it. And then there's the garbage disposal-shop vac machine described in one of Boyce's books. All of these devices, except for the geological sample crusher, would seem to have some serious drawbacks when it comes to safety. When my wife took over the recycling business, the people had been running the glass grinder without a water spray, and had not been wearing respirators: not a good situation!

Bert Weiss
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Re: Pestle and mortar for crushing glass

Postby Bert Weiss » Tue Apr 15, 2003 11:10 am

Elaine wrote:I am new to casting glass and am looking into having a pestle and mortar made for crushing glass. This may seem very archaic but would be a vast improvement on what I do now (too embarrased to describe this!). Unfortunately machinary to crush glass would have to be imported and would be too expensive so I am hoping that a heavy steel pestle and mortar with a 40 cm height and 20 cm diameter will do the job (I work on a small scale at the moment). Has anyone used this method successfully? I am told by the metal forge that the glass will slowly break down the surface of the metal (I'd get maybe 200 crushings out of it before a new surface would have to be welded on) and this will contaminate the glass (they suggest using a magnet to remove small bits of metal). I am told that stainless steel would be stronger and would last longer. Any comments?


Elaine

I use The Steinert crusher and Cindy's quench technique, but I heat the glass in a cheap stainless steel bowl and dump it in to a plastic bucket of water. You need 2 kevlar gloves and don't wear polyester. I dump outside or on a cement floor.

Particle size is a critical design factor and crushed powder generally sucks. You might get away with just quenching and finding something heavy to persuade it to fall apart. My favorite tool for that is the cup from the Steinert crusher. I toss it in to the drained quenched glass until it breks up in to small but managable pieces. Only rarely do I get involved in actually using the pestle part and crushing.
Bert

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Delores Taylor
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Re: Pestle and mortar for crushing glass

Postby Delores Taylor » Tue Apr 15, 2003 12:33 pm

Elaine wrote:I am new to casting glass and am looking into having a pestle and mortar made for crushing glass. This may seem very archaic but would be a vast improvement on what I do now (too embarrased to describe this!). Unfortunately machinary to crush glass would have to be imported and would be too expensive so I am hoping that a heavy steel pestle and mortar with a 40 cm height and 20 cm diameter will do the job (I work on a small scale at the moment). Has anyone used this method successfully? I am told by the metal forge that the glass will slowly break down the surface of the metal (I'd get maybe 200 crushings out of it before a new surface would have to be welded on) and this will contaminate the glass (they suggest using a magnet to remove small bits of metal). I am told that stainless steel would be stronger and would last longer. Any comments?


Seattle Pottery in Seattle WA sells a porcelain ball mill grinder for $800 then you have to buy the 5 gallon drums and the porcelain balls to grind and the screens for sorting the particle size.

Look for a thread on ball mill grinders that Steph Mader posted (this is I think what Brian is talking about). Do an internet search for Seattle Pottery and look on line at the ball mill. Maybe you can build your own for cheaper locally. The ball mill is the best way to go if you want both fine to large sized frit. The draw back is it is noisy, tedious and you have to mask up and sift the various sizes.

The plus is you don't get metal contamination in your project. You can get as large or small of frit consistently as you want (this is controlled by your screen sizes)

Good luck,

Delores

Rob Morey
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the pipe method....

Postby Rob Morey » Tue Apr 15, 2003 1:25 pm

I use Cindy's method first. I set the glass aside to dry and then break it into smaller pieces using my hands. I then use some iron pipe that I purchased from the hardware store. One "tube" is larger and shorter than the other and has a cap on the end. The smaller, and longer pipe is weighted down with all kinds of stuff, just to make in heavier and is capped on both ends. I add the glass and place the larger pipe on the floor, between my feet and then pound and twist like crazy with the longer, heavier pipe. Very aerobic. I sort out the various sizes with screens and then run a magnet through the smallest pieces to remove the metal filings. If I want finer stuff, I use an electric coffee grinder. I can go through a coffee grinder in less than a week, so I don't use it that often. Be sure and wear a mask because of the dust, and don't let anyone watch, they'll think you're nuts.

Jane Lindell
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Postby Jane Lindell » Tue Apr 15, 2003 4:54 pm

Elaine:

Try a search in the old archives. Several people have made frit crushers out of old garbage disposal units. Liam has some pictures:

http://www.warmglass.com/cgi-bin/wgarch ... read=77091

Have you seen Brad's how to's?

http://www.warmglass.com/making_your_own.htm#FRIT

Hope this might help in addition to the suggestions above.

Jane

Gale aka artistefem
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Postby Gale aka artistefem » Wed Apr 16, 2003 9:07 am

Low tech/low cost frit crusher:

Stainless steel 4" dia' pipe x 10" high. One end of pipe has stainless steel flat disk welded into the end for the floor of the crusher. Then a heavy 7" dia' x 1 1/2" thick round steel pipe flange is welded to this same pipe end to provide a stable base for the crusher.

A piece of solid round stainless steel metal stock 5" in length with smaller hand grip size pipe welded in a centered upright position onto one end of the solid stock. The solid stainless piece fits perfectly inside the hollow 4" pipe with just enough side clearance to move smoothly for the glass crushing action.

Check out your local metal salvage yards for stainless scrap and find a welder who can weld stainless steel to put it together for you. My scrap metals cost was under $15 and my husband welded it for me. If you job this out to a professional welder - you may have pay in the range of $70-$100 for their services.

In about 15 minutes I can crush (with no heat/water quenching) 1# of frit -same amount as the small size jar from BE. This does not include grading time with screens.

Be sure to thoroughly clean out your crusher after each use so you don't
get cross :evil: color contaminations.

I also pop a crusher handle sized hole in the middle of a garbage bag and slide it down over the entire crusher to minimize the escaping air borne glass powder particles produced by the crusher.

WEAR A MASK when you crush and do a thorough area clean-up when done.

Karen Smith
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Postby Karen Smith » Wed Apr 16, 2003 6:06 pm

I also use a steel homemade crusher very similar to the one that Gale described that was made for me. Works great for my needs and I've been using it for almost 2 years without any metal breakdown or other problems. GOOD ADVICE WEAR A MASK!
Karen
Garden Glass Studio
Chelsea, MI

Gale aka artistefem
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Postby Gale aka artistefem » Thu Apr 17, 2003 9:56 am

Elaine..check the photo page. I posted an image of my frit maker.

Joanne Owsley
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Postby Joanne Owsley » Thu Apr 17, 2003 3:56 pm

I've never tried this , however, I have READ that you could use an inexpensive coffee grinder for small scale frit making.
Anyone else ever heard of that? :?:

charlie
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Joined: Mon Mar 10, 2003 3:08 pm

Postby charlie » Thu Apr 17, 2003 4:07 pm

Glassyeyed wrote:I've never tried this , however, I have READ that you could use an inexpensive coffee grinder for small scale frit making.
Anyone else ever heard of that? :?:


yes, for a few times. it wears out really quickly. you then have to clean it well and put it back in the kitchen for your spouse to find, and then blame them when it doesn't work.

Greg Rawls
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Postby Greg Rawls » Thu Apr 17, 2003 6:49 pm

Here's what I did:

I went to Walmart and bought two stainless steel canisters (one just a little smaller than the other). Filled the smaller with cement and stuck a pole into it (think churning butter). I put glass in the larger and use the smaller as a crusher. Works pretty good, but no real control over size of frit. Make sure you wear safety glasses and cover the crusher with a piece of canvas to contain flying glass!
Greg

Lauri Levanto
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Joined: Tue Mar 11, 2003 7:33 am
Location: Halikko, Finland

Stainless inpurity.

Postby Lauri Levanto » Fri Apr 18, 2003 6:16 am

I used to by my frit. Now I found a glass factory
that produces crucible melt casts. I get their
pilt (scrap class) very cheap.

The pieces are 1-2 cm thick. Heating and throwing
to water gives me pieces with small internal cracks.
These are visible in a frit cast piece as spiderweb
like structure of microbubbles.

If I crush the glass, how to remove the stainless
steel particles? They are not magnetic.

In addition to coffee grinder I have seen
meat mincer used to make fine frit.

-lauri


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