Glaze Crystals

[Wind n Wing]

I have been perusing the subjects on this forum and havent found this topic or perhaps I just breezed by it.

 

Mayco puts out a series of glazes called Jungle Gems that have bits of colered clay or flake/crystals mixed in with the glaze. Most of the other glaze companies have similar type glazes. The question is, what exactly are the crystals/flakes of color, can you make them yourself or perhaps just buy the crystals/flakes without the glaze.

I haven't found them offered anywhere yet. Of course I don't know exactly what they would be called.

 

At the moment I am trying edge glazing and would like more flake/crystals than the jar contains. Would also like to make combinations to my taste.

 

Any input would be helpful.

 

Thanks,

RJ

[bciskepottery]

You can buy "crystals" separately and add them to your own glaze. Here is one of several offers on the web: http://www.bigceramicstore.com/Supplies/Glaze/glazecrystals.htm Have never used them, so I can't vouch for how well they work. Don't know how they would work with a glaze that already has crystals in it. As John B. would exhort . . . test, test, test.

[Wind n Wing]

You can buy "crystals" separately and add them to your own glaze. Here is one of several offers on the web: http://www.bigcerami...azecrystals.htm Have never used them, so I can't vouch for how well they work. Don't know how they would work with a glaze that already has crystals in it. As John B. would exhort . . . test, test, test.

 

 

Thanks a bunch!!!! RJ

[Guest JBaymore]

One trick that you can do is to mix up a batch of a glaze that you aleready know has some sort of interesting effect when crossed with another glaze. As in when you put one over the other, you get some good effects.

 

Take that dry glaze batch and THOROUGHLY dry mix it. Add a SMALL amount of water to it so that it starts to act more like a piece of clay than a liquid glaze suspension. Form the "damp" glaze material into a slab (won't be easy...its non-plastic) maybe about 1/4 " thick by whatever size works for you for the NEXT step in the process.

 

Find or make a "basin" which will act as a saggar for the slabs of glaze you just made up. This should be out of some form of high fire clay no matter what firing range you are working at. Bisque fire these saggars.

 

Then place the slab of (now) dry glaze into the saggar and fire it up to WELL below the maturing point of that glaze. So for a cone 9-ish glaze you'll likely not be going higher than about cone 2 to 3 for this firing. You will have to expeiment with the firing cone for this, since no two glazes will start their melting process at the same time no matter what the final maturity cone.

 

The goal is to have the glaze slab start to melt enough that it is really forming a hard cold taffy-like slab. But not melt so much that it sticks to the undelying saggar much, if at all.

 

Then take the partially fired layer of glaze slab out of the saggar once the kiln has cooled. Wrap it in a large piece of heavy cloth, get some eye protection on, and beat on it with a hammer. Occasionally check the size of the pieces your are crushing and remove those periodically that are the "right size". Only you can decide through testing what the "right size" actually is.

 

Then mix these pieces into your liquid glaze suspension the way you use the commercial "crystals".

 

 

 

With some understanding of ceremic chemistry, you can start to move the forumlation of the "pre-fired glaze slab" off of an actual "glaze formula" and into something that is a bit more specialized.

 

best,

 

...............john

 

 

 

Oh yeah......... TEST, TEST, TEST.

[BeckyH]

Those crystals are also called frit, and you can buy them separately, in varying sizes. The instructions above are to make your own frit. You can also just filter the glaze and rinse and reuse the crystals from the glaze. You get more control of the effects if you use two plain coats of glaze and place the crystals just where you want them on your third coat.

[Guest JBaymore]

Actually that is not really a frit. A frit would be a melt taken fully to completion through full fineing out so that all the chemical reactions came to completion. This is more a situation of something between "sintering" and a melt. Just enough heat work to stick it all together into a solid mass. You don't want it to fully melt into a glass.

 

If you were making an actual frit, you'd have a fully molten blob of glass fused into the bottom of the saggar when you opened the kiln. The usual frit making process is to pour the molten frit from the saggar / crucible into a water bath at the peak of the melting process. This removes the issue of getting the fully fused but now cold frit out of the crucible. It also begins the process of breaking up the frit into smaller material that can then be ground to whatever final mesh is desired.

 

best,

 

...........john

[Wind n Wing]

One trick that you can do is to mix up a batch of a glaze that you aleready know has some sort of interesting effect when crossed with another glaze. As in when you put one over the other, you get some good effects.

 

Take that dry glaze batch and THOROUGHLY dry mix it. Add a SMALL amount of water to it so that it starts to act more like a piece of clay than a liquid glaze suspension. Form the "damp" glaze material into a slab (won't be easy...its non-plastic) maybe about 1/4 " thick by whatever size works for you for the NEXT step in the process.

 

Find or make a "basin" which will act as a saggar for the slabs of glaze you just made up. This should be out of some form of high fire clay no matter what firing range you are working at. Bisque fire these saggars.

 

Then place the slab of (now) dry glaze into the saggar and fire it up to WELL below the maturing point of that glaze. So for a cone 9-ish glaze you'll likely not be going higher than about cone 2 to 3 for this firing. You will have to expeiment with the firing cone for this, since no two glazes will start their melting process at the same time no matter what the final maturity cone.

 

The goal is to have the glaze slab start to melt enough that it is really forming a hard cold taffy-like slab. But not melt so much that it sticks to the undelying saggar much, if at all.

 

Then take the partially fired layer of glaze slab out of the saggar once the kiln has cooled. Wrap it in a large piece of heavy cloth, get some eye protection on, and beat on it with a hammer. Occasionally check the size of the pieces your are crushing and remove those periodically that are the "right size". Only you can decide through testing what the "right size" actually is.

 

Then mix these pieces into your liquid glaze suspension the way you use the commercial "crystals".

 

 

 

With some understanding of ceremic chemistry, you can start to move the forumlation of the "pre-fired glaze slab" off of an actual "glaze formula" and into something that is a bit more specialized.

 

best,

 

...............john

 

 

 

Oh yeah......... TEST, TEST, TEST.

 

 

John,

Thank you. I have very limited experience with glazes as most of my work is fired but unglazed. But will give it a shot. Could be very educational for me. I have been in my comfort zone for many years time to stretch. And I will of course Test, Test, Test.

RJ

[Wind n Wing]

Actually that is not really a frit. A frit would be a melt taken fully to completion through full fineing out so that all the chemical reactions came to completion. This is more a situation of something between "sintering" and a melt. Just enough heat work to stick it all together into a solid mass. You don't want it to fully melt into a glass.

 

If you were making an actual frit, you'd have a fully molten blob of glass fused into the bottom of the saggar when you opened the kiln. The usual frit making process is to pour the molten frit from the saggar / crucible into a water bath at the peak of the melting process. This removes the issue of getting the fully fused but now cold frit out of the crucible. It also begins the process of breaking up the frit into smaller material that can then be ground to whatever final mesh is desired.

 

best,

 

...........john

 

 

John,

 

A quick clairification of difference between Frit and Flakes. I am understanding your explanation as frit is glass and the flakes you described are glaze that isnt fired to maturity until they are fired to the actual cone I would be working with for the final result. Have I got the jist of it?

RJ

[Guest JBaymore]

Windnwing,

 

The PARTICULAR procedure that I listed above there is not that for making a real frit. What it is is making "something else". Partially fluxed ceramic materials that if allowed to go to completion would eventually be a glaze. You can call them "flakes" or whatever you want.

 

You could do the same kind of thing with an actual frit, if you wanted to go to the extra trouble. Yopu'd have to fuilly melt the original forumlation, then take the crucible (saggar) of molten glass out of the kiln at temperature with tongs, and then maybe pour it onto a flat surface to let it freeze into a "super cooled liquid" state (glass is actually not a solid,.... it is a liquid) and then break it up. Lots of safety issues in doing that; if the place you pour it is damp at all... you can expect flying hot glass, and so on.

 

Commercially available frits are usually ground too fine to to the "crystals of alternate glaze" thing.

 

Technically if you cvan find bottle glass that melts at the required point, you could put little bits of broken glass onto / into the glaze. But watch out for the chemical composition of the bottles. You want silica lime based glass.... not led fluxed glass.

 

best,

 

..............john

[Wind n Wing]

Windnwing,

 

The PARTICULAR procedure that I listed above there is not that for making a real frit. What it is is making "something else". Partially fluxed ceramic materials that if allowed to go to completion would eventually be a glaze. You can call them "flakes" or whatever you want.

 

You could do the same kind of thing with an actual frit, if you wanted to go to the extra trouble. Yopu'd have to fuilly melt the original forumlation, then take the crucible (saggar) of molten glass out of the kiln at temperature with tongs, and then maybe pour it onto a flat surface to let it freeze into a "super cooled liquid" state (glass is actually not a solid,.... it is a liquid) and then break it up. Lots of safety issues in doing that; if the place you pour it is damp at all... you can expect flying hot glass, and so on.

 

Commercially available frits are usually ground too fine to to the "crystals of alternate glaze" thing.

 

Technically if you cvan find bottle glass that melts at the required point, you could put little bits of broken glass onto / into the glaze. But watch out for the chemical composition of the bottles. You want silica lime based glass.... not led fluxed glass.

 

best,

 

..............john

 

 

John,

Sounds like Frit is a ways off in my future. Think I will try your method of underfired glaze chips,flakes,crystals. Seems safer and more to what I had in mind. Thank you very much for your input and direction. No hot flying glass for me.

 

RJ