Ian Currie Test Tiles Forums?

[tb001]

I've been reading through this thread and love some of the results you're getting! I had planned on doing something similar to the mat you've developed, though more for testing colorant blends vs glaze ingredients. 

The idea of having some sort of vertical test in a grid is really intriguing.  If you had the spacing worked out correctly, using something like 12 or 24 well plates to mix glazes and dip the tiles might work. Amazon and eBay sell lots of what's meant to be disposable lab equipment that can end up being pretty cheap if you reuse. It's often used for doing medium thruput work where you're looking at a lot of variables, so perfect for this sort of application.

Also in agreement w glazenerd on some sort of g/in^2 or specific gravity surrogate.

I finally have my studio finished and kiln hooked up and excited to get started glaze testing again, though will likely be a while as we're due with our second child in a few weeks. I find the glaze testing one of the most rewarding aspects of  ceramics--so many variables in terms of clay and firing cycles alone! It definitely appeals to the former scientist in me!

 

 

 

[Joseph Fireborn]

On 11/26/2017 at 1:40 PM, glazenerd said:

Joseph:

if you are going to keep it as accurate as pottery studio standards allow: perhaps  apply. Glaze glaze in grams per square inch. Or some degree of recordable standard of glaze.

I was doing that before. I was putting 2ml in each cube, which I could tell you the dry amount in. I can tell you the amount of glaze per the area of the tile. But I won't continue doing that because in a potters world that really never matters. So it really isn't worth it unless I am writing lab grade scientific documentation, which I am not.

Plus once I start dipping the 2ml thing will be thrown out the window.

[High Bridge Pottery]

That has always been my confusion, how do you work out grams per inch? @glazenerd

[Joseph Fireborn]

On a flat tile you know how many grams will be on the tile based on how many ml you add to it right? So if your adding 2ml of glaze fluid and that contains x amount of glaze per ml then you can work out the rough math. In reality, what is the point of it because application on real pots is never done this way. It is either sprayed, dipped, or poured all of which would be absurd to try to measure. 

Edited November 30, 2017 by Joseph F

[High Bridge Pottery]

That's what I mean, is there a way you can get a figure for a sprayed, dipped or poured glaze.

The more variables you can pin down the better.

[Joseph Fireborn]

For sprayed yes, because you could measure the amount you put into the container to spray, but then you would have to say your getting 100% onto the pot. which is unrealistic unless your holding the gun point blank. of course you could do this or atleast estimate the amount going on a pot say like 75% or something, then add that into your calculations, but its not very scientific. 

I guess you could do it for dipping as well, by weighing the container after the dip to see the amount of liquid weight removed, then see how much 1 ml weighs and do the math.

Edited November 30, 2017 by Joseph F

[glazenerd]

Joel:

someone recently posted a gram per square inch table in one of the threads??????  I know with crystalline, I figure 0.45 per SI on tile and 0.65 grams per SI on vertical. Long while back I dipped a piece twice, two seconds each time. After it dried I did my best to scrap it off: came out to almost 0.30 grams per SI. I keep it simple 1 inch by .1 inch = SI.  Dipping is what throws me off, there is no measurable way to determine thickness, but I am the odd ball in this case.

when I am spraying pieces; I measure the height by width plus 30%. Always has gotten me close enough for crystalline work. Would be way too much for regular glazes. So my info is not going to work for 99% of the potters. For testing however, it should.

tom

[Min]

4 hours ago, High Bridge Pottery said:

That has always been my confusion, how do you work out grams per inch? @glazenerd

Hi Joel,

About 1/2 to 3/4 of the way down in this there are a few charts for determining approximate surface area. Measuring the glaze then applying a set amount to predetermined surface area to get a consistent thickness of glaze layer. When I first started spraying glazes I did this to get the feel for how much to apply. It's not something I would do on a regular basis.

Like Joseph said though, it's just not the way we work and isn't practical for doing much other than tiles.

[Joseph Fireborn]

Has anyone ran any currie grid test on nepheline syenite glazes and I am trying to figure out where to start? I think I am just going to run a grid with neph, ball clay/kaolin and silica as my only additions. I am looking for something very specific to finish up the design I am working on right now. I was just wondering if anyone has done this or something like this in this thread so I can get any tips you found out? I am looking for something very specific. I have an idea in my head of what I am working on and I must complete it, and I know nepheline syenite is going to be the answer based on what I can see from other glazes using it. I want a really stiff glaze that has depth in the networks of crazes inside of it.  Do you all think this is the right place to start? 

Actually, on second thought looking at the melting point for neph I think I will add 10% 3134 to it, because once the clay and silica get in there, I don't think much is going to happen.

I think I will run it this Saturday. 

Edited January 25, 2018 by Joseph F

[High Bridge Pottery]

Closest things I have is this tile with 100% soda feldspar or the one below with 50/50 soda feldspar and whiting. Never bought any neph. Cone10

Edited January 25, 2018 by High Bridge Pottery

[Joseph Fireborn]

Tile 23 and 24 look very nice on that second grid. I am looking for a stiff glaze that crazes basically. I am sure I will figure where to start this weekend after I get the currie tile going. Thanks for your tile pictures.

Edited January 25, 2018 by Joseph F

[High Bridge Pottery]

I think I can picture what you are looking for but it's not something I have come across. Maybe a test will come to mind while I dream at night. 

[Joseph Fireborn]

Aye. Many ideas come to me at 3am. That's why I have like 4 notebooks spread across my house. One in studio, kitchen, bedroom, and office. Lol. Not writing down ideas is a bad!

[Joseph Fireborn]

I did some quick searches on glazy and found this: 

https://glazy.org/recipes/7270

This is sort of what I am after. I need to read tonight in my book about potash vs neph syenite. 

[glazenerd]

Info Joseph:

potash does not melt suddenly or completely (disassociation) at 1150C it forms a high viscosity glass, with slightly lower Coe than soda. The drawback, once you get into the 1200C range, it will eject excess silica which becomes cristabolite. So as you increase potash, lower silica to the lower side of limits. Nep Sy is source dependent, meaning from which mineral it was processed from. Soda melts completely at 1118C, with lower viscosity than potash; but with higher COE. 

So know you have some brain food courtesy of Ougland & Brindley.. British Ceramic Society. I would also recommend you ditch the ball clay and use kaolin only. You will need the extra alumina to for strength. You can increase the viscosity of soda by whiting additions, as Joel points  out.

for more information: visits my website at www.donothaveone.com. Sorry, humor

nerd

Edited January 25, 2018 by glazenerd
I was going to correct my grammar, but this notepad has it's own correcting...sure sure

[Joseph Fireborn]

@glazenerd Im about to read all about potash and neph sy. I don't mind if the surface forms some kind of crystal structure and matte slightly. I am not worried about leaching since there won't be any materials in the glaze to leach out anyways. I actually want a crackle type surface but not as glossy as that one. More of a shino ish look but still have the crazed lines. I can't describe it. I have seen it on work before.

I just realized I linked the wrong image. I like this one much more: https://glazy.org/recipes/7269 but still it isn't what I am after. Unless it can be put on thick and not move or crawl. I don't really use online glazes much anymore as they never travel well. But it looks like a good place to start. I still think Neph Sy forms a better-looking glaze.

[Min]

Looks somewhat like the Snowflake crackle glaze. There is a similar recipe on glazy here, which is close to the one in Britt's ^6 book, the recipe on page 74, the Version 4 not the original. Even if you needed to add some clay to stiffen it up I imagine it would still craze given it has over 80% nepsy in it. Or the Kuan crackles on the same page.

[Joseph Fireborn]

Yea I have tried tinkering with the snowflake crackle. I can't get it to do what I want, plus I want something with a more matte surface where snowflake is super glossy. 

I am not trying to be difficult I appreciate all the help. It is the last part of the puzzle for what I want in my work this year. I am trying to make some work for friends who have asked for some in the past. I also want to sell some work this year again as well.

Edited January 26, 2018 by Joseph F

[glazenerd]

Min:

when I click your link! I only get a blank page. Could you post a full link please? Probably just this stupid I-pad, that I do not know how to use very well.

ty Tom

[Min]

14 minutes ago, glazenerd said:

Min:

when I click your link! I only get a blank page. Could you post a full link please? Probably just this stupid I-pad, that I do not know how to use very well.

ty Tom

No problem, https://glazy.org/recipes/11146 I thought the image of it on the white stoneware tile looked similar to Josephs example and it's using nepsy as Joseph was asking about. (you might like the name of it) 

 

 

[curt]

Some new currie test tiles here.  Testing a slightly modified version of the basic ash glaze in Britt's High Fire glazes book.  I have used this glaze several times in both oxidation and reduction, with some promise, and wanted to run some currie tiles to explore variants.

However, these tiles were all from the same firing in a small LPG kiln which, in the main, did not get to temperature.  Target was cone 10, and some parts of the kiln may have reached cone 8 or 9, though, including one of the tiles below.  However, the two cone packs(8, 9 and 10) did not budge.

This is a non-standard currie tile.  It was a bit tricky to do a currie tile with this recipe because silica is not a specified ingredient in this glaze.  The closet thing to silica was the zircon (the only non-flux beside the kaolin), so that is what I used in place of silica for the currie tile.  I also adjusted the amount of silica (er, zircon) down from 50 to 18, because zircon is so refractory.  So when you look at the tiles, remember that where you are expecting to see silica, it is zircon instead, and much less of it than what the silica normally is. 

In the first three pictures below, I am going from most fired to least fired as we go down.  The original base glaze recipe is very close to what you see in cell 4 in these tiles.  Clearly it needs to get hotter to get properly fired.

Even though this glaze is underfired, I wanted to share it because there is some interesting information here.  

First, and probably most dramatically, there is a sharp break between the left two columns and the right three columns.  This is almost certainly the opacifying effect of the zircon.

Next, I was surprised to see that the meltiest (or maybe just the glossiest?) point of these tiles was consistently around cell 17 or 18.   Usually corner C is the best melter.  Probably an artefact of the non-standard set up for this tile...  

Also, as we go down you can begin to see the striding figure in each cell near the bottom of the tiles.   This surprised me, as it is almost all flux down there (corner C is 50% ash, 50% neph sy).  So why that would be melting later than cells which have much more kaolin and/or zircon in them is something I am still thinking about (thoughts?).

Plenty of surface tension evident in the top two rows, and maybe even down into the third row a bit.  

Many cells were raised and puffy, with apparently still a lot of off-gassing to do.  Also plenty of little off-gassing holes in the glaze surfaces in many cells.

Finally, the last picture are some test tiles with this glaze, mainly in reduction.  These tiles DID get to a full cone 10 or thereabouts.  Interesting yellowish color on right tile, which is on white stoneware in reduction.   The right two tiles both have a slightly even more modified version of the basic ash recipe that has additional neph sy.

Interested in thoughts or reactions.  Also, I have one more tile with this glaze which I hope to fire soon.  Hopefully that one will get to temperature!  Will report back with that later. 

    

[High Bridge Pottery]

Them pesky eutectic.

 

Maybe too much calcium? in corner C. It is reminding me of a tile I did with whiting and soda feldspar. 

[curt]

Note: OK, struggled for quite a while to get this photo to upload, first time doing it with new software update.   Tried to upload to my gallery several times with different file sizes but no joy.  Every time I hit "submit photos" button after uploading, nothing happened (ever).  If anyone can point me to instructions would appreciate it.

As promised from tiles above back in mid-March, this is the same glaze as above, but in oxidation (electric), and probably fired to around cone 9 (cant say for sure because I did not fire it.)

Most distinctive feature is still the stark divide between not so much zircon (2 left columns) and too much zircon (3 right columns).   Other than that, this glaze in oxidation appears to be behaving very similar to reduction, with the obvious difference that the light iron content here is making the glaze brown, rather than green as it did in reduction (see tiles above). 

The bottom 4 cells of the middle column are probably the most interesting to me after looking at this for a while.   I am tempted to do another tile that zooms in on this area to see what is really happening when the zircon/silica is changed in much smaller increments.   At some point between columns 2 and 3, the zircon is going to appear on the scene.

I know zircon is very refractory, but I can't tell (even after looking with 800x zoom microscope) if the zircon is just sitting in this glaze doing nothing but looking white, or if it is getting moved around, dissolved, or otherwise homogenized into the melt.  Obviously small amounts simply vanish, as we can see from the two left-most columns. 

The original glaze is around corner D, basically matt white.

I am waiting on one more refire of the reduction tiles above and then I will post them again, maybe with a bit of compare and contrast if I can manage to organize the photos.

Edited June 10, 2018 by curt

[Joseph Fireborn]

Curt, tile 23 there is remarkable. I would love to see that on a bottle or something. I wonder if the same coloration would happen though. 

Also tile 13 is really nice. 

Edited September 1, 2018 by Joseph Fireborn

[Joseph Fireborn]

Hey, fellow Currie peoples. I have 2 tiles going in tonight! Going to necro this beast of a thread! Probably won't be that much to look at, but it is my standard white glaze that I use on all my work. Adapting it to be slightly more matte and just to see if there is anything interesting with it.

On a side note, this is the first time I am actually using my currie grid tiles from the foam slab roller (which I sold). So it was sort of depressing using these beautiful tiles that I made so easily, that I can't make anymore because I sold the slab roller because I never ended up using it. Hahaha. 

Has anyone been doing any more testing?