Jump to content
curt

Ian Currie Test Tiles Forums?

Recommended Posts

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!

 

 

 

Share this post


Link to post
Share on other sites
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.

Share this post


Link to post
Share on other sites

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 by Joseph F

Share this post


Link to post
Share on other sites

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 by Joseph F

Share this post


Link to post
Share on other sites

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

Share this post


Link to post
Share on other sites
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.

Share this post


Link to post
Share on other sites

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 by Joseph F

Share this post


Link to post
Share on other sites

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

Share this post


Link to post
Share on other sites

@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.

Share this post


Link to post
Share on other sites

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.

Share this post


Link to post
Share on other sites

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 by Joseph F

Share this post


Link to post
Share on other sites
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) 

 

 

Share this post


Link to post
Share on other sites

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. 

    large.IMG_1323.JPG.a4dd3ed058d390eaa8d7a0d885c41f02.JPGlarge.IMG_1324.JPG.9372a3d96be6f2d17871fee3b03ddb45.JPGlarge.IMG_1325.JPG.45dff909d3ff91a3ba56858c031f08a0.JPGlarge.IMG_1326.JPG.67b1463c60765db097d66f72a8ea0e6a.JPG

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

×

Important Information

By using this site, you agree to our Terms of Use.