Ian Currie Test Tiles Forums?

[curt]

Thanks Pieter. Now that I have realised the photos are actually appearing with the correct orientation (cell 31 is bottom left hand corner) could you identify the cells you are asking about again? (Because cell 25 of the tile is not actually in any of these photos)

[Pieter Mostert]

I'm asking about tiles 11 and 12. In the top photo, these two cells have a lighter, wrinkled strip along the top.

[curt]

Ah, those cells are actually repeats of cells 31 and 32. Since I didn't expect much to happen in that part of the tile I monkeyed around with cells 11 and 12 by adding another glaze to see how it would bleed into the basalt glaze, which is what you can see happening just at that top edge. It didn't bleed at all as it turned out, I think because the other glaze was too stiff.

[Joseph Fireborn]

So I have an interesting question. I was making currie grid test today. After I made the 2nd one I started to realize there was a major problem with wasted opportunity per little cup.

 

I follow the book instructions exactly as he says. However when I am done I have 35 cups with plenty of wet material in the cup for another test. After I pour all this back into a waste bucket to dry it turns out to be a lot of glaze. I am even doing 2 grids per 1 mixing. I am not sure why he says you need a double batch for 2 grids.

 

I make 2 grids each time: one for slow firing and one for fast / or /  one for cone6 and one for cone7. 

 

I noticed I only use about 2ml per grid, mine are about 1x1''.  We are mixing a 48ml cup per glaze tile, then we are only using 2-3ml per tile. This seems to me that there is a lot of room for volumetric additions of colorant if we can withdraw the exact same amount of glaze for each tile carefully.

 

For example. If I withdrew 2ml per tile. Then I would have 46ml remaining in each cup. I would like to say go back and add 1% oxide or colorant to each cup. Then mix each cup again and do another grid. Which would leave me with plenty of glaze to stir the small cups again. 

 

Reading on page 120 he talks about doing volumetric additions.

 

I usually bring my 300g batch up to 470ml equalizing volume. According to his chart this means I have 30.6 dry ingredients per cup before I take out any glaze. This means that 1% addition = 30.6 / 100. Which would be .36 grams of oxide. 

 

To prepare this amount for 35 cups I would need to do this math: 35 x .36 = 12g of oxide. I then weigh this out and mix it with water. 

 

I am stuck at this part. In his example he just says 40 cups to 80ml total volume. Where does he get the 80 from is he just picking that as an arbitrary number? 

 

Then he says to take 1/40th of the total volume(80ml) into each cup. So I would take 1/35th of 80, which is 2.2ml. So I could take 2ml of the oxide mix, and add into each cup. 

 

So my real issue here is I am not really going to have 48ml in each cup. Cause I am going to do 2 grids first, which removes lets say 2ml per each tile. So my cups will now have 44ml in them. I will be adding 2 ml more to it, which is 1% of the original amount of 48. I am assuming this is close enough to 1% not to really worry about the math of trying to scale it down. 

 

I guess I could always just do a line blend between 1 and 5% later on if I do like the addition of an oxide.

 

Does all this sound right to you currie people? Am I just doing something wrong to have so much glaze left over in each cup. I don't understand why he never mentions it in his book. It seems like a huge waste of time to mix all those cups then not utilize them fully. 

[Magnolia Mud Research]

Joseph,
 
I did a full Currie grid test program a few semesters back.  I cut overall volume of glaze to about 1/3 of his recommendations, and only mixed 'batches' for the four corners.  The glaze mixtures for the remaining 31 spots were created using syringes to produce just enough glaze for each spot.  It was easy to figure out how much glaze was needed to cover each spot on the grid tile and to work from that to how much is needed from each corner batch.  The limitation ultimately depended on the smallest amount that can be measured accuratly with the syringes on hand. Everything then scales from that amount.  All the calcs were done in a simple spreadsheet so I only needed to squirt so&so ml of slurry from each corner bucket into a pill bottle, shake(not stirred), pour onto the proper place, rinse the pill bottle, and repeat.  In the end I still had significant leftovers in the four corners, but much less than if I had exactly followed Currie's program.
   
My conclusion for his 'program' for the overall exercise was to make it overly simple to potters that are intimidated by arithmetic.
 
Overall, the approach of using volume blending along with the multi axial line blends is both sound and efficient.  The large batch sizes are to reduce the effect of small random measurement errors.  It can improve precision, not necessarily enhance accuracy.

 

LT

[Joseph Fireborn]

I agree with the larger amounts to reduce error. I don't mind wasting the small amount of materials for like a single grid test or something. However I am at the point where I am filling my 2.7cuFT kiln with slip test, oxide stains and washes, melt test, and a bunch grid tile test. So I want to get the most bang for my buck. Which makes me want to attempt this method of using the cups instead of pouring them out. Your method sounds pretty nice to reduce the waste, however I am thinking about just using the waste for more test. I have like 24 grid tiles drying right now. I plan on using them all in the coming weeks. 

 

I need to figure out the math backwards. So if I have 44 ML in a cup, what is 1% of that amount in say an oxide. That is what I need to figure out. I guess I will sit down and figure the math out. My old brain so rusty.

[Joseph Fireborn]

So I need to figure out how much grams come out of 2 ml of glaze. Here is my math thoughts(please correct if wrong because im just free flowing this here)

 

**Using 300Grams of glaze, and 470 equalizing volume**

 

Dry Weight: 300 x 4 = 1200 grams  

Wet Volume: 470 ml x 4 = 1880 ml of glaze

 

1200  / 1880  = .638 

 

.64g per ml of glaze 

 

So a cup full for the first time will have 48ml, which will be 48 x .64 = 30.72 g of ingredients. so at this point. 1% addition would be .3 grams of oxide.  I did this math earlier. This is correct.

 

So now my cup has 46ml of glaze(took 2 ml out for a grid spot). now I have 46 x .64 = 29.44g of ingredient, so it it would be still around .29 or close enough. if i like the result i would do a line blend anyways.

 

at 44ml of glaze. took out 2 more ml for another grid spot. now i have 44 x .64 = 28.16 of ingredient. So it would be .28 grams of oxide for 1%

 

Then Equalized to 80ml, so it would be 1/35 of 80ml = 2.25 ml added back into the cup to get the new grid test which would contain the perfect amount of oxide that equals the 1% I need for adjustment. So I could potentially get a lot of different test out of this. Doing something like 1% copper, then 5% titanium, then 5% more titanium.

 

I think my math is right. I can just take out as much as I want as long as I keep track of the ml I am removing. Which means I can get many grid test via a single blend of ingredients. 

 

Of course all of this will need to be retested again and line blended to get the exact percents since this is eyeballing a dropper over many times per hour. lol. 

 

Still its a much better way to utilize the grid method. I will report back on this tomorrow. I was about to make a third batch of glaze and I was like, there has to be a better way to do this math wise. The whole double batch thing seems absolutely insane now, unless I am missing a key point in my thinking. I wish Ian was alive today, I would love to thank him for this method. It is beautiful for what it does, which is give you a starting point for a surface and detail of glaze that your looking for.

[Magnolia Mud Research]

It looks ok,

 

The key is keeping track of what is being removed and adjusting for it.

 

I will review your summary tomorrow again.

 

The bookkeeping is tedious!!

 

LT

[Joseph Fireborn]

I think I can make it less tedious. Just use a 2ml syringe. The math can be standardized for the new oxide additions each time with a chart on the 2ml removal and additions.

The most important part is it doesn't have to be exact as we can always line blend 5 tiles real quick based off the grid we wanted to get a better representation of the tile we want. The main point of the new additions is to see a lot more grids with very little work after your initial investment of time.

As long as we decrease the total glaze numbers to base the oxide percent addition we should be pretty darn close.

We can include the oxide additions for numerous addition as well. So if we add 1% iron. We know the total grams per ml of the cup now. Then say we want to add Cobalt. We could know the accurate one % using the math quickly.

This sound correct? I just woke up.

 

I think I will build a chart that shows the quick maths based on 2ml withdrawals and additions with the % additions and the decreasing amount of base. I will post it once I finish it. I have to run some errands this morning. 

 

I really think this addition to the currie method is substantial. Unless I am missing something here, I think it could drastically improve the speed and long term results of testing with this method. You go from 1 grid(the base) to what ever you want. You could add 2% titanium dioxide, 10% iron, etc etc and do this numerous times in what ever order makes the most sense. Quickly creating a glaze that has multiple factors. You could see what cobalt does, then cobalt and copper, then cobalt copper and iron. All while seeing the clay, silica and flux adjustments along the way. 

 

Of course you still have to do the additional leg work of firing vertical tiles, but it is a super fast way to get hundreds of flat results to look at. The best part is it doesn't waste so much ingredients with little results, which the standard test does. The other good part is you don't have to measure out all those cups a second time. You just have to syringe the quick 2ml from a well stirred oxide mix and add it to the 35 cups and mix, which shouldn't take more than 5-10 minutes total once you get the hang of it. Particularly if you have tools, cups setup for perfect mixing and an exact syringe.

[curt]

If you only ever want to do ONE currie tile per glaze once in one firing in one kiln, I agree that Currie's suggested amounts may seem like a lot. However there may be a few reasons that it is not as excessive as it may seem at first glance.

 

First, many of us - including Currie himself - use the same glaze on several different types of tiles in multiple firings in multiple kilns. For example, If you review the rest of this thread you will see people talking about multiple currie tiles made of different clay types (eg, porcelain, light stoneware, irony red body, etc) and oxidation vs reduction firings, first in test kilns and then possibly in larger, production-oriented kilns, etc.. In my own experience, I have fired the same currie glaze on up to four different tile types in both reduction and oxidation for a total of 8 different tiles using the same glaze (or was it 10?

 

Similarly, if one wants to add colorants or other modifiers (eg, titanium) to create a whole additional run of currie tiles from the base mixtures, better to have too much base glaze rather than too little.

 

Also, I believe it is easier to thoroughly mix and homogenise the 35 individual cups when there is more than a few mils of liquid in each. This will give better application and better results, particularly for cells that quickly settle out.

 

Finally, if glaze application into the individual cells on a tile is too skimpy, the fired glaze surface in each cell may be too thin to be representative of actual use on a pot. Also, having insufficient glaze in each cell will prevent the part of currie testing which indicates how glazes melt down, break, settle, craze and/or heal over.

 

Before we get too obsessive over a few mils of glaze "wasted" in tests, probably want to think how many buckets of glaze we have poured over mediocre artworks that should have been melted down and recycled.... perspective...

[Joseph Fireborn]

Curt,

 

I understand and agree that you can use the one test on multiple clay tiles or different firings. I have done that and I was doing that yesterday. I have been firing cone 6 and 7 comparing the results between glazes. So I understand that part.

 

However for those of us who only want to fire in electric and who are narrowing down our work to one clay body and one schedule, it really is a lot of work for a single grid. This is the reason I am searching for another way to improve an already awesome method that provides a lot of results to a more diverse method for time constraints and material waste for only a single grid.

 

I understand that it can better to mix inside the equalized volume ABCD containers. However doing so results in needing those double batches. In his book(pg121) he talks about mixing in individual cups as I am talking about here, so he didn't have a problem with that method. He did it in 48ml of glaze as opposed to 48ml minus say 2 of that volume, which is insignificant 4% removed and 96% of the original contents still there. Comparing that to dipping of a bucket of glaze is like saying you dipping a few mugs is removing to much for the next mug to be accurate. I could see maybe on the 4th addition since you would be around 12% total base missing, but still that isn't much as long as we can accurately mix and syringe from that cup, which we assume we can do from the original curry. Again the total volume in the cup remains the same for each test. 

 

As far as the 2ml being a small amount for the grid. I am just using that as a number for the math example. You could use more if you wanted a thicker application. I don't apply most of my exterior glazes thick. So I have no interest in firing a test with thick flat glazes compared to thin ones as that is how I apply my glazes to my work, which is why I am running the test. However I don't really think 2-4ml of glaze on a 25mm tile is thin. It filled up the tile enough for me to scratch the glaze almost a 1mm deep, that is half of what he considers a thick application being 2mm. I think that is more than sufficient for my work, but again, one could go to 4ml and still it isn't a significant difference in the total volume of glaze for the next application with an addition.

 

I could also just modify my grid to have a pool instead of a ridge on the tile(might do this soon). I made my grid to have the type of changes that I have in my work, which is normally ridges for glaze breaks. I understand a lot of people fire the currie method to see the research and science behind it all, for me that isn't the purpose, I want results that I can test and modify to replicate on my work. It doesn't make any sense for me to fire a tile with 2mm thick of glaze, I will never have a single glaze that thick on the outside of my pot, unless its an oilspot.

 

Going from 48ml to 44ml with an equalizing volume of 470 is only 2.72 total mixed grams of difference between 48ml original. The amount in the cup is insignificant as well as far as the volume removed for mixing as you add back the same amount of total volume that you withdraw. So the cup remains a total of 48ml for continuous easy mixing. Maybe on the 3rd or 4th application I could see maybe you don't have enough base, but I doubt it(mixed sufficiently). As you will be decreasing the % additions based on the removal of glaze and the previous additions each time. So math wise the numbers work, it is just in the testing process one could make mistakes, and that is with any scientific test. The results are in the methods. 

 

If this does succeed, one thing I will be doing is finding a small immersion blender that can fit down inside my little test cups. This way I can just make my own cups that are straight sided and stick the blender down inside of the test cups. 

 

However I will say all this is theory at this point, so it could fail horribly. I plan on trying it today/tomorrow, and firing in a few days so I will see the results first hand. I am going to start with a small change in oxides so that I can more accurately compare the differences and see if the tile grid base matches with the additional oxide closely. 

 

I appreciate the thoughts and concern, definitely makes me critically think out the problems a lot better.

[High Bridge Pottery]

Is he talking about in the book mixing up an 80ml solution that contains 40 1% additions? Then 2ml = 1% oxide with a little to spare. That seems to be the idea you are going for anyway. 
 
It is a tough one as you are taking out 2ml of glaze then adding back in 2ml with less material in so slowly the total dry glaze is going down. I worked it out to about 1gram every 2ml test taken with adding 1% oxide in but then I get really lost in too much maths trying to come up with a simple solution.
 
I remembered an equation that if you know the ml and the weight of glaze you can work out grams dry glaze per ml. Well I had to look back over old threads to find it.
 
It will be (((weight of glaze - ml of glaze)5/3)-g oxide additions) x ml of glaze = g dry glaze
 
So you can take out a known volume, weigh the glaze, minus the change in ml and multiply by 5/3 to get a good estimate of total dry glaze. Still you are adding in oxide so you will need to take that off. Now you have total dry glaze in the cup and can mix the 80ml oxide solution to add to each cup.
 
I am still not sure this is actually right but this is where I am up to. Not able to weigh glazes to test if it works.
 

Because the density of dry matter in most non-lead glazes is about 2500 g/l 
and the density of water is about 1000 g/l, the formula simplifies to: 

g dry matter per liter of slop = (density of slop - 1000) 5/3 


So, for example, suppose that a liter of your glaze slop weighs 1500 g. 
Then the amount of dry material in it is (1500-1000)5/3 = 833.3 g dry matter 
per liter. And since the total slop mass is 1500 g, we also know that the 
glaze slop contains 1500-833.3 = 666.7 g water per liter of slop. 

For most purposes, this formula is accurate enough. For greater accuracy, 
you (or your glaze program) can calculate the actual density of your dry 
glaze and you can determine the actual density of your local water at your 
room temperature.

[Joseph Fireborn]

Joel,

 

In the book he refers to measuring 40 cups worth of 5% addition of titanium dioxide, then using a glaze syringe adding one fortieth of this volume to each of the 35 cups. He uses 40 cups as an example to make the ml math easy. 1/40 of 80 is 2ml. So basically he makes a batch of 5% titanium dioxide with 80ml of equalizing water. Then he syringes 2ml out of that mix and adds it to each cup. Making each cup have a 5% addition. I don't want to type out the entire page. I can scan it and PM it to you if you want. It is really simple.

 

As far as the maths to work out dry ingredients per ml of glaze, it is in the back of the book. Approx Used Wet Total  x (Total Dry Weight / Total Wet Volume). This gives you the total grams used. Then you divide that by 35. Which gives you grams per cup. Then you can do the math for 2ml = how much grams removed. 

[Joseph Fireborn]

I am building a google docs spreadsheet now. Once I finish it you can take a look.

[High Bridge Pottery]

The way my equation should work is:

 

You take out the first 4ml (could be any known amount) out each cup for two tiles and weigh the liquid glaze left in a cup. Put that through the equation and get total dry glaze in the cup. Mix up the 80ml of 40 x 1% oxide and add 2ml to each cup.

 

Run another grid, put the new weight of liquid glaze and ml through and mix up a new solution of 80ml to add into cups. I think you should take off any extra oxide you have already added to give a better estimate of total dry base glaze.

 

This way I think as long as you take out measured amounts each time you can quickly calculate dry weight.

[Joseph Fireborn]

Exactly man. This is what I am building now. I am almost done. I have to run to my supplier to get some cone packs. Want to make sure the schedule I am going to use is firing to exactly where I want.

 

You have what I am saying exactly in your head the way I am thinking. You remove the amount the first time for the base grid. Then you recalculate dry inside of the wet. Add % increase. place all the test again. recalculate new base again. repeat for as long as you think is accurate for the base decreasing each time at a 4% decrease per test if using 2ml as your mark for tile.

[Magnolia Mud Research]

What you have described will work. 

Check that you have a running totals of solids and water, both by weight.  for what is in the 'cup' and for what is on each spot on the tile.

It takes more words to describe what is happening than there are steps to actually do it.   

 

Have fun.

 

LT

[High Bridge Pottery]

The other thing to do is just accept the problem, even if by 10% addition you are out by 10% what's the difference between 10 and 11. Close enough to go I like between 4 and 6% 

[Joseph Fireborn]

Here is my quick and dirty method for getting these dry mix amounts. 

 

Explanation: 

 

I am holding some rules to make my life easier, you can adjust these if you want, but I want even numbers to make it easy to do efficiently. 

 

1. I will always remove and add 2 ml of volume from the cup, then back to it with the addition.

2. I will always get equalizing volume of the additional batch by using 80ml as my point, mixing 40 cups worth.  This is so that there is extra when I am down to the last few cups worth of material. This is the same with the corner mixes. The math on 40 cups mixed with 80ml volume, makes each addition a perfect 2ml for each cup.

3. By doing 1 and 2. I keep the total volume of each cup 48ml.

 

An explanation of the basis of my math. You only need to input the additions you want to include. The rest is done, and the dry batch for the addition that you want to mix up to 80ml equalizing volume is in the light yellow color.

 

I calculated the dry weight at 300g for each corner, then equalized it to 470ml. I have found almost all my test this is the usual place my A corner feels about right to base the rest of my corners off. If your using some wacky glaze, might have to change this. 

 

An example of my process through the sheet:

• We start with an approximated dry weight of 30.64g in each cup of glaze. This is from the math by Currie in his book.
• After we remove 2ml from each cup our new base is 29.36g. Math is in the spreadsheet cell details. It is also from Currie.
• Then I take the addition I want, 2% increase each time(for this example). Say I want 4 grids after the base grid with each increasing titanium 2%.
• To calculate that I take the new base dry which is 29.36g(after I did the base grid tiles) and multiple that by 2% giving .59g. Then I multiple this by 40 cups. This gives us the dry batch size to mix of our first addition of titanium which is 23.49g (rounding stuff in the spreadsheet)
• We mix and equalize this to 80ml. Then distribute 2ml into each cup.
• Now we have our new dry amount in each cup estimated by the previous amount + our new amount from the additional 2ml. Our new total approximate dry per cup is 29.95g. Total Volume per cup is 48ml.
• Now we stir the cups and take out 2ml, and add to grid, this amount will be approximately 1.25g from the dry weight removed from the addition mix to cup. I multiply this number times my total addition percentage to get a number. Then I subtract that number from the amount removed. This is 2% of the 2% we added to the cup. Thus we can calculate how much of the base came out of the glaze. Which leaves us with the amount of base glaze we removed from the cup 1.22g. Now we take our previous base of 29.36g and subtract this amount. Giving us our new base of 28.14g in a cup of 46ml total volume.
• Repeat this process, continuing to subtract the additional % of the % as we continue adding incremental additions while decreasing the base each time.

The math for all this can be rounded, because I don't plan on sitting there weighing out 26.99 instead of 27, or 28.14 instead of 28. I am just trying to get as close to accurate results as possible. This should work pretty well imo, as we are adjusting the amount of base glaze each time for the new additions.

 

Spreadsheet:  https://docs.google.com/spreadsheets/d/1faETrVYo0Lin_2LU7GYK2BgvOuVLf3cCpefjQzRC5ns/edit#gid=0

 

I tried to explain my thoughts the best I can. My son is singing songs and playing games beside me, so no telling if I made a mistake in my typing, however I believe my math is correct. 

 

It appears the removal of the base does make enough of an impact to warrant adjusting for it. * the more you know theme song.*  

 

Anyways. I know this is a lot of hoopla to most everyone. However I am going to give it a shot tomorrow and I will fire probably Sunday night. I am going to do incremental additions of iron oxide. 

 

I am hoping with the addition of this method I can have 5 grid tiles in around 3 hours. I have the other process down to about 2 hours. So I am giving myself 20 each minutes for the other 4 grids. This is a huge boon to the earlier 2 hours spent on this. Also a lot more results to look at for the initial 2 hour investment.

 

All said and done you could just ball park it and just do a line blend later. But if your going to do all the effort might as well get as close as you can. The dry batch mixes make more of a difference in number when you increase the amount added to say like 5% per addition. Then you start going up 2-3 whole grams!! lol.

[Pieter Mostert]

A simpler way to work out how much base remains after removing 2ml from 48ml is to multiply by 46/48 = 0.95833...

 

So if you started with 30.64g per cup, you'd have 30.64g x (46/48) = 29.23g of the base left after removing 2ml.

 

At the next step you'd have 29.23g x (46/48) = 30.64g x (46/48) x (46/48) = 30.64g x (46/48)^2 = 28.14g of the base left.

 

If you continue in this way, you'll find the amounts differ slightly from the ones in the spreadsheet. The difference isn't large enough to make a practical difference, but for anyone worrying about where it comes from, it seems to be due to the fact that when you work out the amount of oxide removed, the spreadsheet takes the proportion of oxide in the mixture to be 0.02, whereas it's actually 0.02/1.02.

[Joseph Fireborn]

The reason it is .02 instead of .0196, is because it is rounding to 2 decimals. But yea. I think it is close enough. I mean we are still stirring and stuff so it never is going to be exact. But I think it is a good enough place to get the incremental decreases in base to add in the additions to keep the base close enough to make a discovery accurately. If we enjoy a cell we can always line blend again with a more accurate amount of say 200g or something. 

 

Pieter, I am rusty at math, been like 9 years since I used any.. I almost got a degree in mathematics. I changed major after Calculus 3. Just wasn't enjoying it anymore. Linear algebra and combinatorial mathmatics was my favorite.

 

Your formula matches the numbers I got so that makes me feel confident. Thanks for that. Now to just attempt the modified method and see how it goes. Which I plan on doing this afternoon. 

[Joseph Fireborn]

So I ran the addition method today. I will say I overestimated my ability to do an additional grid in 20 minutes. It was more like 40 minutes. The actual measuring and inserting into the cups was fast and easy. Mixed up the amount equalized it and then input the additions stirring the addition cup to make sure it was mixed. However when I went back to mix the addition that was squirted into the cup, I ended up spending about 40-50 seconds on each cup mixing it to make sure it was well blended. This was definitely the huge timesink. After the 3rd grid my wrist was hurting. Talking about 26 minutes of stirring per grid.  So after the 4th grid I had stirred over an hour. However I was able to produce 4 grids today which is a lot more than I could usually do in an afternoon. Took about 4-5 hours total(I took several breaks for food and drink). So estimating that is like 75 minutes per grid(w/breaks). Which isn't bad at all. 

 

I was thinking though, surely there is a small immersion blender I can buy, or even better one that is on a stand that I can just put a cup under and press go for 10-15 seconds then stop and suck out 2ml. With a rapid blender I imagine 20 seconds would be plenty of mixing time. Also this would be super helpful for the addition mix, since it is just an oxide or something in water. So it requires a lot of stirring to keep it suspended while sucking out 2ml each time. 

 

I am going to wait and see the results of my firing on Monday and if the actual process worked even remotely good, I will look to order a stand immersion blender or what ever that is called. (wife told me, its a milkshake blender.... perfecto.)

 

Anyways, more updates in a few days.

[oldlady]

look for a tiny one at a bar supply house.

[Joseph Fireborn]

Okay. Here are the results of the incremental test I ran. I ran a base and then 2 additional tiles. I was going to do a third(6th tile total) and I was just to tired of stirring. So these are the three I did on a base glaze I plan to use often. 

 

I am going to attach them so you can see all three side by side hopefully. They will be in the following order:

 

Base, Base with 2% Yellow Ochre, Base with 2% Yellow Ochre and 2% RIO. 

 

As you can see the math works pretty well. The tiles resemble each other almost identical except for the coloring changes. I think you could easily go as far as 5 tiles deep. The biggest issue is as I said above, stirring in the bloody oxide additions and keeping the oxide addition stirred up. I am going to try a milk frother soon.

 

One of the problems I have with my grid is I need more detail. I am not used to putting so much glaze in a tile. 2% is definitely more than I need. I am going to create my 3rd grid blueprint tomorrow. I need something that leaves a pool inside of the grid so that I can put the majority of the glaze there, then a thinner amount on the outside of the pool, and some type of bulge to see a resemblance of the melt quickly... As for the method, it works good enough for me. Obviously I run an aggressive slow cooling schedule. My favorite tiles are 9, 14, 19.  Tile 9 is exceptional in surface and in interest.

 

My next step will be running vertical test on the 9 total tiles that I liked in varying thicknesses.

 

Thoughts?

[High Bridge Pottery]

Can you share the base? Is the green colour from the dark clay body? 

 

Tile 9 across the board looks beautiful, by 2% do you mean 2ml? They do look a little thick, this is a problem with the tile method. The more I look at them the more I want to sell glaze tiles and forget selling pots. I really like tile 31 with no colourant. Thank you for sharing.

 

I think, if you have an extruder/get one you should make L shape tiles. That is the way I am going to try when I can. They would be something like this but with multiple rows making up the grid and a lot smaller. Maybe 1-2" walls. Stack them like a checkerboard in the kiln.