Cone 6 Body W/ Low Warping & Water Absorption

[mrcasey]

I've been making slab built bonsai pots for a while. One of my biggest issues is dealing
with warping. I now use Laguna #75. I chose it because of its low water absorption and color.

1. Can anyone suggest a cone 6 clay body with very low warping and less than 2% water absorption?

2. Are there any online articles that explain how to formulate clay bodies to get the properties that I want? I'm happy to buy the raw materials and mix them myself.

3. Could I just add some grog? I've heard that Ron Lang started with 25% grog in his bodies. Will that up water absorption?

 

[JeffS73]

My experience is limited, but my thoughts from my own tests are:

Yes you can add grog, it will add strength and stability, but it can affect absorption. I don't know if all grog is equal, I.e. if the grog is molochite it probably has absorption of 0% in itself, crushed firebrick would be something else. If you add 25%, it will move your absorption numbers. You'll only know by testing. Use the test regime on digitalfire (SHAB test).

Nao recently recommended "clay and glazes" by Rhodes which describes methods for making your own clay. At the other extreme you could take the "clay bodies" course by Matt Katz at CMW.

Working with what you've got, increasing thickness or increasing internal or external rims will help to an extent.

 

[woodkraftbonsai]

I just transitioned to using CKK6 with Grog from Seattle Pottery Supply - 2% absorption with a 10% shrinkage(the website says 11.5, but that's without grog - they had a worksheet that listed it at 10% somewhere), less than the 12% of most clay bodies that I've tried. Been having much better results, especially as my pots have gotten larger and larger.

I think the best is probably to eventually make your own clay body - I probably will at some point, but this is working for now.

 

[Wood]

I've only just started using Highwater Clay's Red Rock so I can't speak to warping of slabs, but their website claims < 1% absorption at ^6

Red Rock Cone 3-6 | Highwater Clays

Red Rock is one of our proprietary clay bodies which fires reddish with dark specks. Discounts begin when you buy 50 pounds or more. Clays can be combined for quantity discounts.

highwaterclays.com

Red Stone is a version without the manganese sand: https://highwaterclays.com/products/red-stone-cone-3-6

Their Little Loafer's and Speckled Brownstone claim <2% absorption too:

Little Loafer's Cone 5-6 | Highwater Clays

Little Loafers is one of Highwater Clays' proprietary blended wet clays specifically designed for cone 5-6 firing. It is simply fabulous. Save big when you buy 50 pounds or more! Clays can be combined for quantity discounts.

highwaterclays.com

Brownstone Cone 4-6 | Highwater Clays

Brownstone is one of Highwater Clay's proprietary, blended wet clays. Quantity discounts begin at 50 pounds. Fires to light to medium brown oxidation body, it is a good choice for mid-range work of all types.

highwaterclays.com

 

[sorce]

Try Standard 547.
They made a new black sculpture clay too, but it's Manganese so I'm out!

https://www.google.com/url?sa=t&source=web&rct=j&url=https://standardceramic.com/products/798-black-sculpture-clay&ved=2ahUKEwjp7cOHgN_9AhV0PH0KHXViAjwQFnoECBoQAQ&usg=AOvVaw0_Bqo1DKS6npD2hD_AkcWF

The clay body itself won't be more or less warping, the processes will make the determination, making, drying, firing.

I believe grog can cause warping as much as it may be believed to hinder it.
Technically, there is nothing ever saying grog limits warping, only that larger forms are possible with grog, and they never ever ever talk about bonsai pots. Specifically rectangles.

Imagine, grog doesn't shrink, so any higher concentrations of it in a body will shrink less than other places. That will cause warping.

Stick with the east coast!
Fools ship clay!

It's all the same!

Sorce

 

[HorseloverFat]

Try Standard 547.
They made a new black sculpture clay too, but it's Manganese so I'm out!

https://www.google.com/url?sa=t&source=web&rct=j&url=https://standardceramic.com/products/798-black-sculpture-clay&ved=2ahUKEwjp7cOHgN_9AhV0PH0KHXViAjwQFnoECBoQAQ&usg=AOvVaw0_Bqo1DKS6npD2hD_AkcWF

The clay body itself won't be more or less warping, the processes will make the determination, making, drying, firing.

I believe grog can cause warping as much as it may be believed to hinder it.
Technically, there is nothing ever saying grog limits warping, only that larger forms are possible with grog, and they never ever ever talk about bonsai pots. Specifically rectangles.

Imagine, grog doesn't shrink, so any higher concentrations of it in a body will shrink less than other places. That will cause warping.

Stick with the east coast!
Fools ship clay!

It's all the same!

Sorce

This!

I've found my previous warping issues all stemmed from my slab handling, drying technique or uneven wall thickness...

I ran an "dog chasing tail" grift on myself for a year, trying to blame the clay.

 

[penumbra]

Standard 547 is my standard go to clay. I* have used no fewer than a dozen different clays from 6 different manufactures. 547 is an oxide reddish clay that is very heavily groged and has an absorption rate of 0.25%. It happens to work well for my style of pot, which is not to say it is my favorite pick for all my clay uses.

 

[sorce]

We call out Birthday o'clocks.

When it is 5:47, I be like, that's "my clay" o'clock.

Sorce