Clay additives

[Teddybaebae]

Morning

I have a question about clay additives before I go ahead and start experimenting. Is there a list available of what can be added to clay and what happens when fired. 
 

I've got some st Patrick’s clay and would like to make it more textured and grainy. I was thinking of adding sand but that doesn’t seem to be the way to go. 
 

thanks in advance.

[PeterH]

You might find Kathleen Standen's book Additions to Clay Bodies of interest.

Sampler at:
https://www.yumpu.com/en/document/read/19109768/download-a-free-excerpt-ceramic-arts-daily

UK prices https://tinyurl.com/2p8tsuzf

[Teddybaebae]

Thanks very much certainly worth a look. 
 

So there isn’t a source or directory of add this to clay and this happens

[PeterH]

10 minutes ago, Teddybaebae said:

So there isn’t a source or directory of add this to clay and this happens

I suspect that there is info somewhere about "formulating a clay body", which might include adding grog for texture and iron/manganese for speckles.

Is that your interest, or are you wanting to try more "decorative"  additions?

If it's just texture you want you might start with :
Grog https://digitalfire.com/material/grog

[Callie Beller Diesel]

 

4 hours ago, Teddybaebae said:

So there isn’t a source or directory of add this to clay and this happens

Not for absolutely every material, no. And you can definitely put sand into clay, but the question is what kind of sand? Sand has different compositions based on the parent rock. 

When I was at NCECA in 2019, Rimas Visgirda gave a talk about his work, and a big part of that is different kinds of inclusions. He talks about coarse grades of feldspar and quartz, as well as using things like chicken grit and different kinds of sand. It’s not an exhaustive list, but it does talk about a few things that are used for off label purposes. 

The images don’t start for a few minutes, so don’t be concerned. The discussion of specific inclusions is towards the back half of the video. 

 

[Teddybaebae]

Thanks for the updates. The clay I’m using at the moment is very smooth and I wanted to make it more textured and rough. Almost a bit happy in places. 
 

happy to give grog and iron/manganese a try. 

[PeterH]

22 minutes ago, Teddybaebae said:

Thanks for the updates. The clay I’m using at the moment is very smooth and I wanted to make it more textured and rough. Almost a bit happy in places. 
 

happy to give grog and iron/manganese a try. 

Just to emphasise the iron/manganese oxides are for visual speckles, not texture.

[Teddybaebae]

So what could you add other than grog for texture? 

[Min]

8 hours ago, Teddybaebae said:

So what could you add other than grog for texture? 

There are good suggestions in the link @Callie Beller Diesel posted above.  If you try chicken or chick grit make sure it's the type made from granite and not seashells. I haven't used it but I noticed one of the big box stores on this side of the pond carries a few colours of decomposed granite ground cover, that might be something you could look into in the U.K. that would be worth trying. It would probably need sieving to get the size bits you are looking for. If you want something to burn out of the clay to leave voids there are all sorts of things that will work, just a question of trying various combustibles  and seeing if you like the finished result. Coffee grounds, rice, sawdust etc.

[Hulk]

Sand is mentioned above also (somewhere...) - several of the clays I've tried have some sand in them. Some sands are "sharper" than others (where the edges aren't as worn down/smoothed). Sand doesn't absorb water; however, I believe some grogs do, which can accelerate the clay's absorption of water (and hence, also speed up drying).

Silica Sand (digitalfire.com)

[Teddybaebae]

On 12/12/2021 at 3:22 AM, Min said:

There are good suggestions in the link @Callie Beller Diesel posted above.  If you try chicken or chick grit make sure it's the type made from granite and not seashells. I haven't used it but I noticed one of the big box stores on this side of the pond carries a few colours of decomposed granite ground cover, that might be something you could look into in the U.K. that would be worth trying. It would probably need sieving to get the size bits you are looking for. If you want something to burn out of the clay to leave voids there are all sorts of things that will work, just a question of trying various combustibles  and seeing if you like the finished result. Coffee grounds, rice, sawdust etc.

I also really the like the idea of adding household things to the outside of the clay for effect. This is my first firing so my experience is very very narrow