Jump to content

sparkle/glitter clay for marbling


rawtoast
 Share

Recommended Posts

If you’re talking about the yellowish buff clay that’s in the centre pot on the bottom row of this image, I’d venture it’s some variety of buff/off-white clay. 

If you can backtrack the image to the original source, and see if the potter describes their process, that would be the most accurate way of figuring out what’s going on here. I count 3 shades of what I assume are coloured porcelain, and the yellow could possibly be another version of that, perhaps using titanium? (That last is a total guess.) That would limit the number of clay bodies that they’re trying to work with and keep from cracking apart.

It seems like the artist has incorporated some kind of coarse grog or feldspar chips, possibly 2 kinds to account for the black and white speckling.  This would have taken a fair bit experimentation to get this number of different coloured clays to not crack apart.

Link to comment
Share on other sites

Perhaps Raw is curious about the brown stuff with sparkly golden bits in it? ...on the rim of lowest right piece, and following the clay contours of several others; looks to be brushed on, to my eye.

Ah! In the higher res images, looks like the brown streaks with the sparkly golden bits is indeed a streak of marbled clay.

Edited by Hulk
nice work PeterH
Link to comment
Share on other sites

11 hours ago, Callie Beller Diesel said:

If you can backtrack the image to the original source, and see if the potter describes their process, that would be the most accurate way of figuring out what’s going on here.

Google image backtracks to https://sarahschembri.com/workshops/marbling-on-the-wheel/ and https://weteachme.com/sarahschembriceramics/1022707-marbling-on-the-wheel

Both relate to a course offered by a Sarah Schembri.

Link to comment
Share on other sites

If it's mica, are we assuming that it's added to the body? Certainly sounds easier to get a compatible collections of bodies that way. 

For cone6 it's probably worth reading Digitalfire on Mica  https://digitalfire.com/material/mica

Data sheets for various mica products quote a wide range of decomposition and melting temperatures (as high as 1800C for melting and 1500C for decomposition). A typical melting point of muscovite is around 1250-1300C. However there are many different kinds of mica. Thus it is impossible to give a formula and difficult to give a general chemistry (micas are never employed in ceramics for their chemistry anyway, the mineralogy of the material is what is important).

Doesn't look too promising for cone6 but there are interesting comments on grain/platelet size so I'll continue.

An example of how a small addition of mica affects the fired appearance of a terra cotta clay. The effect is still working at cone 03 (left) but is more commonly employed at cone 06 (right). Notice that it is still visible even under the glaze. This body is popular on the west coast, it was designed by D'Arcy Margesson. Standard grades of mica are too fine for the effect, this is likely Custer LCM Drilling Mud Mica.

jepjylyrag.jpg

No idea how that

Sourcing might be an issue, are there retail outlets for these products?  A Following links from the Digital page give a little more information, and even a a page to request a small (1lb) sample -- presumably aimed at companies intending to order large quantities.

For CusterMica :
Analysis
https://digitalfire.com/material/custermica
Custer Drilling Mud Mica - gets to an error page not found on Pacer site
Products->MuscoviteMica->LCMMica give overview and sample request option

Edited by PeterH
oops misread cone 06 for 6!!!
Link to comment
Share on other sites

2 hours ago, PeterH said:

Sourcing might be an issue, are there retail outlets for these products?  A Following links from the Digital page give a little more information, and even a a page to request a small (1lb) sample -- presumably aimed at companies intending to order large quantities.

See link in the post above. There are  sources in pottery, took a course from Felipe Ortega, coil and scrape cone 04 and lower heat.

New Mexico clay  https://nmclay.com/micar-mica-red-clay

Edited by Bill Kielb
Link to comment
Share on other sites

mica is possible, but so is a white grog made from high fire kiln wash (alumina+kaolin) added to a red or dark clay body, or grog made from bisqued high fire porcelain.  I have used crushed fired dry kiln wash mixed with red clay in a surface slip and get similar contrasting effects for coatings. 

LT
 

Link to comment
Share on other sites

I want to point out quick to @PeterHand @Bill Kielb that the OP is in Australia. I don’t know that they’re going to get a lot of love from North American suppliers, so it might be more helpful to make suggestions of what to look for closer to home.

When I was at NCECA in 2018, there was one presentation on inclusions in clay bodies that would give assorted effects. It’s mostly applied to atmospheric firings, but there were some interesting mid and low fire uses of chicken grit, decomposed granite and assorted mesh sizes of decomposed granite, and forays into making your own grog out of either leftover clay of a different colour, or coloured clay. Rimas VisGarda was pretty focused on more pronounced texture effects, but there are principles here that I think would apply to the finer texture inclusions that appear to be in the OP’s image. Here’s the lecture on YouTube. It does start off dark, but the slides do kick in.

 

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

×
×
  • Create New...

Important Information

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