Jump to content
Sign in to follow this  
Figtreeceramics

Black Clay Advice

Recommended Posts

I suggest since you are new to ceramics working with black clay is like starting a hike with a monkey on your back . No need to do it really-just get another bag of easier to work with clay and save the black clay until you have some experience under your belt.

My 2 cents as ceramics is a challenge enough with the easier materials.

Share this post


Link to post
Share on other sites

Got piles of ugly failed Cassius test tiles but each one is a successful learning experience.

Also testing a clay called Oregon Brown. It takes two firings to achieve the darkest color: near-black. Easier to work with than Cassius but just as fussy to glaze.

Why I'm still at it:

The same pieces in off-white, buff, -dependable, etc; clays, just don't have the drama of the dark pieces. Yes bloating, occasional cracking, 'eating' glazes, but the pieces that do turn out are just gorgeous. Unglazed Cassius pieces look unusual and finished. I enjoy the bizarre things it does, like resulting in colorful mossy or wrinkled glazed surfaces. With sculpture or modern jewelry pieces you can get some really cool effects. Using brightly colored underglaze over white slip-painted areas creates dramatic jewel tones that stand out beautifully against  black left showing. To my eyes it's a lot like painting on a black velvet canvas. 

Share this post


Link to post
Share on other sites

Just wanted to share my experience with Cassius Basaltic.  Most glazes end up with pin holing, bloating, or just ugly on the surface on anything Cassius I do.  However, I've found that our studio's "licorice" and "blue hare's fur" work great on the surface as do most underglazes after bisque (not sure about greenware, haven't tested applying at that stage).  Here are some shots of underglazed vases with licorice inside and a cup coated in BHF.

Cassius Vases with Underglaze

Cassius Mug with Blue Hare's Fur

Share this post


Link to post
Share on other sites

Did I mention that the raw black clay (PSH) attracts a magnet? Hilarious- a leather hard item with a magnet sticking on the side- so... the iron is Magnetite or Fe3O4. After firing to cone 6, it turns brown - a very dark brown and is no longer magnetic so the iron is altered to hematite Fe2O3. 

My kilns are old fashioned- electric with a kiln sitter and gas caternary arch- no computers here except this laptop! So maybe one day when I have time, I will try bisquing to a higher temperature as I have no "hold" capabilities. 

post-67248-0-76771000-1485393812_thumb.jpg

post-67248-0-16361600-1485393945_thumb.jpg

post-67248-0-76771000-1485393812_thumb.jpg

post-67248-0-16361600-1485393945_thumb.jpg

Share this post


Link to post
Share on other sites

for some cultures though black clay is the norm isnt it? i have a particular fondness for danish pottery. esp. the potters island. all the photos i have seen and movies - (yeah i look at their dirt) seems like they have black volcanic soil. most of their pottery is dark clay. 

Share this post


Link to post
Share on other sites

Thanks, Nerd!  The owner of the studio I attend does all the firing, so I'll run the schedule by her to see if she can accommodate.  I also just received new switches for the used kiln I purchased, so I should be able to give it a shot on my own soon!

Share this post


Link to post
Share on other sites

"Just wanted to share my experience with Cassius Basaltic. Most glazes end up with pin holing, bloating, or just ugly on the surface on anything Cassius I do. "

 

Try firing Cassius to cone 5, not cone 6. Also, avoid stacking during bisque so all of the surface areas have room to outgas.

 

You can also reduce Cassius to a slip, then apply it to white or other clays. You get the black to work glazes with, but not the clay body issues.

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
Sign in to follow this  

×

Important Information

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