Crater Test Series

Here are some Crater Glaze Tests with stains.

The recipe is Pinnell Strontium Matte at cone 6 E1 firing

60 Nepheline Syenite

20 Strontium Carbonate

1 Lithium Carbonate

10 Ball Clay–Old Mine #4

9 Silica

100 Total


5 Titanium Dioxide
2.5 %  Silicon Carbide 600 M

Apply VERY thick. And you can add up to 5% silicon carbide. You can also vary the amount of stains. See page 178 in The Complete Guide to Mid-Range Glazes for more recipes and firing information. Electric E1 cycle. This can vary too!!

This last one is Mason 6433 at 5%, 10%, 15%, 20%, and 25%


Linda Starr said…
love the first one with the lavender color, one of my favorite colors, craters on the others are nice too.
Unknown said…
Hi! Did you know some low fire crater glaze?
John Britt said…
You can just try matte low fire glaze....I can look tomorrow.
John Britt said…
You can just try matte low fire glaze....I can look tomorrow.
John Britt said…
Here is one:
Beth Tate said…
Struggling with crater effect, anyone have a firing schedule they can share?
John Britt said…
I use E1 from my book on midrange glazes, which is just fast fire. (you don't want slow fire because all the silicon carbide will burn up. You want to catch it burning up and leaving bubbles. It is basically 200 F per hour to 200 F, hold 15 minutes to dry glazes, then 500 F per hour to 1978 then 150 per hour to 2225 F.
John Britt said…
There is a good Facebook Group you may like:
Beth Tate said…
Just ordered your book. Yay!
so one last question, if you dont mind….

---do slow ramp down between 1900 and 1500 for a matt effect? (Am working with Steve’s Strontium C6 glaze from Lana Wilson’s book.)

Have been successful in getting a cratered look by heavily texturing the pot when throwing and not quite covering everybody up.

Feels a bit like a cheat though. Hence this new path down crater glazes.
Unknown said…
Hello John,
concerning the silicon carbide, you wrote 600M.
Is it the grain size ?
And where do you buy it. I found on eBay a Grit-400 (grain size) silicon carbide from England by Minerals Water.
By the way I am from France.

Thank you for your answer.
John Britt said…
I don't know where to get it in France. Call your ceramic supplier. Or there are potters using it like Jan Lewin Cadagon (in england)
and they may have leads:
Unknown said…
Ericad said…
Hello there,
Do you remember if you included the additives in your tests? I'm very into the textures and craters, but I'm not sure if I should include the titanium dioxide or the silicon carbide. Thanks!
John Britt said…
Yes. You must add silicon carbide 600 mesh and titanium plus what is listed in photo...Burnt Umber 5%,etc.
Unknown said…
is the Pinnell Strontium Crater cone6 oxidation food safe?
Unknown said…
Can you tell me how nuclear and temperature procedures are ?
Thank you
John Britt said…
Fast fire 2232 cone 6