Help: Advice on pumice bubble surface finish

[projectspace]

I'm trying to create an unglazed tile with a bubbly pumice surface finish. I was thinking of using a sponge, beads, or poking holes, but none of those would make true 'bubbles'.

Here's a perfect perfect example of the finish I'm looking to do:


Any advice?

[Andy Clift]

I've got a similar texture by hitting the clay over and over again with a large wired brush.

[projectspace]

I've got a similar texture by hitting the clay over and over again with a large wired brush.

Thanks for the response Andy!

After digging in further, I found out the effect is called "cratering" (google image search for "crater glaze"). Looks like I need a glaze with large particles of Silicone Carbide.

Now I have to figure out whether I can do this glazeless. Wondering if I can just use a Silicone Carbide slip.