Oh Grog!

This year’s throwing season seems to be going well! Very minimal mistakes plus,thanks to learning about an alternative way to take large pots off the bat, I have been able to throw larger pieces: plates, serving bowls, platters and pet bowls! To date, I have thrown over 35 pieces since Memorial Day! 😀

Unfortunately, I’m having trouble with grog ruining my pieces. Oh Grog!

What is grog, you ask?

Well, in the pottery world, it is not an alcoholic beverage although after seeing this grog ruin my several of my pieces, a stiff drink of grog may help ease my disappointment. It is also not a fictional character found in graphic novels, role playing games or computer games. Nope. The grog that pains me can be a combination of fired clay, silica, sand and feldspar all of which are ground to various sizes and added to clay. The propose of grog added to clay is to improve “ drying performance, reduce drying shrinkage, improve fired abrasion resistance, reduce thermal expansion, reduce fired shrinkage, reduce density, impart visual character, etc.”

Grog in various particle sizes added to clay to decrease shrinkage among other things. The above image is from digitalfire.com.

In years past, the particle size has been fine enough for me not to notice. This year, however, this particle size is causing a problem.

A large piece of grog causing a pit in my freshly thrown platter not yet fired.

This piece was bisque fired and glazed all to be ruined by a piece of grog causing a pit.

I plan to call my clay supplier to ask if anyone else is having the same issue with this clay – the same clay I have been using for years and never had a problem with grog until now.

In the meantime, I decided to mix my groggy clay with a lighter non-groggy clay in the hopes of adding more plasticity and minimizing the effect of the large particle grog.