How To Temper Wild Clay
What is Temper?
Types Of Temper
Grog
The first type of Temper is grog. Grog is most commonly understood to be fired pottery pieces that have been crushed into a fine granular powder. Grog has similar attributes to sand in that both help with thermal shock, rigidity of your vessel and less shrinkage. One reason that potters may prefer grog to sand is that grog can be made from failed pottery firings. This is an easy way to access temper, and you can always get finer particles of grog than you can with sand.
To make grog, find a piece of pottery that has been fired, but has cracked or shattered due to a faulty firing. This pottery should have been fired to bisque, or around the sintering/vitrification temperature depending on the clay body. After finding a suitable piece to use as grog, begin crushing or grinding the pottery until it is made into a fine powder. Use whatever means are at your disposal that still ensures your safety.
After crushing into a fine powder, you can either use as is or sift the material with a meshed strainer, sieve or some other means until it is to your liking.
Sand
Silica sand can be found on river banks, lake and sea shores and even your own back yard if the environment is right. Soil and dirt is more common than pure silica sand in your back yard. With silica sand you may not find anything growing in that area, as pure silica sand has been striped of many of the minerals that organic life needs to live and thrive. Below you will see a picture of what temper should NOT look like.
How To Add Temper To Your Wild Clay
The first step is to break up the clay you are wanting to temper into 4 identical groups. To do this simply roll your clay into a thick cylinder that is even and consistent through out, and then cut it in half. After cutting the cylinder in half, take the two halves that you have and cut them in half as well. This should give you 4 even pieces.
The next step is to find the right portion of temper to add. For this recipe, use 20% temper to 80% clay. To do this simply bring your grog or sand into a compact pile and place one of your clay sections beside it. This will give you a round about idea of how much temper you have and if you need to add more or take some away.
The final step is to add the temper into your clay. To do this simply lay the temper out flay and wedge your clay on top of the temper. You may need to add water periodically during this phase to keep your clay from cracking while you wedge.
Finished!
