Ever come across some clay while on some outdoor adventure and wish you could make some pottery out of it? You can. I love working with clay and have experimented with both a pit kiln and firing pieces over coals of a campfire. Below are tips on the whole process from finding clay to firing your primitive pottery.
This summer I held a workshop for children which included making pinch pots from locally dug clay.
Here are some of the pieces my students made.
This is what they looked like before being fired.
Finding clay and getting it ready to use
You can often find clay along the banks of a river or stream. You can sometimes find it on local beaches. Look for gray or red stuff that clumps when you squeeze it in your hand. When wet, it should also feel slippery. You might also find it dry.
Bring along a container. Gather clay while trying to avoid surrounding soil.
Fill the container about halfway with clay and then fill the remainder with clean water. Remove rocks and sticks and other organic matter. Break up the clumps and mix until completely dissolved. Your mixture is called slip. If you collected dry clay, pound with mortar, reconstitute.
Put a screen (can be made out of hardware cloth or purchased) on the top of a clean bucket. I made a screen out of a wood frame with stapled wire window screen. Pour your slip into the bucket. The screen will take out any unwanted stuff. If after screening it still feels too gritty (sandy), you can strain it again through an old tee-shirt.
Let it settle
Let the clay settle to the bottom. Scoop or pour off the clear water
When it is thick enough, put it on a piece of wood to dry in the sun. The wood helps to absorb the excess water in the clay. Check your clay during this drying time because you don’t want it to become too dry. When the clay is the right consistency to use, scrap it up and put in a plastic bag and seal. Your clay will be even better to use if you wait a couple of weeks.
Wedge and knead the clay before using. You may need to add temper (sand, grit, shell, grog (broken pottery), etc. Add 1/5 -1/3 temper, knead, and wedge. Temper is used to open the pores and make them less likely to crack when subjected to heat. Also reduces shrinkage and warping during drying and firing. This is especially important for large pieces.
3-10 days, depending on the piece and temperature and humidity etc.
Dig a pit with sloping sides about 2 feet in diameter and about eighteen inches deep in the middle. This fits the standard round barbecue grill but you can make your hole to accommodate the amount of material you wish to fire. Find a place to put your pit that is away from trees or other plants that could catch on fire. Next, place a three inch deep layer of sawdust and or manure in the bottom. Put the oven rack on top of this layer. Again, you can adjust your design to accommodate your needs. Then arrange the pieces to be fired on the rack so that there is at least one inch of space around all sides of each piece. Fill any bowls or other containers with sawdust. If there are too may pieces on the rack, you can cover the pieces on the rack with more sawdust (4 inch layer). Remember to put the heavier pieces on the bottom to help avoid breakage. Now cover the pieces with at least twelve inches or more of sawdust. You should fill your pit completely. Add twisted pieces of newspaper in a thin layer. These are to be used to set the fire. Place a cover (like an old trashcan lid) to cover the top of the pit. Place some rocks under the edges of the sides of the lid to hold up the cover and allow air to get in. Light the newspaper. After it is burning well, put the cover on. Flames will come out the gaps for a little while and then you should only see smoke. If the smoke soon stops you should relight. Let the pit kiln burn over-night or at least for 6 to 7 hours. It isn’t necessary to stay with the pit the entire time it is burning. Once the flames have died down, it’s safe to leave. For safety, you may choose to post a warning sign. When the firing is completed, remove the lid carefully (it may still be hot). You could use a potholder or a stick. Carefully dig through the ashes to find your pieces.
Firing in Campfire
Place the pieces on a bed of hot coals. Experiment with the placement of your pieces to determine what will give you the best results. I let the fire go out naturally before taking them out of the ashes. Taking the pieces out while really hot can cause them to crack if they cool too quickly.
Obtained information from experience and from:
Make it in Clay 2nd edition by f. Speight and J. Toki.
The Kids ‘N’ Clay Ceramics Book created by Kevin Nierman and written be E. Arima. This is a nice book that has a lot of cool kid project ideas.
Nature Crafts for Kids: 50 Fantastic Thinks To Make With Mother Nature’s Help. By G. Diehn and Terry Krautwurst.
Science Crafts for Kids: 50 Fantastic Things To Invent and Create. By Gwen Diehn and Terry Krautwurst.