To Make or Buy: First, let’s discuss why you would make your own paperclay when you can buy it. Although some people don’t have a local source, if you are near a metropolitan area with a large ceramic supplier, chances are they will carry paperclay. However, making paper clay allows you to control the proportion of clay versus paper, the kind of paper, and the clay body. Use clay scraps or old clay that other people give you to reduce the cost. Also, you get a nice slip that can be used for unconventional construction methods requiring slip. Personally, I do both (make my own and buy commercial paperclay).
Materials to Make Your Own Paperclay:
Any clay body, dry to be made into slip, or slip. I prefer a body without grog or only a small amount of very fine grog.
Strong drill and paint mixer or plaster-mixer on the drill with blades.
Large metal or plastic container for paper mixing
Lots of buckets
Strainer (like food strainers)
Paper: Shredded office paper or shredded “brochure” stock is OK. Brochure stock that is very matt and tears easily is good. Cotton Blotter paper. Any paper that breaks down fast in water. The easiest is toilet paper, but it molds quickly. Cellulose insulation has preservative that fluxes body a little, but is slightly slower to mold. Cotton Linter (used by paper makers) seems to mold less.
Method:
Work in an area where you can clean up paper and clay splatters.
Prepare clay slip: If wet, dry it out and break up into 1-2” chunks. Add hot water, let sit, mix with paint mixer until smooth. I mix slightly less than ½ bucket of slip. See measurement chart below.
Prepare paper pulp: Put very, very hot water into large container (30 gal). Add paper and let sit to break down. Add anti-mold cleaner or 409 (1/4c or less per large container). Run dry-wall mixer in container until paper is a “cloud”
Use strainers to strain water out of paper, but don’t compress the paper pulp. Put the pulp in the slip bucket and mix it periodically with the paint mixer. Fill til bucket is about ¾ full. The clay will have a slightly lumpy appearance. Try to make it as smooth as possible. The secret is to make sure the paper is well broken down into a “cloud” so that no individual pieces of paper can be seen. Also, mix frequently and well when adding pulp to clay and do not let pulp get compressed or dried out.
Pour mix out on to large plaster bats.
Lift and wedge when just dry enough to hold together. Or, use slip for other construction methods.
This makes paper clay that is about 30-40% paper by volume. Change proportion of slip and clay for other purposes. Use a ruler sunk into the slip before/after adding pulp to measure volume of clay and pulp.
Measuring Paper/Clay Proportions When You Are Making Paper Clay:
You can either make it by the wet volume measure or by the dry weight measure. The dry weight measure is more accurate, but takes more time. Below is a reference I have developed by doing it both ways and showing the level in a 5 gallon bucket.
1 ounce = 28.35 grams
1 pound = 453.6 grams
20% pulp by volume = 2.5% dry weight
6” slip in bucket (20 pounds dry clay/9072 gms). Add wet paper pulp (8oz/226.8g dry paper) until 7.5”
32% pulp by volume = 3.7% dry weight
8” slip in bucket (25 pounds dry clay/11340 gms). Add wet paper pulp (14.8oz/420g dry paper) until 11.5”
Here is a download of the entire handout on paperclay including why use paper clay, techniques, how to make paperclay, and references.