Thursday, October 9, 2014

Chalices for Communion sets, my way

There are a couple of ways to make goblets and chalices that I have seen and tried. Some potters make goblet type cups by throwing a cup on top of a solid piece of clay shaped like a stem. These are usually heavy as they get larger. I have seen some of these where the potter will turn it up side down and trim out part of the stem by hand or while on the wheel. I have also seen and tried throwing a cylinder, choking it for a cup at the top and adding a small ball of clay into the cup to seal it completely. Other potters will throw the cup and the stem in two pieces, which is the way I have come to make the chalices that I have been creating for over 30 years.

So the first thing that has to be done in this technique is to throw the bowls, and the stems. I throw these off of a large hump of clay usually 15 to 20 at a time. I throw all of the cups first, then the stems.
This usually takes a morning to get them all finished up. Then they have to dry until what potters would call cheese hard. Cheese hard is a state where a finger will indent the clay, like cheese, and a slab of clay will be able to be held out by one end without slumping completely just slightly bending. It is just before leather hard where the clay is stiff, not able to be impressed with a finger, but a finger nail will. Usually pots are trimmed when leather hard. I start at cheese hard on the stems to make it easier to trim in the chuck for leveling the bottom and removing a little hole in the center of the stem base.
A few years back, I created a chuck out of some plumbing parts that works quite well with my Griffin Grip (gp). I use this to trim almost all of the pots that I make preferring it over the many other methods I have used in the past. These include thrown chucks, damp wheel heads, clay chocks on the wheel head an piece, and many others.
I start my trimming of the base with a good hack saw blade that has not had edges worn down. This helps me to level out the base. Then I use a needle tool to trim out the center of the base so as not to have a trapped air pocket. I do not worry about the piece blowing up from trapped air, but it does stress joins and could crack them.
I finish the stem with a signature and a letter stamp "R". Most of my stems have a base in them, but occasionally they will just be an open stem. Then turning the stem right side up add any decoration that might seem warranted. This is just rough trimming as the clay is still a little damp, but later the sides will get more cleanup and definition. I like contrasting areas of smooth and valleys for glaze to pool in as much more happens when they are there.
Once the stems have all been trimmed, usually two hours for twenty, I will move on to the cups.

By now the cups have set up to nearly leather hard so joining the two together is pretty safe without distorting the cups in the gp. An old trimjim tool is my trimming tool of choice but almost any trimming tool will work, I trim the cup with the stem diameter in mind so that the stem fits into a hollow on the underside of the cup, then I burnish the two together as the clay is still a little damp and the added water from the joining. I use magic water (1 gallon of water,3 table spoons of liquid sodium silicate, and 1 1/2 teaspoons of soda ash) to join these together added on with a stiff cone shaped brush. This will score the area a bit, and make a little clay mixed into the magic water to fill gaps.

Once the chalices have been completed they are left to set up until completely leather hard and then cleaned up by additional trimming and hand rubbing with a soft sponge. This will remove the nerds and ditties (little pieces of clay) from the sides of the piece and smooth up any unwanted gouges.

bats full of chalices
Chalices are ready for firing, but at the same time 20 of these does not make a load, just as a few bowls, some canisters and other pieces does not either, but altogether they will fill the kiln.
New canisters to be completed.

Kiln inside with bowl and bird bath
Here is a view of the inside of my L&L kiln that I have had for over 25 years. I fire with no kiln setter, just cone packs to check on the temperature of my firings. This does mean baby sitting the kiln for 12 hours usually, but I have been doing this for a long time. Kiln firing this weekend!