DIY Shrinkage Rule

One of the tricky things about making pots is that clay shrinks as it dries and fires. It is not all that bothersome until you have a custom order for mugs that need to be a specific height and diameter or you drop a casserole lid while unloading a too hot kiln.

10% Shrinkage Rule next to a standard ruler

 Whenever I have needed a pot of a specific size, I have sat done and done the math and then  proceeded to make the pot to the size I computed. This works fine, but is time consuming when done over and over. Finally, as I walked out the door to go to Highwater Clays, Alex said, "Honey? Why don't you just buy a shrinkage ruler?" He's brilliant, I tell you!

But I got to Highwater and they were all out of shrinkage rulers.  When I got home, I decided that since I could do the math, I should just sit down and make a shrinkage ruler specific to my clay.

We use Highwater's Speckled Brownstone, which has a shrinkage rate of 10%.

The first step is to subtract 10% from 100% giving us 90%. This means the size of a fired piece is 90% of the size of the thrown piece.
Convert 90% into decimal form, or .9.
Next we need to figure out what one fired inch equals in freshly thrown clay, so we'll divide 1 by .9, which equals 1.11. So, 1 fired inch equals 1.11 inches in wet clay.

Now we have enough information to create our ruler. I used a paint stick for my ruler. A) it is free. B) I have them laying around all over the studio. C) Did I mention free?

Now, I find it hard to figure out on a standard ruler exactly where 1.11 inches would fall, so I converted to centimeters. 1.11 inches equals 2.8cm. I marked my ruler down to quarter inch increments (every 7mm) using an ultra fine tip Sharpie marker.

I converted to metric to more easily mark my ruler.

Considering that most shrinkage rulers cost about $13 and this only took about 5 minutes to make, I think this was certainly worth my time.

Wabi-sabi Dishes

We've been creating some dishes with the wabi-sabi philosophy in mind. While not letting go of our ideals of good craftsmanship, we have tried to let the beauty of imperfection remain in this line of work. 

Wabi-sabi is often defined as "flawed beauty" or "wisdom in natural simplicity". 

Lined up on ware boards.

Glazed in Deep Lagoon.

Glazed in moss green.

Dropped Platters

Last month, we saw this article in Ceramic Arts Daily about making pottery using dropped slabs. We had done this sort of thing on a smaller scale (with shorter drops), but we wanted to try it as an alternative to pressing slabs into slump molds.

First, we created a variety of wooden frames. 

This set creates a large platter, a dinner plate, and a salad plate.

We placed a frame on a ware board. Ours are smooth plywood covered in a fine canvas that would normally be used for stretching your own painting canvases.

We lay the slab into the frame, gently lifting the edges so it begins to slump into the frame.

We hold the board with frame and slab about chest height, take a big breath.....

...and let go!

When it lands, the clay slumps into the frame. If a section doesn't quite slump, we'll lightly sponge it to press it into the frame or we will drop the slab again. Dropping again can warp the sides a bit because the slump farther. It is really cool that the edges usually trim themselves in the process!

This one was wiped with a sponge to get it completely in contact with the frame.

This is a finished plate!

This method is loads of fun and we laugh a lot while we make these! 

The plates are firing very flat and stacking very nicely. We are enjoying coming up with fun designs for the glazing.

Tree of Life

We've been enjoying working on relief tiles and plaques. Here is one before and after firing.

Joy Ride

Our work has suddenly veered off road! We are enjoying the ride with white knuckles and trying not to anticipate the road ahead beyond avoiding the next obstacle we see.

Work in progress:

Homemade Bat System

We have been looking at several bat systems that use a main bat and inserts, but didn't want to spend the money with so few reviews to go on. So, we decided to create our own bat system using upcycled materials.

First we started with a plastic bat like this:


Then, we marked a square, drilled a hole in one corner, and used a router to cut out a square. The router leaves rounded corners. Rather than going in with a scroll or hand saw and squaring the corners, we decided to take care of it on the inserts.




Next, we cut the inserts. We used Corian™ counter top material that was left over from sink cutouts at our local counter top fabricators. It is smooth, non-absorbent, and durable. These were cut to the same measurement as our cut-out bat. We clipped the corners which was initially done to avoid messing with the square in the main bat, but ended up being better when throwing as well.


We originally thought we would use the wrong side of the Corian™ because it has a little tooth, but we found we preferred throwing on the right side. The wrong side is not planed perfectly smooth and the wobble transferred to the clay.


Alex quickly whipped out stacks of inserts and we made them in 6 inch and 8 inch sizes.


The inserts are easy to remove from the main bat using any number of tools. When we designed the system, we thought the hole drilled in the corner would aid in popping the insert out, but we found that with the corners clipped, we can pop a tool under any corner and lift the insert out.


FAQs

Corian™?
Yup. We chose it because it is durable and waterproof and there is a lot of it headed to dumpsters. Upcycling is the new black.

I notice the insert sits higher than the bat. Is this a problem?
It hasn't been for us. Before using this system, we frequently used small, square bats. As long as we are using the right size insert for our piece, there is plenty of room for our hands.

Is it really easier to clip the corners of each insert rather than square out the corners of the bat?
Um... I don't know. It happened by serendipity and turned out to be a good thing. Now there are no hard corners to catch tools or hands!

How do you get the cutout centered?
Well, with the plastic bats, you can see the pin holes through the top. So, We marked a straight line across the bat through the pin holes. We found the center of that. Then we marked a line perpendicular to the first through the center. From there, it is fairly straightforward to mark a square that is centered on the bat.

Are you going to make these to sell?
We are considering it. Because we make sure each insert fits the bat perfectly, we are concerned it would be hard to supply more inserts at a later date. However, about 20 inserts fit in a flat rate Priority Mail box with a plastic bat... at least in the 6 inch size.

While the snow falls outside, it can become very difficult to motivate ourselves to throw at the wheel with cold, wet clay. On the coldest days, we crank up the kerosene heater and handbuild. This week, we spent some time with our extruder and created a shelf full of posey pillows.


Pen cushions or posey pillows are a bit of an indulgence in the studio. They are fun to make and invite us to explore new ideas. While they are labor intensive, they never seem to become a chore, probably because they end result is just fun!

Soon, the crocuses will begin peaking through the snow and we can fill our posey pillows up with the promise of spring! Here is a peek at some of the posey pillows to come:

If there is a better name for these, let us know. We have toyed with posey pillows, pen cushions, and pen-kebana. Many people use these on their desks to hold pens and pencils.

Finding Inspiration

At times, inspiration can be found everywhere we look; yet there are those dark days when the muses become quite elusive. There are a number of ways to make the muses linger such as keeping a journal or sketchbook, researching historic design, and our favorite... tuning in to the children around us.

We have had a harsh winter here in Appalachia. Our kids have been home from school more than they have gone and our studio time has been frequently interrupted. However, having the boys home has meant a continuous stream of creative ideas expressed without reservation.

Last week, the boys announced that our fish needed houses in their fish tank. "Great idea!", I said, so down to the studio we headed. We grabbed the essentials: clay, fettling knives, needle tools, and 'stinky glue' (paper clay slip).



We used the extruder to create the bodies of our houses. The boys attached them to 'yards', cut doorways and windows, and added roofs and chimneys. Boo even boarded over his windows after cutting them out, "in case there is a storm".



After the bisque and glaze firings, the boys' fish houses settled nicely into our aquarium. We have since decided that we need more houses and our doorways need to be just a bit larger. They also said we needed working chimneys so we can put a bubble stone in the house and bubbles will come out of the chimney.

As for my part in this, I was inspired to make these:



Mine won't be landing in the fish tank, but instead will land in our etsy shop.

Since school was called off again today, I am hoping they'll come up with another cool idea so we can all work together in the studio while the storm blows through.