When I make a new pot (a new design or different form), I consider several things:
- Glazes (yes, this is a consideration from the beginning)
- Pot function
- Pot scale
- Foot, rim, and appendages
Part of the design process is working out the logistics; and, taking notes makes it easier to keep track of those logistics. In order to make pots efficiently, I need to know some basic stats (weight and size). And, as I don’t remember details well, I keep the information corralled in a notebook. For me, this one of the most important parts of developing/designing a pot. For example, last year, when I made several dessert plates, I developed a ‘recipe’.
First I started with the ending in mind. I wanted a finished plate with a diameter of 6”; so I used the LidMaster calipers (set on the 12% shrinkage scale) to determine that I needed to throw the plate approximately 6 ¾” in diameter. I weighed 3 balls of clay – 1.25 lb, 1.5 lb, and 1.75 lb. After throwing each plate to the same dimensions, I found 1.5 lbs to be an appropriate amount of clay for a plate with a foot ring. Then I edited my notes and I continue to use them as a reference.
However, yesterday while I was making dessert plates according to my recipe, I realized I had too much clay to make the size plates I usually make. I felt like the rims were too wide with 1.5 lbs. So I reduced the clay by 2 ounces and all came out well.
It is true that very soft (moist) or hard (dry) clay will affect your throwing efficiency. But the larger factor is often throwing ability. As throwing efficiency improves (i.e. you use the clay rather than leaving it in the bottom of the pot), pots will get larger. So the large bowl that you used to make with 5 lbs, you can make with only 4 lbs. This is a huge step in your development as a potter.