On a throwing morning the first thing I touch is not the wheel. It is the scale. By nine o'clock there are usually thirty-six balls of clay lined up along the wedging bench in rows of six, each one weighed to 420 grams and patted into a rough cone so it sits on the wheel head the same way every time. If the scale says 423, I pinch three grams off and drop them in the reclaim bucket. If it says 417, I find three grams.
People who watch the long videos ask about this more than anything else: do I really weigh every single one? Yes. And the reason is not perfectionism. It is that the scale makes most of the decisions for me, so my hands are free for the ones that matter.
What the scale decides
A mug is a set of small agreements. The height has to agree with the handle you are going to pull for it. The width of the rim has to agree with a mouth. The weight in the hand has to agree with what the eye expects when it sees the shape, because a mug that looks sturdy and feels light reads as cheap, and a mug that looks delicate and feels heavy reads as a mistake. When I start every mug with the same amount of clay, half of those agreements are settled before the wheel turns. I am not trying to hit a height with an unknown quantity of material; I am spending a known budget.
It also makes sets possible. Most of what I sell goes out in sixes and fours, to people who want their mugs to stack and to look like they belong to each other without being stamped out of a factory. You can throw six matching mugs by eye. It takes about twice as long, because you spend the whole session comparing the one on the wheel with the five on the board, and the sixth always comes out a centimetre taller anyway.
And it makes the work honest about itself. When a mug goes wrong, the scale removes one suspect. If the walls came out thick, it was not that I started with too much clay. It was that I did not pull it up far enough, and I need to look at my hands rather than the bench.
I am not trying to hit a height with an unknown quantity of material. I am spending a known budget.
Where the 420 grams go
Very little of that ball ends up in your hand. Throwing takes some of it as slurry that runs off my fingers and gets scraped back into the reclaim bucket. Trimming takes more: when the mug is leather-hard I turn it upside down and carve the foot ring, and the curls of clay that come off the base weigh somewhere between sixty and eighty grams. Then the water goes. Wet stoneware is a good part water by weight, and the mug loses all of that drying on the shelf and the rest in the bisque firing. By the time it comes out of the glaze kiln it has also shrunk, by roughly an eighth in every direction, which is why the mugs on my board always look slightly too big to anyone visiting the studio for the first time.
The number 420 is not magic. It came out of about a month of throwing mugs at 380, 400, 420 and 450 grams in 2021, writing the finished height and capacity on the base in pencil, and living with them. 380 made a cup I liked for espresso people and nobody else. 450 made a mug that was a pleasure to hold full and a nuisance to lift empty. 420 was the one that I kept reaching for in my own kitchen, which is the only test I fully trust.
When I ignore the scale
Bottles and the larger bowls are weighed too, but only so I can repeat them. The one-off pieces are not weighed at all. When I sit down to throw a big jar for a kiln-opening sale, I want the clay to tell me how big it would like to be, and I want room to be wrong. Some of those pieces are the best things I make. Most of the worst things I make are also in that category, which is fine. That is what the reclaim bucket is for.
There is a version of this job that is all improvisation, and a version that is all repetition, and the long videos are really about the space between them. If you watch one of the forty-minute ones, you will see me throw the same mug twelve times. You will also see that none of them is quite the same, and that is the bit I cannot weigh.
Tomorrow there are thirty-six more on the bench. Thirty-five of them will weigh 420 grams. One of them always comes out at 426, and I have never once worked out how.
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