Patina Revisited and a Source for Lids

Underlying Assumptions

There are two underlying assumptions that I detect in many of the emails that are addressed to me with questions. The first is that coconut carbon does not result in colorful pieces; the second is that if pieces are colored, that necessarily indicates that they are well sintered.

I am not sure at all that these assumptions are accurate. Here are some results from tests that I’ve been doing recently.

The following two photos show pieces that have been fired with coconut-based carbon. They are all well sintered.

The following photo also shows pieces that were fired in coconut-based carbon.

In spite of the colors, they all broke easily.

The square pieces in the following photo were fired in coconut-based carbon, at the center of the box. As you can see, they have better colors than the pieces lined up along the sides of the box. However, these, too, did not sinter.

The one thing common to all the colored pieces shown in these photos is that they were taken out of the box while very hot.

About the Lid

In one of my postings I mentioned that I do not use the lid that comes with the stainless steel firing box because it takes up too much space, both inside the box and in the kiln chamber. I use stainless steel sheet, 28 gauge. It comes 6” x 12”, and when I cut it in half (using just scissors) it makes two perfectly sized lids. I have been able to find this sheet at a local Ace Hardware store, but many local stores don’t carry it.

So here is an online source:, and this is the item: (scroll down to the item before last). As you can see, KS Metals also have tubes that can be used as cutters and as molds for clay tubes. They only sell to retail stores, but on their site you can find a local store locator: .

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