Over the last few months I have been fighting with my green glaze. I love it’s finished appearance but having made it up according to the recipe I had been fighting with it every time I needed to use it.


In only 24 hours it would completely settle to a very hard and heavy residue at the bottom – and after a few weeks it would separate to the extent that the bottom was completely dry! We think this is what the phrase “hard-panning” means and it is not good! It would take me around 45 minutes of very heavy mixing complete with splashing and cursing to get it into a workable solution – so everyone in the studio knew when it was on the table.

One time I decided to dry cutting it into smaller chunks with a knife so it would be easier to get up and mix – and ended up cutting right through the bucket causing a lovely leaking mess.

A couple of people had mentioned adding 1% bentonite to a recipe to make it easier to mix, so I tried this. It did help, but not enough so I added more. In the end a total of 3%.

The mix is now MUCH easier to work with. It separates a little, but the bulk of it stays as a kind of heavy moussy mix that is easily re-stirred.

2013-07-04 17.00.49

2013-07-04 17.01.11

The resulting glaze is more viscous at the application stage, so tends to go on thicker, which is fine for this glaze as it needs a good application to get a decent colour and crystallisation. It also seems to be making the copper green of the finished glaze a bit darker, and making the glaze runnier in the kiln, though I’ve only lost one piece to the kiln shelf so far.

I will be re-testing application thicknesses over the coming weeks, but in the meantime I am in love with the easy-mix results!


2 thoughts on “Ode to Bentonite

  1. Lovely glaze Jane!
    I also love Bentonite. I add it to a lot of glazes that are low in clay, so they stay suspended. I have gone to 5%: when I went higher, I got a kind of jelly-like texture and had to whack narrow vases to get it out – like ketchup out of a bottle… not ideal!

    • Thanks Carys, it’s good to know you can add even more, everything I consulted suggested only 1% and it did make me wonder what would happen if I added more than that, I guess they are trying to avoid the ketchup effect!

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