In search for a true red

Dec 31

Since I've started making glazes there have been a few goals I set for myself. Making a Hyacinth, a good black, a good liner glaze, a version of my own glaze that people can use, at least five main goals in total. The one thing that I dream of is getting a good red glaze in oxidation. This want has been something on my main glaze experiment line for so long that I had finally given up and decided to take a real class on glazes chemistry.

The class was taught by a man named Matt Katz. Before this class I essentially only knew how to put together glazes much like a cook following a recipe, of course I know a lot of the tricks that come along with making a good glaze, The problem is without the underlying chemistry and understanding a lot of the heat work that goes into the chemical reactions that make colors and stability I wasn't going to get anywhere near my goal of making a red. SO i bit the bullet and after a month I completed the class. Now armed with the knowledge of this glaze course I have a good sense of what direction to go in as far as the missing steps that were needed to make a good iron saturation red. Even more, other people have been down this path before so I'm not completely lost.

This is a very long way of talking about my most recent experiments.

(From left to right) All glazes will be put at 1800 degrees f for an hour hold. I'm told this helps develop reds.

The first test is the tried and true Randy's red but with g200 EU feldspar instead of minspar 200. I know most g200s are discontinued but I have a very large stock of it left and I consider it a higher performing, cleaner version of Custer feldspar. If I can replace any Custer Felspar with a g200 I'm going to do it. I don't consider minspar to be bad at all, it being chemically close to KonaF4, but I still want to see the difference. The last modification I made is instead of using R.I.O i am using Y.IO. This is the case in most of these experiments.
Experiment number two is an extremely simple glaze I found on glazy.org that promises a good red and has extremely simple chemistry. It's literally five ingredients and two colorants. It's called red/gold. The glaze had no picture and that's what prompted me to test it. Its a revision of a shaner glaze. i see no bone ash (which most of the reds i am looking at have). I’ll be very very surprised to see this glaze work out.
the glaze >>>>>> https://glazy.org/materials/1478
Glaze number 3 is special one. lot of us on the discord have been talking about the water solubility of lithium carbonate and whether it's actually doing any work in the glaze or not as most of it travels with the water into the bisque clay body instead of staying with the glaze where it belongs. One person even noted that it's about 1.4 to 1.5 water solubility per every 100 ml of water. Considering that I do not use 100 ml of water per 100 g of glaze ( i like my glazes to be a bit thicker) this means that at least 3/4 of it is staying in the water instead of being suspended in the glaze where it belongs. There are two different versions of this glaze, one of them is with lithium carbonate and the other one works on the chemistry with Spodumene as a lithium replacement. I have already tested the one with carbonate and it seems to work fine especially when you let it dry and double layer it( see picture to right) . This test is a revised version of that glaze just to see if it works out without the double layering or if it works out better at all. Even if it works out the same that would be sufficient enough to say that I can replace lithium carbonate with Spodumene by working around the chemistry.
(P.s) I'm so convinced that lithium carbonate isn’t doing the amount of work it needs to that I often wait for my glaze to dry and double dip any glaze with lithium carbonate in it. My theory is at the first dip fills the bisque pours enough so that no more lithium carbonate travels into the clay body, meaning that the second layer will actually get lithium carbonate on top of the glaze and not in the clay body, I noticed this with at least three of my glazes)
The fourth experiment is a suggested glaze from coneInfinity https://www.instagram.com/coneinfinity/ (his Instagram handle) who was citing research from Derek AU on reaching good reds and oxidation. It seems that Derek has already done a lot of the research on this. The difference with this experiment is that his glazes are often at cone 10 and 11 while this test all the way on the right is going to be at cone 6 oxidation. I'm slowly learning through my glazed chemistry courses that cones are not real…. In a sense. Only the heat work to make the chemicals react matters. There are tons of recipes that are supposed to be for cone 4 or 5 that you can take up to 10 and get fantastic results and vice versa. This is prompting me to take a lot of cone 10 glazes, reduce the amount of alumina and silica, work the chemistry around a bit, and make them into cone six but it never hurts to test the recipe straight out. The main difference with the glaze is that I'm testing it with g200 EU feldspar and a Red iron oxide substitution called Crocus Martus. In my experience this is either a good substitute for red iron oxide or it comes out way better.
The original glaze >>> https://glazy.org/recipes/25001

3 things I have learned