Ode to the chemical guru’s on the internet:
I was wondering if you might be able to help shed some light on some glaze issues or at least point me in a direction for research. We inherited a lot of recipes when we opened out studio 3 years ago, I want to better understand the glaze making process, food safe, base glazes, and why we seeing some of the results during the last 3 years. I have been dabbling with it during the course of the years, but not seriously until now. We do cone 6 oxidation firing.
Firstly I am playing with alberta slip and wanted to manipulate some of the recipes to get the kind of variegated blue/brown like in the photos on your article about alberta slip (80 alberta, 20 frit 3134 plus 4% rutile). I did get variations in color and crystals, but the hues were mostly brown to slightly olive in color ( I have pictures if you want to see http://www.flickr.com/photos/miyceramics/4789406114/) or here for the set(http://www.flickr.com/photos/miyceramics/sets/72157624487133222/)
Secondly. We also have a lime glaze based on your 5 20’s(silica, dolomite,spodumene, om4, f3134) recipe with Rutile, tin, and copper carb that has always misbehaved and looked yellow instead of green. I fixed it and made it more green by doubling the copper carb, but it is nowhere near what it should look like.
Thirdly Our floating blue recipe using gerstly borate which is just like your 2826R recipe on your site comes out more green than blue.
We also just mixed the mc6g Glossy Liner 2 and added 5% rutile to it. We got some variation, but it was mostly clear and white like the clay boday. So maybe the rutile is not high in iron…. (http://www.flickr.com/photos/miyceramics/4788774345/in/set-72157624487133222/)
I suspect it is my rutile, but I can’t find anything to corroborate that though. Any mention of rutile blue anywhere in the internet talks about reduction. Could it be the batch of rutile I have is low in titanium and high in iron and that is why I don’t get the blues? Before I understood anything I also bought some dark rutile several months ago, but now after reading up on some of the articles on digital fire I realize this won’t solve the issue.
If you can point me in direction at all I would appreciate it.