Potters & Sculptors - Making Rock from Mud
In this month's Digitalfire Newsletter Tony Hansen suggests a Silky Matte Glaze which resists cutlery marks can be made from a combination of:
90% Silky Matte G2934 (which leaves cutlery marks)
10% Gloss Clear G2926B (the addition of this clear glaze makes the surface smooth enough to resist marks from metal)
Using Digitalfire I've combined the two glaze recipes into a single 90/10 combination.
Then I've reworked the resulting glaze with two frits into two different single-firt versions:
a Ferro Frit 3134 version and
a Ferro Frit 3124 version.
An almost infinite number of alternate solutions can be created. Click on the screen-shot to see it Full-Size.
Were your results mark free? Because I have tried this before and I still got marks. Not to say that it wasn't my firing schedule that was the problem. Of course I probably could have spent more time with it to get it scratch free.
Tony Hansen's new Silky Matte is much harder than cutlery.
So I can easily make cutlery marks on the glaze, because the cutlery metal is softer, but the marks wipe-off the smooth surface with water, your finger or food.
The glaze was originally slightly more crystallized and matte on the surface, so the metal rubbed-off from the cutlery got bound up with the glaze surface and was tough to clean off.
A glossy hard glaze creates the same temporary cutlery marks, which are difficult to see with the naked eye because they're much smaller as the friction between the glaze and the metal is far less.
So basically any glaze that leaves marks that wipes off is pretty much durable as a glossy then? Cause I have a few mattes that I can rub a fork or butter knife over and get marks, but then I can easily wash them off in the sink/dishwasher.
I think I was confused by the difference.
Yes. unless you can create a magic frictionless surface either the metal will wear-off on the glaze or, much worse, the glaze will be damaged by the cutlery. The problem is a surface which is matte in a way which retains the worn-off metal.
It's like the moment I realized Witness Cones need to be protected from direct radiance from the heating elements.
The Cone 03 flattened because it was in direct line of sight with the elements, but the 03 witness cone protected the Cone 04 witness cone from the radiance, so it bent to a perfect 04. To get a true Witness Cone reading in an electric kiln I place ware between the elements and the witness cones.
Interesting stuff as normal Norm. Thanks for the replies.
Norm, I like your test. Have a question on the amt of epk used vs calcined glomax. I have always tried to keep my raw clay at about 10% or less and use about 90% of the balance of raw clay in glomax. Do you see any reason not to lower the raw clay to 10%
I can't think of a reason you can't reduce the amount of kaolin to 10% by replacing it with calcined kaolin (glomax).
I'm curious about your reason for maintaining 10%. Does this make each glaze more similar in application?
When I run across glaze recipes with 20% kaolin and also call for 2% bentonite I've often wondered how that came to be and will rework the recipe.
just a arbitrary number that seems to work in most glazes. More than 10% raw clay seems to invite mud cracking look and some glazes fall off. I want enough clay to keep it from settling and keep it easy to dip.