Comments on: Getting Started with Crystalline Glazes

By: Chris Anderson

Chris Anderson — Mon, 30 Nov 2009 03:04:47 +0000

I have enjoyed your website very much. Fantastic work.

I am not a ceramicist. Rather I dabble in older photographic techniques and was wondering if it is possible to apply crystalline glazes to glass plates or other translucent sub-straights. I would appreciate your thoughts.

By: Kaitlyn

Kaitlyn — Fri, 23 Oct 2009 02:55:48 +0000

i actually had more of a question than a comment. i’m a high school student who’s trying to make a crystalline glaze for my school. now i’m not in control of the firings or anything like that my teacher does that, is there a basic crystalline glaze recipe that you would recommend that would work without a specific heating/cooling/holding temperatures for a certain amount of time? You see my dilema? do you have any suggestions?

By: Nazmul

Nazmul — Mon, 18 May 2009 05:46:00 +0000

I love your website. Planning to test my first crystal glazes soon. Unfortunately, frits and lithium carbonate are not available in my area. Can you suggest me a no-frit crystal glaze base recipe which I can test? Would appreciate if you could also suggest the firing cycle.

Hey Nasmul,
A good one to try is listed in Peter Ilsley’s book… I’ve found that most of the non-fritted varieties tend to become “overnucleated”.

By: Coral Bennett

Coral Bennett — Thu, 26 Mar 2009 14:32:41 +0000

I am facinated with crystaline glazes but as an inexperienced potter I have been really nervous to start experimenting. Having read your article I’m inspired to try. Thank you for a wonderful article and site, I am constantly amazed at the generousity of ceramicists to freely share their information and knowledge

By: Jennie Keatts

Jennie Keatts — Mon, 25 Aug 2008 01:50:01 +0000

This is a lovely site and your work is beautiful. I was interested in looking at crystalline after a (rather offensive) member of our community in NC proclaimed he was one of the best in the world. Your work and your information is so nice, so far beyond what I have seen. I have friends, Bulldog Pottery, that do some interesting crystalline work, very unusual to my untrained mind. I make jewelry with pottery stones using Jugtown Pottery glazes and have been interested in trying crystalline on them. Thank you for such a nice site.

By: Jesse Hull

Jesse Hull — Sat, 08 Mar 2008 18:28:34 +0000

Adding flux (frit) and stabilizers (alumina) can produce a back & forth / tug of war effect up to a point. The reason to add alumina in many types of glaze is to create a wider window to work within at the top of your firing. This is not always the case, however –especially concerning a glaze that is melting well below the targeted peak.

My guess is that the increase in alumina will simply encourage nucleation (resulting in more crystals than you may want to have in terms of the aesthetic), long before it impedes running enough to matter. Therefore, a focus on the specific gravity constant of your hydrated glaze(s), the peak temp (including any hold there), and application position/ thickness would seem more valuable to me. All of these things translate into how much glaze and where it is on your pot. Additions of what may become “refractory seeds”, which you’ll have to try to dissolve at a temperature when the glaze will be flowing rapidly (the variable you’re trying to minimize), may just put you into another realm of hurdles.

Having said this, John Tilton uses additions of clay (silica/alumina) to his glaze, adding benefits to application as well as the opacity and color effects he gets (marvelous stuff!). I believe John told me that he could add 3-4% EPK to a glaze w/o too much change visually. John goes for smaller crystals, so his pots don’t get as crowded as mine would if I had to deal with the same number. But, Derek Clarkson also incorporated 1-2% alumina hydrate into his glazes to balance a formula to his liking, and he achieved huge crystals on wide open ground. -So I certainly don’t discourage testing…

Using your glaze base, I’d just mix & fire a simple line blend, incorporating additions of alumina hydrate or grolleg kaolin at 1.5 - 3 - 4.5 - 6% for referencing where to proceed. Remember to pay attention to the variables above (specific gravity, thickness, etc), or you may not be able to reproduce any goodness that you find.

By: Phil Hamling

Phil Hamling — Sat, 08 Mar 2008 18:26:38 +0000

Jesse,

I want to begin testing glazes with increased viscosity to help minimize their flow off the work and have been considering the addition of alumina as a starting point. How do you feel about this approach? Can you suggest an addition range? Will the addition of alumina increase the refractoriness of the glaze to the point where I will need to add additional frit?

Phil Hamling

By: Jesse Hull

Jesse Hull — Fri, 07 Mar 2008 03:51:42 +0000

Thanks Salman… and I found your own work to be quite nice.
I particularly like Pot ID : 1379.

Have fun!

~jesse.

By: Salman

Salman — Fri, 07 Mar 2008 03:46:28 +0000

Hi,
Its lovely 2 visit Ur site as a matter of fact since I m a studio potter as well & making crystalline pottery but I found Ur work inspirational.