Protecting glazes in an open studio

[Donna Kat]

I think one of the more expensive mishaps that can happen in an open studio is people ruining glazes by carelessness and/or not knowing what they are doing.  Since any member has access to an open studio during times when it is not monitored it is almost impossible to enforce reasonable behavior by all members and once you pass over a certain number of members you cannot even expect members to monitor one another.

I have no ideas on what to do in the case of having over 100 members in an open studio.  Anyone with thoughts/

[George Lewter]

With that many members, a studio technician should be in the glaze area much of the day, guiding and instructing, and issuing "citations" for repeated bad behavior. I've seen studios stock glazes for general use, and advanced members keeping their own signature glazes away from the madding crowd in private storage.

A glaze room should not be an unrestricted playground for novices, unlike a wheel or hand building area. Novices might be allowed access only when accompanied by a qualified mentor member or technician? Glaze room certification class?

[Norm Stuart]

The wonderful part of letting someone make a glaze is it's self-grading. Their test tile reveals whether they got a passing grade.

The only restriction we impose on inexperienced members making glazes is the quantity they can make. Of course we watch them to make sure that bags of materials don't get cross-contaminated. We also have one high silica pallet, with silica, talc, and bentonites, which officially requires a respirator to access but the risk is fairly low.

We purchase 200 mesh silica which is the cheapest grade with the largest 75 micron particle size. It's so large it's very slow to melt but also very difficult to aerosolize. In contrast A25 silica has a particle size of 7.5 microns and it's spooky stuff.  I've stirred a one pound bag lightly with my finger which created a little cloud which slowly poured over the edge of the bag down onto the table like fog. If I were making a Cone 018 enamel, A25 silica is what I'd buy - but it's not a very safe material.

As a result I never would have guessed we'd have so many people at our studio making glazes. It's been very successful after a very slow start.  There was a learning curve to having enough knowledgeable people at the studio without me needing to be there.  I still get the occasional phone calls from the studio, but that's terrific.

The one problem we're run into is using "bucket glazes" rather than pint or quart deli containers. People can use a paint brush to mix a pint or quart container thoroughly or shake it with the lid closed.

Unfortunately people are generally reluctant to reach down to the bottom of a glaze bucket with their bare hand to make sure there is no sediment on the bottom.  Since they're not used often they are rarely fully suspended, even after stirring with a whisk or toilet brush.

The result is people will apply glazes without most of the frit and heavy colorants which are sitting at the bottom. Using clear as an example, this ruins their ware with a milky unmelted "glaze" and also shifts the glaze chemistry for those who use it later. As a consequence buckets of glaze slowly "go bad" as the level goes lower as it's rarely fully mixed.  As a result buckets of glaze have become less popular, which is fine with me.

George Lewter said:

With that many members, a studio technician should be in the glaze area much of the day, guiding and instructing, and issuing "citations" for repeated bad behavior. I've seen studios stock glazes for general use, and advanced members keeping their own signature glazes away from the madding crowd in private storage.

A glaze room should not be an unrestricted playground for novices, unlike a wheel or hand building area. Novices might be allowed access only when accompanied by a qualified mentor member or technician? Glaze room certification class?

[Gina Skillings]

I think this is always a challenge in any open studio even with fewer members. We have only four classes per week with two instructors. Students have access to the studio 6 days a week which means there is rarely a teacher present. I think the idea of 'certified' members to be present is good but only works if the glaze area can be closed off when no one is present to monitor.

We have the same problem with bucket glazes, some people not fully mixing them. I suggest the electric mixer and sieving glazing that have not been used recently but that often simply changes someone mind as to which glaze they want to use. Sometimes we'll go through and thoroughly mix/sift all the glazes but then some won't be used for months so I think it's best to mix/sift as needed. 

Along the line of group studios I suggest records be kept of materials purchased. At our studio I'm told that some of the popular glazes no longer 'work' as they used to and I think part of the reason is that the recipes are old, materials have changed but no changes were made to the recipe. No one knows when the current supplies were purchased so we don't know which ingredients need adjusting. Record keeping with chemicals and the kiln is one of my goals for our studio but introducing new ideas is tough. (sorry, this last bit doesn't directly relate to the original question, but is something I'd want anyone working with glazes to be aware of, to check for different versions of the same chemicals)

[Norm Stuart]

We've had variability problems with only a limited number of raw materials.

Cornwall Stone we make our own using the recipe on Digitalfire, also available in the Insight-Live database.

Lithium Carbonate which is too coarse is the sort most available from non-ceramic suppliers, such as eBay, and doesn't work well.  I much prefer using lithium fluoride which provides more flux and a nicer look.

Red Iron Oxide, we buy only man-made pure red iron oxide to avoid red turning out brown, but we also use Prominfer Spanish Red Iron Oxide which is amazingly consistent.

Rutile, being a natural ore, causes glaze changes each time we buy a new milled reflux 5 pound bag. We have better luck with uncalcined rutile. The calcined products we've tried create a look which is little different from using refined titanium dioxide.

Talc (Pioneer) is dark grey from organic material which can sometimes cause problems, so we usually calcine this material at 900 F or higher with a long hold. I have a large ceramic bowl with a crack in the base which permits air-flow through the material.

Wood Ash is of course very variable but we rarely use it.

I've not seen any consistency problems with any other raw material or man-made material.

But I've seen a lot of:

inconsistency in weighing ingredients;

choosing the raw material from the wrong bag;

leaving ingredients off the list, which can be checked by the finished weight of the recipe;

all of which are the usual cause of a glaze which doesn't turn out correctly.

[denise a mendez]

One of my staffer's  monitors the glazes on a "daily" basis and has a little specific gravity stick to make sure the water content is okay.  A couple of things:

-try to have bullet proof glazes anything that is too runny, we don't stock as its too dangerous for our kiln shelves

-monitor and mix the glazes a few times of week.

-limit the number of glazes you have  We have about 18 which I still think its too many

-leave signs everywhere, but between you and me I really don't think most of the people in my studio can read ;).... 

I don't let people mix their own glazes unless they have copious amounts of experience an knowledge.  Some chemicals get pretty pricey to throw away!

[Donna Kat]

This is a terribly old post but if it gets revisited I would like to add my 2cents.

I think this was one of the most frustrating aspects of being the AR in a studio of over 100 people. The first thing I did was to take off all the name labels from the lids of the buckets and to replace with the label "DO NOT ADD OR REMOVE WATER" STIR WELL". When you have the name of the glaze on the top of the lids it is more likely that someone will put the wrong lid on the wrong pot and then people can more easily pore back the wrong glaze into the wrong bucket. I never put a ID label on a lid. I then went to every deli, bakery, grocery store and begged for their 5 gallon buckets. I was able to get green, white, blue and black buckets that color matched the glaze. I printed out very large labels, shipping taped both sides of the paper and then taped two of these labels to each bucket so no matter how the bucket got turned you could see the name. I weighed the glazes (or the student workers did once I trained them) and used this metric for adding water. Anyone caught messing with the glaze would have been scolded severely. They did not do so. We had fewer problems with our glazes after this. 

We had a glaze board that hung on the wall. This was there for as long as I can remember and was a great idea (wish I knew who started it). It was a 12X12 design (all our major glazes). So 12 rows and 12 columns with glaze 1-12 across and glaze 1-12 down. The tile would be glazed all the way down with the glaze on the column and then half way down with the glaze on the row. That let you see what each glaze looked like over and under each glaze including itself. The tiles had a hole in the top and could be taken down to look at or replaced if the glaze changed when wanted. There were actually 2 tiles for each glaze. One in white clay and the other in one of the brown clays. The labels were easy to read.