Mount St. Helens Glazing

my mixed ash/low fire glaze ready to fire

Early this winter I was invited to make some work for a Mount St. Helens art show. The show date and location have been shifted to account for the pandemic. I was given a new deadline of last Wednesday which I have now missed. I don't very often miss deadlines like this. I think that with the spring quarter moving online, the general worries about the pandemic, and the specific anxiety of trying to work from home while my daughter is also home all day, I had reached a point of just not being able to make everything work.

bisque with two volcanos and some sprigs, ready to unload

I did get the work made and bisque fired by last week's deadline, but pure white wasn't really the look I was going for. I still have some serious uncertainty about the end results, but I glazed this weekend and I'm just about ready to fire the pieces. 

Mount St. Helens eruption box ready to fire

The reason I am uncertain is that I made a significant mistake when I began this project. I was anticipating being able to use some Mount St. Helens ash glaze made by some fellow artists, and though I knew this was cone 6 glaze, I started building with cone 06 clay. 

cinnamon underglaze on interiors and some box exteriors

I had the low fire clay out to make a batch of sprigs and I simply didn't think before starting to build. I'm going to chalk it up to trying to squeeze in too much thought into my week. Usually I work on projects in the summer when I'm not teaching. Occasionally I work on projects during breaks or on the weekend during the year. I can honestly say that I've never worked on ceramic projects during a pandemic while trying to adjust to a fully online quarter and preparing for contract bargaining as president of our faculty union while my daughter is also home with me all day, every day. My brain was (is) full. I couldn't cope.

my three glaze tests at cone 06

Since the work was made in low fire clay, I can't fire it to the higher cone 6 temperature without risking damage to the form. I also couldn't remake before the deadline, so I figured I should try some glaze experiments during my bisque firing. I had the cone 6 glaze, which I guessed was highly unlikely to melt at cone 06, but I figured I should test it anyway. I also tested a glaze that mixed one part of the cone 6 ash glaze with one part of a cone 06 gloss glaze. The third glaze I tested was equal parts ash and 06 glazes with some added red iron oxide. I used the sophisticated technique I learned in graduate school from my checked-out ceramics professor: scooping a random amount so that the results can never be replicated (see above re: no more brain space).

glazing and under glazing in progress

The results weren't particularly surprising. The Mount St. Helens ash glaze on its own didn't melt at all at cone 06. Cone 6 is roughly 2165 - 2232 degrees Fahrenheit, while cone 06 is only 1798 - 1828 (Cones melt based on time and temperature, so the range refers to a slower or faster firing), so the difference is significant. The mixed glazes also didn't melt correctly--again, not surprising. But the mixed glaze fluxed a bit, meaning the surface is starting to become glossy, and has a thick, semi-opaque texture. This texture reminds me a bit of lava, which seems fitting for this project.

peeling off the resist

Because I really want to use Mount St. Helens ash (pumice) in the finishing of these pieces, I'm happy to see what happens with minimal testing. If I were going to fire these pieces, as originally planned, to cone 6, I have a variety of colored glazes that I was planning to use. For cone 06, I have clear glaze in matte or gloss. So, I have used some of my underglazes to try to add some interest to the forms. 

glazing in progress

Did I take pictures of my work after I had finished adding the underglaze? Of course not. Thinking and planning are apparently not things I do anymore. Nor, according to the images shared here, do I take care to check that my images are in-focus, so this is what I've got. Done is better than perfect (I mean, assuming perfect isn't done, right?)

applying the Duncan Mask & Peel to the lid 

I used cinnamon underglaze for the interiors of all the pieces, as well as for a wash on the textured surface of the eruption and venting. I usually like to layer two colors of underglaze over each other, but I simply didn't leave myself enough time for this project, so this will have to do. 

I put a clear glaze over the underglaze on the interior of each piece, so the color looks pink (or white) before firing

Usually when I layer underglazes, I fire them in between, which means I can wipe the surface after adding the glaze. Since I didn't have that middle step, I used some resist which protects the underglaze from accidental drips of glaze and then can be peeled off before firing, taking the over glazed mistakes with it.

this box has both types of glaze on the outside. We'll see how it looks when I unload it.

I used underglazes alone in in combination for all of the pieces, but also left the bare clay color visible in several. I am concerned about how this will work, but time is passing and these are past due. I used a gloss glaze over the cinnamon underglaze inside every piece, then used a combination of my low fire glaze and the mixed ash/low fire glaze for the exteriors, leaving one without any exterior glaze for contrast. The underglazes I use are velvets, so they tend to look nice without a glaze anyway.