What Glazing and Firing Does, and Why I Hand It Off
Okay. Your mug is dry now, or getting there. Handle's on, it's not falling off (probably), and you're looking at this thing thinking it's basically done.
It's not. Not even close. There's a whole part of this process I don't do myself, and I want to be straight with you about that before we get to the studio's kiln day, because I'm not going to pretend I know more than I do.
What actually happens between now and a mug you drink coffee out of
Right now your mug is what's called greenware. It's dry clay, and dry clay is basically dust that's agreed to hold a shape for the moment. It hasn't been anywhere near heat yet. If you dropped it, it'd probably just break into pieces, no drama. If you tried to drink out of it as-is, it would eventually turn back into mud in your hands, because it's never been fired. Water wins.
Here's the sequence from here:
First firing (bisque). The studio loads your mug into the kiln with a bunch of other people's pieces and fires it to somewhere around 1800-1900 degrees Fahrenheit. This is the firing that turns your clay from "dry dust held together by hope" into an actual ceramic material. After this it's called bisqueware. It's hard, it won't dissolve in water anymore, but it's still a little porous, kind of like a hard sponge. You could tap it and it'd make a dull clink instead of a thud.
Glazing. Once it's bisque-fired, you paint or dip glaze onto it. Glaze is basically powdered glass suspended in water with some other minerals mixed in, depending on the color and finish you want. It looks chalky and kind of ugly going on, nothing like the color it'll end up. That's normal. Don't panic looking at a bisque mug covered in what looks like gray-blue paste. It's supposed to look wrong right now.
Second firing (glaze firing). Back in the kiln, hotter this time, up around 2200 degrees Fahrenheit depending on the glaze. This is where the glaze actually melts into glass and fuses to the surface. This is also where all the chemistry happens that I genuinely don't fully understand. Why a glaze goes matte instead of glossy, why some colors shift depending on how thick you put them on, why the same glaze looks different on two different mugs that came out of the same kiln load. There are people who've spent years learning that and I haven't. I throw, I trim, I hand it off.
Why I hand it off
This is the honest part. I know how to center clay and pull a wall and carve a foot ring. Glaze chemistry and kiln temperature curves are a different skill entirely, and it's not one I've put the hours into. The studio has a kiln person who does. I'm not going to stand up here and act like I understand cone ratings and atmosphere and reduction firing just because I can throw a decent mug. That's a different craft that happens to share a building with mine.
So on glaze day, you'll work with whoever runs the kiln here. They'll show you the glaze options, tell you which ones play nice together and which ones you shouldn't layer, and they'll load and fire the kiln. That part's out of my hands, literally.
What you can control
You can control coverage. Even, not too thick, not too thin, wipe the bottom clean so it doesn't fuse your mug to the kiln shelf, which is a real thing that happens and is a bad time for everybody. Beyond that, a lot of what a glaze does when it hits temperature is out of your hands too. Two mugs dipped in the same glaze, same thickness, can come out slightly different. That's just true. It's not you doing something wrong.
I had someone in an earlier class who kept apologizing while she glazed her first mug. "Sorry, I don't know if I'm doing this right, sorry, this probably looks bad." I told her flat out, everybody's bad at this part the first time, that's the whole point of a first time. She relaxed after that. I wasn't saying it to make her feel better exactly. It's just true, and it seemed like she needed to hear it plainly instead of gently.
My opinion, for what it's worth: finish the piece. Glazing is the part where a lot of beginners lose interest because it's less physical, more waiting around for a kiln to do its thing on its own schedule. But this is the difference between a mug that sits half-finished on a shelf and a mug you actually drink out of. Push through the boring part. It's short.
Before next time
Make sure your mug is bone dry, no cool spots when you hold it against your cheek, before it goes anywhere near a kiln. A pot with even a little moisture trapped inside can crack or explode in the firing, and that's not a design flaw, that's just water turning to steam with nowhere to go. Give it the time it needs.