A question I get asked a lot is how long does it take to make a mug and my response is usually to ask if they mean active time or from start to finished mug. Active time for a single mug might be 15min, but from start to finish is closer to 3-4 weeks. So I thought I'd take a moment to explain what goes into making a mug, vase, or any other piece of my pottery. I'll start after I have the clay and glaze on hand, but just to let you know, due to where I live, I drive 3 hours round trip to pick up my clay. Shipping clay is expensive and the one delivery truck I've tried to connect with has been far to infrequent to make it beneficial. So I put on some music and enjoy the drive.
It starts with taking a chunk of clay and flattening it into a 20" long rectangle about 3/4" thick with an oversized rolling pin. I then take this thick slab, place it on a piece of canvas, cover it with another piece and carry it out to the garage where my slab roller is. Cranked through the roller in one direction, then flipped over and rolled in the other direction, I now have a thin slab between the layers of canvas which I carry back to the studio. I remove one layer of canvas and use a drywall mud tool to smooth out the surface. This removes the canvas marks and also helps compress the clay to help control cracking and warping. Using the canvas the slab is on, I flip the slab and repeat on the other side.
Now that the slab is prepared, I dust it with cornstarch so the texture I want to emboss does not stick. Once the texture is stamped, I use a yard stick to measure out and cut the pieces into the clay. This is the pattern making part of the process--handles, bodies, and bottoms are all accounted for...and once all the lines are drawn and cut, I can see how many mugs or vases I'll get out of this particular piece of clay.
The handles are made first by rolling the clay into cylinders. I make more than I need, not because they break, but because it's the most time consuming part and if I make more handles, they are ready for the next batch. Once I know how many handles I need for this set, I bend them over a tube then press them onto a piece of board as if I'm pushing the handle onto the mug. I'll set the board of handles aside and let them set up while I move onto the next step.
I take each mug body piece and wrap one end onto the other. The seam is smoothed out on the inside with a rubber rib while the overlap on the outside is left. The rim is then scored with yet another tool and clay slip applied before a piece of slab is added for the bottom. These steps are then repeated for each mug body until the slab is used up. Oh, I also make sure I stamp my name into the bottom before it is attached. Once all the bodies are formed, the handles have had enough time to stiffen up. The handles and mug bodies are both scored and slip applied before pushing the handles onto the mug. While the mug looks done, it is set aside again to dry a bit more.
Once the mug has dried to what's called the "leather hard" state, I trim the bottom edge and lip and use a finishing sponge to smooth out the edges...now the mug form is done and ready to dry completely. It can take a few days to a couple weeks for a mug to become bone dry. It depends on the room humidity. Since my studio is not air-tight from the outside, the humidity fluctuates and I will often bring drying work into my basement which has a dehumidifier. It's still important to keep the work covered in plastic to prevent it from drying too quickly. If one piece of the mug dries too fast, the clay can crack. Unfired clay can be rehydrated and reused, but it's still frustrating if it happens to more than one piece.
The brittle bone dry clay is extremely fragile. I look it over to make sure there are no sharp dried clay bits. If found, I sand the rough bits down. Clay dust is dangerous so sanding is best NOT done, but if it must, I wear a mask and exhaust fan ventilation. The mug is then loaded into the kiln for a bisque firing. I fire to Cone 05 which is about 1888 degrees. This sets the clay while still being porous. A bisque firing takes about 10 hours (in my kiln) to reach temp and then at least another 10 hours to cool back down. Once removed from the kiln, the mug is sponged off to remove any kiln dust that accumulated and set aside to dry before glazing.
I stain the outside of my mugs first, removing excess stain with a sponge, and then set aside again to dry before glazing the inside. It's important to let the mugs dry between each step since glaze is primarily water...the bisque needs to be able to absorb the water in order for the glaze to stick. If the bisque isn't dry, it can't absorb water and the glaze will most likely fail. When applying glaze, I prefer to brush or pour the glaze inside. It depends on my mood which method I use. If I have a lot of work to glaze, I'll pour...it's quicker.
Once everything is glazed, back in the kiln it goes, this time fired to Cone 5, about 2189 degrees. Glaze firings are a bit quicker, about 6 hours for me but just as long to cool as a bisque if not longer. I find it's also more important with a glaze firing to keep the kiln closed until the temp is closer to 100 degrees to avoid any thermal shock from cooler air entering the hot kiln. That's why you might hear many people say opening a kiln is like a child waiting to open presents at Christmas...the anticipation can be intense and best not rushed.
After the pieces are cool enough to handle, I fill each one with water to make sure it doesn't leak...and if it passes the test, I take a diamond sander sponge to quickly smooth the bottoms and handle before washing the piece and calling it done. I now have a finished ready-to-use mug.
If you've stuck around through this longer than usual post for me, you now know what goes into making one of my mugs and what my process looks like. Each potter has their own methods, tips, and tweaks they use along the way. I've never felt there was a right or wrong way to make ceramics....do what works for you. This just happens to be my process for making a mug.