How to Safely Sand Pottery
This kiln fire produced eighteen beautifully bisqued pieces that are ready to sand. Before I glaze my work, I make sure to sand each piece to create a smooth touch that will not scratch wood or other surfaces.
Sanding improves craftsmanship and adds value to your ceramics. It also improves the tactile connection a person has with your work. Clay with a high grog content has a visual and textural intrigue as it develops after firing. Grog also feels rough—it has a tooth that scrapes and snags. I’ve found that sanding groggy clay produces a velvet-like smoothness as the grog is now level to the clay and still substantial in texture. Sanding clay with little to no grog creates a smooth coolness that’s similar to soapstone.
As a maker, I’ve become more aware of the connection people make with art, and refining your work can mean the difference of a sale. When you’re at a market, do you find yourself picking up pottery, observing its surface and design, and feeling the bottom to ensure that it won’t scratch your table? If the clay feels unintentionally rough, you might put it back on the shelf.
If you are a new potter and wondering how to prevent this scenario let’s work together to remedy that. I find pottery students turn to sandpaper as it’s the logical solution— sandpaper is meant to sand—but bisqued pieces are harder than the paper itself. If you’ve found yourself vigorously scrapping the surface of your pottery with little results, know that you’re actually wearing down the paper, and not your ceramic work.
The solution is to buy drywalls screens at a home improvement store. Drywall screens are available in different textures at $5 a pack. You’ll want to pick up a medium and fine grit, and cut the screens into 3-inch squares, or a size that is manageable for you. Start will a medium grit to remove larger pieces of grog, and use the fine grit to finish the surface. Fine grit drywall screens are recommended for sanding porcelain and low-grog clays.
Now, I have to tell you that you absolutely must sand your pieces wet. Absolutely, without an exception. Silica is a real threat to a ceramist’s health, and exposure to it can lead to lung cancer. If you do a simple search, you’ll find that silica dust remains suspended in the air for hours, and can not only affect your health, but compromise your classmates’.
This is an alarming truth that must be shared with new ceramics students and potters as you can do your part to reduce silica exposure. The safest technique is to wet-sand bisqued fire clay by soaking each piece before sanding with a drywall screen.
Wet sanding bisqueware is a safer alternative as wet silica is too dense to float in air. Because your work has been fired, you don’t have to worry about it cracking when exposed to water. A bisqued piece of pottery can handle being submerged in water without being damaged.
I dunk my bisqued pieces in a water bucket, and will continue to wet the drywall screen and pottery as I sand. You’ll find the screen will wear down after sanding a few pieces, but you’ll also see a good amount of grog coming off of your work. One screen can sand several pieces of pottery.
If you clay has a lot of grog, you can choose to submerge your bisqueware in water to saturate it as you sand. Be prepared to hear your ceramic pieces “squee”. It’s a funny sound that occurs as the fired clay rapidly absorbs water. Bisqued clay is highly-absorbent and the high-pitched sound is an example of unvitrified clay.
Vitrification transforms clay from a porous body to a surface bonded to its glass particles at a kiln fire appropriate to the clay's cone. Vitrified clay is water impermeable, making glazed and specified unglazed surfaces functional and water resistant. In terms of food-safety, you want your pottery to be vitrified so the clay does not absorb liquids and harbor bacteria.
Bisqued clay is extremely absorbent, which allows the glaze to seep into its porous surface. After your wet-sand your pottery, your piece will be waterlogged and you’ll want to let the bisqueware dry under a heat lamp or sit out for a few hours, depending on the heat and humidity of your work environment. Once your work is completely dry, it will be ready to absorb glaze.
It took a couple of hours to sand and dry eighteen pieces, so allow yourself time. Now that my work has been safely sanded, it will be glazed and fired for a second time in the kiln. 🔥