How to Smooth the Surface of your Clay Object – 3 Affordable Tips

Ceramics can be produced in several ways. You can press the clay in moulds, hand-build an object, or merge slabs.

Depending on completion or decoration it can be necessary to smooth the surface as best as possible. How to smooth the surface of your clay object?

If you intend to use slip on the finished form, it’s best not to smooth the surface too thoroughly. When the clay molecules are pressed too tight against each other slip or engobe will not attach very well.

On the other hand, if you plan to put your work in the smoke or raku kiln, it is better if the surface is smooth and polished. The smoother the better.

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How to smooth the surface of your clay object?

Handmade tools like shaped credit cards or wooden beads on a handle are perfect to smooth your ceramics. So are light bulbs.

Smoothing ceramics the right way

It is best for a novice ceramist to start with grogged clay.

Grog was called ‘pebble-stones’ by my students but is fired clay that is ground up and added to clay in varying percentages, depending on what kind of work you plan to make. 

The advantage of the grog is that the work does not break easily in the kiln. The downside is that the surface can look rough.

These are tips to get the clay surface you desire.

#1 Costs nothing, after all, we use plastic cards all the time

An expired bank card, an access card to the gym or a gift card I got from a perfumery: when I looked inside my wallet I had numerous cards I all got for free and were of no use anymore. 

They’re really handy to smooth the clay surface with. Since I had plenty of cards, I had cut several into kidney-shaped or round forms for specific projects.

And another tip – not for preening, but the opposite – I cut some cards with pinking shears that I used to roughen the edges of the clay. I needed those when I was building with slabs.

Related: How to Make Perfect Slabs of Clay for Hand Building Ceramics

#2 Costs a little, a tool I used a lot

I made a lot of my ceramics with the help of moulds. As you probably know, it’s important to avoid air pockets in the clay, so you have to press the clay into a mould very well.

If you push the clay into the mould with your fingers, you can feel if the thickness becomes the same everywhere. That is important but you can’t exert as much force as with this homemade tool.

With a big wooden bead on a handle, you can rub the clay into the mould, thus making both the inside and the outside clean and flat.

For lack of a better solution, I used thick iron wire as a handle until I got an old-fashioned washing brush from a friend. The stem fitted perfectly around the smaller one of the beads.

#3 A second life for failing light bulbs

At the beginning of my clay days, I used a spoon to polish the surface of my ceramics and hated the metal stains that emerged. They didn’t vanish when fired in the kiln, unfortunately.

Failing light bulbs were a perfect solution for this problem. Not only do they leave no marks, but I also found them easier to hold.

And because our craft is in reality such a ‘dirty’ profession, it is nice to know that we can give a second life to broken things this way.

I had several kinds, so there was always a lamp that fitted the surface.

Related: Start Making Ceramics Now with Clay Tools from the Kitchen Drawer

What not to do when smoothing clay

You may be tempted to run a damp sponge over the surface. I did so in the beginning, always surprised that when it dried, the surface was still rough. That didn’t help.

Sanding the leather-hard object with sandpaper was another method that didn’t work well. The grog will cause cavities. In addition, clay dust is very unhealthy, so sanding is not recommended from that point of view either.

You should try out for yourself when is the best time to apply one of the 3 methods I described above. Sometimes you can start when the work has not yet dried, sometimes it is better to wait until it is leather-hard.

Good luck!

Are these helpful tips for you? Please let me know in the comment box below.

This article is an update. Originally published on 9-05-2013.