Sgraffito is without a doubt one of my favourite techniques in the whole of pottery. You can see it in the majority of my current ceramic work. It's such a satisfying, therapeutic process and the effects boundless. I haven't explored even close to all that can be achieved with Sgraffito but here are my tips to get you started.
What is Sgraffito?
Sgraffito, meaning 'scratched away' in Italian, is the decorating technique where a contrasting colour is applied over the top of a leather hard, unfired pot and then etched into to reveal the colour of the clay beneath. Often times the coloured layer is slip, which is liquid clay, but I use Amaco Velvet Underglaze. This isn't an ad- it's just the brand I first tried and I've loved it so haven't needed to try others.
Underglaze vs Slip
Slip is more cost effective and can be made yourself. You can add stains to achieve the colours you want too. However I use underglaze and the reason for this is that I find coloured slip only becomes a rich vibrant colour when it's been fired twice and is under a layer of clear glaze. With the Underglaze, straight out of the jar it's pretty close to the colour it will be when fired. This means that I don't have to wait until it's fired to see the effect, and I don't have to layer a clear glaze over the top to get the rich colours I want. Often my sgraffito work is left unglazed so this suits me.
When and how to apply underglaze.
I use a brush to apply it, often on the wheel for speed. The more you layer, the deeper the colour gets so you have to be fairly even in application. I apply at least two coats on leather hard clay.
When to do Sgraffito on a pot
I aim to work on leather hard pots. If I leave the pot to dry completely it becomes too fragile to handle and etching into it becomes more difficult. This is especially so if your clay is at all gritty, as it will cause underglaze to flake off, making lines look jagged. It also produces dust which you want to avoid!
What if the pot drys too much?
If you are anything like me, timing when a pot is just right when you have other life stuff to keep you busy can be tricky. I tend to dry my pots super slow in a plastic container so I get a much longer window. However if they do go a bit beyond I spray them with a little water and put them in my damp box, (plastic container with a couple of inches of set ceramic plaster in the bottom) add a little water to the plaster and leave them overnight or longer until they have softened just enough to sgraffito into.
What sgraffito tools to use?
I use a verity of tools and really you can use whatever you have to make marks into the surface. Have fun and try out the tools you have! There are all sorts of techniques to mark make into the surface including chattering (very cool), carving, line work, text and so on.
A lot of my work is line work, so I use an 'embossing and stylus tool' found here on Amazon. These tools were a tip gleaned from the VERY talented Simon Olley of Olley Pottery. Check out his amazing work! The tools are super cheap to buy and I've had the same set from the start. I also occasionally use dentistry tools, as these are commonly used by sculptors so I had these from my uni days sculpting. These again can be super cheap to pick up and last forever.
I also use the various clay trimming tools I have too, to make deeper and wider marks.
I have yet to buy and try an expensive sgraffito tool, but if you have a recommendation that will rock my world then please do tell me!
The final tool I use is a soft wide brush (I actually use a makeup 'fan' brush) to brush away shavings as you work.
Health and Safety tip
I suggest wearing a mask, especially if the clay is at all dry. Spray the shavings with water before clearing them up as they will dry as you work, creating dust. Clear up straight after any sgraffito session to avoid dry clay.
I always check that there aren't any thin areas of underglaze, or unwanted marks and touch it up by adding a little extra to the area. If I make a mistake I can often gently scrape it back to a smooth surface, add underglaze and start again on that shape.
I fire to cone 04 for bisque then cone 6 for my stoneware clay. I have found if the firing runs too hot the underglaze can bubble a little in the heat. So for this reason I try and make sure that any part of the pot that may be vulnerable isn't too close to the elements. For example, I'll turn the handles of the pots in towards the centre away from the elements. One way to solve this is just to check your kiln isn't getting carried away and not to over fire of course....:)
I have found some of my home mixed glazes can make the underglaze run or bleed a little. So test your clear glaze before applying a layer over your work. If you buy off the shelf commercial glazes, have a look at getting a clear glaze in the same brand as your underglaze where the manufacturer states it is suitable for going over underglaze. Amaco's Satin clear works very well over underglaze, but I don't love the satin affect.
Some of my mixed glazes change colour over the underglaze. Obviously if translucent then it will show underneath, but I have a lovely raspberry glaze that is opaque yet turns purple over Amaco's velvet black underglaze. I rather like it and aim for an overlap. However my cobalt glaze looks black as it's more translucent and runs like billy oh over the top of underglaze- I'm not sure why!
Makers like Joe Thompson at Old Forge Creations uses lots of various nifty guides to enable accurate shapes. I have the idea to try out his tip of using a laser level. With this, I could get some more accurate symmetrical shapes. However for now I really love the hand drawn look of my work in contrast to shiny sleek glazes. Plus I reckon I'd lose the enjoyment of getting lost in creating a pattern if I were to get too perfect about it.
If this post raises any thoughts, ideas or questions you would like to share please do contact me, I'd love to hear from you. If you want to see more of my work head to Instragram
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I'd love to see if you try this technique! If you do, share it on Instagram and tag me in your post!