Make Your Own Paint Muller and Slab

Of all the natural color-making ingredients I use, I feel the deepest contentment when I’m collecting rocks. Earth pigments have such strong characters. Even more than symbolizing a place, they ARE the place. Literally. I would like to think this is why I’ve been collecting rocks since childhood, but I bet it has more to do with a general love of nature and collections.

After collecting the earth, learning about it, and processing the material into a pigment, I usually make a watercolor paint. Natural watercolor paints can be made with minimal ingredients, allowing the pigment’s personality to come through.  

earth pigment ready for mulling

When I was first researching how to make watercolors from my collected earth pigments, I saw that most handmade techniques use a glass slab and muller. At the time, these tools seemed a bit pricey for something I was just beginning to explore. So, I came up with the following DIY version for a considerably lower price than a new paint muller and slab. 



  1. Find a slab of quarter-inch (or thicker) glass. I got mine from a local residential glass company, and I bet you could find one at a used building supply store, too. Be sure to have the edges blunted to avoid nasty cuts. Mine is one square foot, but you could go a little smaller or much bigger, depending on how much watercolor paint you want to make at once. 
  2. Buy/obtain an old glass electric insulator. I frequently see them around vintage/second hand shops. Select one that you can comfortably hold in your hand- so probably not the really wide kind. You also don’t want any chips in the rounded top. 

  3. Using glass etching cream, “frost” one side of the glass slab and the rounded end of your glass insulator. Follow the directions on the bottle closely. Do this last step in a well-ventilated area and wear protective gloves!  

DIY glass paint muller

And that’s how to make your own glass muller and slab! I had planned to “upgrade” to a traditional muller later, but my homemade version is working great. There are tons of videos and tutorials online showing how to actually mix watercolor paint, using both natural and commercial pigments. Other tools you’ll likely need are a palette knife, rag and containers for your paints.