I recently purchased a jar of Golden (a popular, well-respected brand) Coarse Pumice Gel Medium for use with a painting commission for artwork to be hung in a school. I don't see many reviews of the product on the internet, so I thought I'd write a short one.
My project involves depicting the façade of a stone building on panel, and I was looking for something to mimic the rough stone texture. I was happy to find Golden Coarse Pumice Gel at the art store. There is also a Fine Pumice Gel and an Extra Coarse Pumice Gel, but this middle one looked like it would do the trick.
It's pretty gritty stuff, much like sand in a gel that's about the same consistency as toothpaste or dough for a cookie press. I was worried that the coarseness would come at the expense of durability, which would be a problem if the artwork is hung in a high-traffic school lobby.
In fact, the medium does seem pretty durable and adheres well. I learned that "over brushing" tends to spread out the medium too thin, so that there isn't a good acrylic-gel-to-pumice ratio, making it crumble off; however, if applied just a little thicker (and it can still be pretty thin), at seems to stick and harden quite well.
The medium is a neutral gray that looks more opaque while still wet; as it dries, the acrylic element turns transparent, just as with most gel mediums. The pumice grit, of course, stays gray.
The gesso-primed panel I'm working on is pretty smooth, so getting an even application took a little figuring out, but I learned that getting the Coarse Pumice Gel on the brush, then dipping the tip of it in water, gave it just the right consistency to spread it on the way I want it.
After it dried, I applied a layer of Golden Semi-Gloss Regular Gel, a fairly heavy bodied medium, for a few reasons: 1) To increase the durability, because I imagine that, if it's within reach, school kids (and probably many adults) will be running their fingers over it to feel the texture; 2) To sort of level off the coarseness a little, so that it doesn't soak up as much paint when I start applying color; and 3) To smooth out areas where the grit was just a little too gritty and coarse for the stonework being depicted.
I have never before done a piece like this (very textured with sculpted relief elements), so it has required quite a bit of planning ahead and testing. I created a small "proof of concept" in the way described above, and I was very happy with the result. The Golden Coarse Pumice Gel Medium gets four stars out of four from me for the assistance it has given me in getting the effects I want.