(Note: This article, and other hobby tips articles, are posted on my website at
www.weetoysoldiers.com) I first came across gesso a few months ago on TheMiniaturesPage.com discussion forum. At once I was intrigued: Here was something that could be brushed on, was non-toxic, water-thinnable and water-washup, and works wonders as a primer? I must investigate!
I had primarily used spray-can varieties of primers, anything from hobby-specific like the Tamiya Gray Surface Primer, to the hardware store-variety like OSH or Krylon or Rustoleum Painter's Touch. They all work well more or less, but, in my opinion, have a few major drawbacks. One, the weather and lighting condition has to be right -- too much humidity or too windy or too late at night, and you're out of luck. Second, and more importantly, the solvent- and lacquer-based primers have nasty, sometimes carcinogenic, toxic chemicals that I'd rather do without. Third, unless you're really careful, it's easy to overapply the primer and end up with buried/obscured details.
Gesso is a thick-ish liquid surface preparatory compound used to prepare artist's canvass before painting. It contains finely ground chalk with some sort of glue or binding agent. Different brands of gesso are made differently -- apparently some carry carcinogenic warnings, and some are certified non-toxic. I've also read that it's made of plaster of Paris with glue. Either way, it provides an excellent adhesive "tooth" for paint to grab onto. I've been priming miniatures with gesso for the past six months, and have been very pleased with results.
Now, the obvious down side is that it is brush-applied, and thus, somewhat time-consuming. This may not matter if you are a sloooooow painter like me, for whom the measure of progress and achievement is not the number of finished miniatures, but rather a happily cluttered workdesk full of miniatures in progress. I've heard of people asking about airbrushing gesso, but I honestly wouldn't recommend it -- the mix is thick enough to guarantee blocking and messing up your airbrush. And if you thin it to the point of being able to somewhat successfully airbrush it with an external-mix airbrush, then I would venture to guess that it would lack the cohesion to act properly as a primer.
The local craft stores carry Liquitex brand (the only brand I've used) of acrylic gesso in white, black, and clear. You can tint the white and clear gesso with inks or paints of your choice (well, you can lighten black gesso as well, I suppose, but most people will find it easier to go from white to darker than black to lighter). I started out with white gesso and tinted it with black craft acrylic paint, to give a nice, neutral grey look. I thin it with Tamiya airbrush thinner, but you can also use distilled water. Liquitex website states that you can use up to 1:4 ratio (25%) of water to gesso to thin, and to use water and the Liquitex Matte Medium in equal amounts if thinning more than 25%. I've thinned it way more than 25% using the Tamiya Airbrush Thinner, but I've found that thinner gesso tends to get scratched off easily in handling.
I eventually got a bottle of black gesso as well, as I found myself applying a coat of black ink wash to grey gesso-primed miniatures when I absolutely needed a black basecoat.
Here are my supplies for making primer mix -- Gesso, Delta Ceramcoat craft acrylic black paint (99 cents at the local craft store), Tamiya airbrush thinner in a dispenser bottle, and of course, a mixing pot:
The following image shows the progression of mixing gesso: first you start out with a dollop of gesso (the quantity obviously depending on how many miniatures you are going to prime!), then add black paint, then add thinner or water and mix thoroughly, and finally, you have a nice, shiny, smooth solution of primer, ready to use.
Here are two pictures of the Lord of the Rings plastic Warrior of Minas Tirith figure, before and after priming with gesso:
When applied, gesso goes on thick and obscures details, but as it dries, it shrinks down and goes on flat. In fact, it works so well that you can apply it directly to prepainted figures with no loss of detail (this would obviously depend on how thickly the paint was used in painting the figure):
Another nice thing about working with gesso is that you have absolute control over how it's applied. Put it on too thickly?
No problem! Just use the brush to wipe away the excess. Much easier, cleaner, and safer than trying to damage-control over-applied spray can primers.
... notice how gesso obscures details above when it's wet. It dries down to reveal the details:
Here is a comparison photo showing gesso-primed plastic gun (above), and before priming (below):
Here's a picture of a white-gesso-tinted-with-black primed metal miniature, from the Dark Age line of figures. The leftmost one is primed with gesso, then baremetal, then a figure primed with Tamiya spray can grey primer:
... and a closeup of the gesso-primed miniature:
When the leftover gesso dries, it peels off in one rubbery piece:
One note about gesso safety. Apparently, some brands of gesso come with carcinogenic warning labels. The Liquitex brand I use is certified non-toxic, including meeting the California Proposition 65 requirements. Here's the blurb from the MSDS (Material Safety Datasheet) for their gesso:
"Product has been certified as non-toxic by The Art and Creative Materials Institute, Inc. and conforms to ASTM D-4236 Standard Practice for Labeling Art Materials for Acute and Chronic Adverse Health Hazards."
There you have it. Obviously, if you have hundreds of figures to prime at once, or if you are working with smaller models (say 10mm and smaller) where any kind of primer might obscure details, it may not work for you. But if you are looking for a safer, use-at-any-time method of priming your miniatures, give gesso a shot!
