The best time to paint figures is when it’s over 50 degrees, because the first step is spraying them with a coat of primer, which requires a temperature of above 50 degrees. The problem is that when it’s that warm, that’s when you’re busy keeping up the yard and other stuff. Wouldn’t it be nice if you could prime your figures with something safe to use indoors?
It turns out you can. I’ve searched years for a brushable, non-toxic primer (preferably acrylic and water-based). Such a thing exists; I was just calling it the wrong thing. What you need is called gesso. You can order it online from Amazon or you can buy it in craft stores like Michael’s, Jo-Ann, and Hobby Lobby and use a coupon. If all they have is white, mix some black acrylic paint in with it (which you can get there as well) to darken it. Or mix in any other color you wish.
Because it’s acrylic and water-based, it won’t stick to figures unless you degrease them beforehand. Wash them down with a good degreaser like Simple Green and let them dry, then brush on some gesso or dip them, let them dry for a while indoors, then the figures are ready to paint.
I like to apply a couple of thin coats with a brush. You really need the second coat to get good coverage. Applying two thin coats in succession is a good way to avoid covering up detail. Two thin coats also dry faster–I find I can put two coats on within an hour of each other, and another hour is about all it takes for it to be ready to start painting.
When it’s dry, it behaves much like any other primer would. It’s dead flat and has some tooth in it, so your subsequent coats have something to grip onto.
Gesso costs a bit more than hardware store aerosol primers do, but you’ll waste less of it. I tend to run out of propellant in the can even though there’s still primer left in it. The convenience of being able to use it indoors and reduce waste makes it worth it to me. As a bonus, its compatibility with acrylic paint for tinting–which is great for speedpainting–also makes it go further, reducing the cost.
If you use self-tinted gesso to accelerate speedpainting, apply clearcoat to any part you don’t paint with a topcoat. It needs the protective coating in order to last. A cheap but very effective acrylic clearcoat is Pledge Floor Care Multisurface Finish (formerly known as Future Floor Finish).