Prime Time: That Which Lies Beneath the Paint

Krylon Gesso Spray and Tamiya Fine Surface Primer

With NaMoPaiMo coming up, I thought I'd start a series of posts on some of the finishwork materials and techniques I use. Since a lot of people are probably in the process of prepping right now, I thought I'd start by talking a bit about the types of primer I like. Different people like different kinds of primer, and the most important thing is finding something that works for you. 


I mostly use two types of primer on my models. The first is Krylon Gesso Spray. Some people like to use brush-on gesso, but I have trouble getting it even, despite working in thin layers.



Jadakiss resin primed with Krylon spray gesso

The spray gesso has a very nice chalky matte finish, goes on evenly, and usually only takes 2-3 light coats. It sands very nicely, which I think is an important characteristic for primer. In my experience it adheres to the models a lot better than the brush-on stuff I've tried, which tended to chip if I tried to sand it.

One thing that can be a drawback with gesso spray is that it's a bit thicker than some of the other primers. As long as you work in thin layers, it's not usually a problem, but if you're not careful it can start to fill in smaller details.



Customized Truffle resin primed with gray Tamiya primer

That's why for models with a lot of fine sculptural detail, I like to use a different kind of primer: Tamiya Fine Surface Primer, which comes in two colors: gray and white. Sculptural details tend to stand out more with the gray primer, which is very helpful when prepping, but in general I like painting over a white base better.



Customized Breyer Ruffian in progress, sprayed with a coat of white Tamiya primer and then sanded

Tamiya primer goes on in thin layers, which preserves fine detail while still giving you a nice opaque base layer to paint over. It's more expensive than spray gesso, and its finish is slicker with a slightly semi-gloss shine. It's made to prime plastic and metal, and so sticks to models very well. It also sands nicely.

 

In addition to helping paint adhere to the model and providing a uniform base to apply color over, primer can be used while resculpting to better visualize what's going on with your sculpture. In-progress resculpts are often several different colors, with patches of epoxy putty, OF paint, and bare plastic. Adding a coat of primer can make things a lot easier to see, just make sure to keep it thin (I like the Tamiya primer for this.) It's also a good idea to make sure to remove any primer before adding epoxy to an area, just to make sure it sticks well and there aren't any problems with the epoxy lifting later on.

 

As far as actually applying the primer, the most important thing is to follow the instructions on the can, especially any safety precautions. I like to spray outside and use a respirator mask. It's important to work in thin coats, which I know is really hard when you're anxious to finally be done with prepping! 

 

If you try to prime the horse in one coat, the primer is almost certainly going to run or sag, and might end up pooling in depressions, obliterating detail. It usually takes me about three sessions to prime a horse, maybe more if I miss a spot. How long you have to wait between coats varies, and it's a good idea to follow the suggestions on the can. Generally you want the primer to look completely dry.

 

If you do end up with drips (which you probably will at some point, even if you're trying to be really careful) wait until the primer is completely and totally dry (usually this means sometime the next day) and use some fine grit sandpaper to gently sand the drip. Then dust off the model and prime the area again. Trying to sand primer that's not completely dry will probably result in the primer lifting in chunks rather than sanding smooth. If this starts to happen, just put the model down and give it a few more hours to dry, then try again.