I want to prime a balsa kit before painting with acrylic. Can I use rustoleum plastic primer? Its what I've got.
I think Rustoleum would be too thick to penetrate and seal balsa. Model paints are much thinner and penetrate better.
I've used rattle-can primer on balsa rocket fins before, and it's fine as long as you use several extremely light coats and let it dry well before painting. That said, the plastic-ready primer is a different formula. I've never tried it on wood, so that I don't know about. Primer is cheap, I'd get the regular stuff.
I wouldn't. Get some Z poxy finishing resin at your local hobby shop or one of the online places like Tower Hobbies. Get the smallest size you can, a little goes a long way though the shelf life seems to be excellent. Brush it on with an acid brush or other disposable brush but not a foam brush. Wet sand it with a 440 or 600 grit wet/dry paper and then paint it with whatever you want. Rick H.
Some questions: Is your project actually balsa or is it basswood? Balsa is super light, and not normally used for model railroad kits. Balsa will soak up a lot more paint than basswood. What is the final project supposed to look like? Is it a model of something like a wooden building or is it a model of a steel boxcar. If it's a steel boxcar you want to hide the woodgrain, so maybe a few coats of shellac followed by sanding is in order before the color coat. For buildings made of basswood I have just painted them with the acrylic, then sometimes lightly sanded them to get rid of any fuzz and given them a second coat. The problem you can encounter is the wood will warp from the paint if it's not suitably reinforced. If the wood is not reinforced, a thin coat of shellac on both sides can seal the wood so it doesn't soak up so much paint but still leave some wood grain showing on the finish side. These words are simply my personal 2 cents! George V.