Last Updated on October 6, 2021 by Dave Farquhar
Rustoleum paint claims to bond to plastic. This is a good thing, because traditionally, plastic has been a bit difficult to paint at times. So are the claims true? Does Rustoleum plastic paint work?
The current formula is different from the old one
I know people who have been using various hardware store spray paints for decades who don’t like the current Rustoleum paint. They say it doesn’t work.
The formulations do change from time to time, so not knowing what they are used to, and not knowing their technique, I can only speculate about why they’re getting unsatisfactory results.
I will say if you use the paint wrong, you can get unsatisfactory results. I have. I’ve also gotten good results. So let’s talk about how to get good results and not repeat my bad results.
How Rustoleum plastic paint works
All paints contain solvents. That said, the formulation of the solvents makes a difference. The major difference between the current rustoleum paints that bond to plastic and the old-fashioned stuff that just called itself plain old paint is the formulation of the solvents. Some solvents will melt plastic. That may be the source of some people’s problems. I know that was the source of mine.
The idea is that the solvents soften the plastic, make the plastic itself sticky, and cause the pigment to embed itself into the plastic rather than just sticking to the top layer.
What I found is that if I apply to heavy of a coat, the paint melts the plastic and changes the texture. The way you avoid this is by applying light coats. Don’t let the paint pool on the surface. Apply a thin coat, let it dry about an hour, then come back and apply another coat. Repeat until the color and smoothness are consistent.
If I had to guess. People not getting good results with the current formulation is probably from using too thick of a coat.
That said, there are a few more tricks, but these tricks haven’t changed much. I imagine someone who was painting in the ’70s knew these tricks.
The prep work that hasn’t changed since the release of plastic paint
Any paint works best if you shake the can thoroughly to mix it and if you warm it up to a bit above room temperature. If it’s hot outside, simply leave the paint can sitting out in sunlight for an hour or two to warm up.
This also helps you mix the can. To mix the can, shake the can vigorously to free the metal ball inside. The ball is what mixes the paint. If the ball is stuck, that means all of the pigment is stuck in the bottom of the can. Once you free the ball and you can hear it rattling around while you shake the can, alternate between shaking the can and rolling the ball around the bottom of the can. To do this, hold the can straight up and down and make a stirring motion with your arm, like you were stirring a big bowl of something.
How long to shake the can may vary. The instructions on the can may tell you a specific length of time, say 2 minutes. The nice trick about warming up the can ahead of time is that if the paint isn’t thoroughly mixed, you will feel the temperature of the can changing as you mix it. When you can shake the can for 5 or 10 seconds and not feel the temperature change, that’s a pretty good indication that you have mixed the paint well.
Surface preparation is also important. If the surface has dirt or oil on it, that will interfere with the paint sticking. It will also give an uneven surface. Before painting, wipe the surface down with a good cleaner. I generally use alcohol, but if the surface is especially grungy, I may use mineral spirits. But usually you can get by with window cleaner if that’s all you have. Wipe it down, let it dry, and then don’t handle it again with your bare hands. Wear rubber gloves if you need to pick it up and move it.
Mineral spirits are a good thing to keep on hand anyway. If the nozzle gets clogged, you can pull the nozzle off the can, put it in a small jar or container with some mineral spirits, and let it soak for a couple of hours or overnight. The mineral spirits will soften the clog and allow you to reuse the nozzle.
To help keep the nozzle from clogging, pulled the can upside down and spray when you’re finished.
There’s one more thing I can’t emphasize enough. Practice on something you don’t care about, and when you are painting something you do care about, take your time. Don’t get in a hurry.
Plastic is everywhere. So hopefully you know what kind of plastic the item is that you are painting. To find plastic to practice on, book up the plastic recycling codes. Every piece of plastic consumer packaging has a recycle code on it. Save some junk plastic that matches what you plan to work on, and then practice painting the junk before you paint the item that you care about. It’s no big deal if you ruin something you were going to throw away anyway. All you’ve wasted is a few cents worth of paint. The experience is worth it.
The same paint works on wood and metal too. It just doesn’t bond to it like it does with plastic. But the different formulation means that it will behave differently than the old stuff did if you’re trying to paint wood or metal. The tricks are still the same essentially, but of course the paint won’t melt wood or metal.
If you haven’t painted in a while, or if the packaging says it’s new and improved, or it’s not your usual brand, the trick is to practice on some scrap to get a feel for how this formula works. Every brand can be a little bit different, and this year’s formulation maybe different from the last one that you have.