In a recent article, one of our commenters recommended painting an antenna black to help ice melt. Several years ago, I came out generally against painting antennas. So, let’s take a closer look at why this would or would not be a good idea.
It starts with understanding paint.
Paint is a very interesting thing. Paint is, by definition, something that coats something with color and then sticks. It doesn’t actually change the color of something. That would be dye. Paint covers. Ideally, though, paint sticks to the surface so well that it doesn’t come off.
So, one of the things that we know about painting metal is that painting bare metal doesn’t work very well. Metal is smooth and hard. Paint doesn’t stick to it very well. In fact if you paint metal without doing something to it first, you’ll invite oxidation. That’s really more of a problem for iron than it is for aluminum.
So, in order to make paint stick better, we use primer. Primer is really just another form of paint that sticks better to surfaces. Primer for metal surfaces is designed to get into those little microscopic spaces and stick hard. Then the paint can easily stick to that.
Then you have to understand pigment.
Pigment is the stuff that gives paint its color. The science of pigment is one of those things you could get stuck in for decades if you wanted to. But, let’s try not to. So let’s just say there are two kinds of pigments: organic and non-organic. Organic pigments aren’t as effective. They come from flowers or plants. Non-organic pigments are flakes, often of metal, and they work a lot better. Non-organic pigments are brighter and they stay that way longer.
The problem with non-organic pigment, in this case, is that you’re taking flakes of metal and putting them in a goopy solution. This can cause signals to bounce back in weird ways instead of being received by the antenna.
And then you have to understand color
See, the commenter mentioned that he paints his antenna black. This makes sense. Black pigments absorb color instead of reflecting it back. Black absorbs the most, while white absorbs the least. So painting an antenna black makes sense for two reasons. First of all it’s going to mean the antenna absorbs the most infrared radiation. This going to make the antenna hotter and that’s the point. The ice will melt.
However the other thing about black pigment is it’s most likely to allow all those signals through. It won’t bounce as many of them back. Black paint is more likely to have fewer of those metallic pigments that reflect light back. So it does make sense that way too.
And then… you have to go back to primer.
Most primer is white or grey. There is black primer, but it’s not as common. If you choose white primer, you’re probably limiting your antenna’s effectiveness. It will bounce back more radiation and that includes antenna signals.
So I’m guessing the commenter is either using black primer or no primer at all. Using no primer at all isn’t going to hurt in the short term and I think it probably is better for preserving your antenna’s effectiveness. Most likely the paint is going to flake off in time but you can always repaint.
Unless you really know what you’re doing with paint formulations and you’re willing to do some trial-and-error, I still stay with my position of not painting an antenna. But hey, that’s what DIY is all about. If you want to try it, try it! I’d love to hear from some other antenna fans about their own experiences.