Why IR Curing Actually Matters for Aircraft Coatings
We use short-wave infrared (IR) lamps to dry our aerospace coatings. Now, on the surface, it looks like we’re just trying to move planes through the hangar faster. But it’s deeper than that. The way IR heat hits the paint actually changes how the plane handles a bird strike or a spray of gravel at 500 mph.
Getting the chemistry right
Think about a standard convection oven. It heats the air, then the surface, and then the heat slowly creeps inward. It’s a slog. IR lamps are different. They send electromagnetic radiation straight through the coating. It hits the bottom and the top at the same time, triggering the curing process everywhere at once. When the coating cures evenly from the metal skin all the way to the surface, it doesn’t get as brittle. That’s the key. A brittle finish just snaps under the pressure of an impact. But an IR-cured finish has enough “give” to soak up that energy and stay intact.
It’s a balancing act
You can’t just crank the heat to max and hope for the best. If you blast it, you’ll burn the resin. Then you’ve got a coating that flakes off the moment something touches it. We spend a lot of time tweaking the wattage and the distance of the lamps to get the temperature ramp just right. Short-wave IR is powerful. It gets the polymer to its transition temperature fast. That’s a good thing. If you go too slow, solvents get trapped in the bottom layers and create tiny little bubbles—micro-voids. Those voids are trouble. They act like little stress points. One tiny pebble hits a void-filled coating, and the whole thing can shatter.
The tricky parts
There are a few headaches that come with this. These lamps pull a massive amount of power. If your voltage isn’t steady, the lamps flicker, and you end up with uneven “stripes” in your cure. Not a great look. And you have to keep a close eye on the aluminum. If the skin gets too hot, you risk warping the panel or ruining the bond with the primer. It’s all about finding that sweet spot between lamp intensity and the cooling cycle to keep the part stable and the finish tough.