We talk a lot about the protective element of powder coating. It’s ideal for outdoor parts, for instance, because powder coating creates a barrier against the elements, protecting the part from damage.
But there’s protection, and then there’s PROTECTION.
Parts for automated car wash systems need PROTECTION – protection from almost constant exposure to water and chemicals, in addition to the wear and tear inflicted by vehicles, heat, and abrasive surfaces.
Kaser Blasting & Coatings has one customer in particular for whom we powder coat a lot of car wash parts, for automated systems all over the country. We love working with them, because it presents a unique set of challenges.
For one thing, our powder coating process is very different for these parts.
We start by blasting the parts to near-white metal. Most of the parts are steel, and are blasted with steel grit; aluminum parts are blasted with crushed glass. Since the customer has specified that they don’t want pretreatment, we hang the parts after blasting, and blow them off to remove any residual blast media.
After that, they go in the oven. Why? Because we have to get them hot before spraying.
Our customer requires their car wash parts to have a tremendous film thickness of approximately 15 mils; 10 mils of primer, 5 mils of top coat. Normally, in order to achieve 10 mils of thickness, we’d spray two or three separate coats, gelling the parts in the oven between coats. Since that’s time consuming and costly, we’ve learned that spraying a special epoxy primer on a hot part allows us to build that film thickness in one coat.
The primer starts to gel immediately on the hot part, and as long as the part stays hot, we can keep building film thickness. If we were attempting this on a room-temperature part, the surface would stop accepting powder pretty quickly. After about 6 mils, the part would be too charged and the powder would start falling off of it.
Powder coating a hot part is not easy, and a lot can go wrong. For starters, there’s a safety issue, both for the applicator and the spraying equipment. Secondly, the thicker the film, the more prone it is to drips, sags, and other issues that don’t always manifest right away. We have some talented sprayers on our team, who have tried, failed, learned, practiced, and taken detailed notes on how to achieve the best results.
Masking these parts is equally challenging, since the masked portions are getting coated with a very thick coating along with the rest of the part. When we first started, we’d have to literally break the powder coating to access and remove the masking, and it took forever to peel. Now, we leave tabs and access points for ourselves, so that peeling the masking goes much more smoothly.
If the part cools down too much during spraying, we’ll have to put it back in the oven to complete the gelling process. If we’re able to spray everything while it’s still hot, there’s no need to put it in the oven before the top coat. Once it’s cool, we’ll spray a top coat (5 mils thick) in the color the customer wants. Then the parts go back to the oven for final curing.
Next time you’re going through the car wash, take a look around and think of us. The parts you see weren’t easy to coat, but if they were done by Kaser, you know we had fun doing them.