The days of wasting money on small spot jobs and slowing down cycle times due to waiting on products to cure are slowly coming to an end with the resurgence of UV products.
Over the years, paint companies have developed UV products that were a hit in the shops for technicians and owners alike who saw benefits from the technology, but they had certain aspects that made others in the field steer away from ever even trying them.
As with anything in the auto body industry, as time goes on, technology improves. There was once a time when curing UV took only a few minutes of production time but cost several thousand dollars for the equipment. It seemed for a while that only bigger shops with much larger bank accounts than the smaller “mom and pop” body shops would be able to afford the curing technology. For many, the price of the tooling needed to cure the product didn’t make enough sense in the long run, and many wound up ignoring the process and continuing on with their old ways. However, those days are long gone, and the time is now to start thinking about investing in some UV equipment.
UV Technology Explained
I’m a firm believer in understanding technology and knowing exactly what the big deal is about new things that come to the collision industry. I’ve taken this approach with everything I’ve been involved with in my years as a tech in the field. The more you and your techs are informed, the better decisions you can make as a team that will benefit everyone.
With that, let’s get down to the nitty-gritty of UV. Hang with me, we’re going to go back to school for a moment, but I promise it will all make sense.
UV light is on the lower end of the light wave spectrum. Visible light, or what we call white light, is typically around 400 to 700 nanometers. When you get below 400, you start getting into UV, which your eyes cannot see.
We all know there are several levels of UV light, called UV-A, UV-B and UV-C rays. We’ve heard this for years from our televisions talking about sunscreen and how it “blocks all UV-A and UV-B rays,” UV-A being around the 320 to 400 nanometer mark, UV-B being around 280 to 320 and UV-C being below 280. You’re probably now asking yourself, “Why is this relevant?” This is relevant because it’s all part of the greatness that’s involved with the products available to us as techs! The 1K UV products such as aerosol primers or putties for chips and pinholes all cure within those certain ranges listed above.
These UV products have a catalyst built into them called a “photo initiator.” Basically, it’s an on/off switch for curing. A primer may start curing around the 390-nanometer mark and not cure any higher than the 395-nanometer mark. A putty may “turn on” at 365 nanometers and “turn off” at 375. One of the challenges has been trying to get something to produce those wavelengths and actually cure the products as a whole and keep the price point down. The other is health concerns and protection as we already know what UV-A and UV-B waves can do to a person. Protective eyewear is a must, along with covering your skin.
One thing to consider when looking at UV application is the speed that it has when coupled with proper modern drying lights. With most common urethane-based primers applied through a spray gun, you’re averaging around six mils of build within a two-coat application. With that, you have mixing and a flash time of around 10 minutes between coats. And then you also have to look into how long it takes for the primer to fully cure before you can actually start to sand it without having to worry about clogging up your sandpaper or shrinking back, which can normally take around two hours, or a 30- to 40-minute cycle. Using the latter, now you have included a booth cycle into your time.
Let’s look at the advantages of UV. You can apply it straight into the gun with no mixing. Or, you can use an aerosol version, apply a wet coat of primer and immediately flash it with the UV light, where normal flashing is around 30 seconds, then apply a second coat and flash it again. If a third coat is needed, follow the same step, then the primer can be fully cured by holding a UV light to the surface for around a minute.
How do you dry it or flash it, you may be asking? The answer is actually quite simple: by moving the light back and forth across the panel at a distance of around four to five inches from the panel. It’s just as easy as that.
There is no longer a two-hour wait time for sanding; there is no longer the need to bake primer in a booth or heated prep deck and run up your gas bill. With one product, you can speed the entire system by hours just by using a light and still get six mils build to block down. So, there is no longer the need to spray a product and wait 10 minutes for it to flash, then wait hours for curing. The entire process from spraying to sanding can now take as little as five minutes.
Modern UV Drying
Here is what’s great about modern UV drying. These days, you don’t have to wait for the old mercury vapor-based lights to warm up and start working. I liken old UV drying tech to how streetlights used to be or the old vacuum tubes in an old TV. Remember how old streetlamps would come on and took a while to warm up and be bright enough to light our way? It’s the same principle here. But now, lights are LED-based and the energy is instantaneous. Photon energy is transferred immediately from the LED onto the surface, beginning the drying process.
Today, there are a few companies out there that are making UV lights with LEDs. LEDs feature long-lasting technology, and they’re now being used in UV technology. This, in turn, has now created a way to not only cure UV products in under a minute but also keep a lot of money in your pocket. Priced well under $1,000, a new handheld, rechargeable UV light can be carried anywhere in the shop and cure the products in record time. With newer technology available in smaller packages, valuable workspace isn’t being cluttered by big pieces of old equipment. That workspace can be used to actually turn money for the shop, as drying systems are hand-held now and can be kept in a drawer in a toolbox.
In my experiences with the newer UV drying technologies out there, I’ve been able to cure primer in under a minute and have it sanded and ready for the booth much faster than I ever thought possible. I had always been a conventional primer guy on everything, including spot jobs, but now I’ve been converted. As we all know, time is money in the paint shop. If we can’t turn hours, we can’t make money. With UV starting to pick up steam again and the advent of newer curing technology, you can’t afford not to use it.