The application of UV and its acceptance in the collision industry has been a little more tenuous. Initial testing began years ago, but there were issues that had to be overcome. Today, the technology has improved to the point that it can be a viable option to handle small, usually one-panel, repairs. While it may not yet be the best choice for large repairs, or overall refinishing, this technology is promising due to its ability to significantly cut cycle times. It is possible to fix a small ding or scratch, prime, and paint the repaired panel, and deliver the car using UV in less than one hour. For this reason, plenty of interested shop owners and managers are looking more closely at the UV process. You should too.
The basics
UV curing works through a chemical process, activated by the energy of ultraviolet light. The light crosslinks (cures) liquid product molecules, and "force" dries the product in less than one minute. Unlike chemically or heat-cured finishes, UV-cured surfaces dry extremely quickly, to the point they can be worked with, in minutes, including buffing.
Even though the UV paint curing process is much faster than drying conventional paints with IRT technology, or using the bake cycle on a booth, there is virtually no risk of deforming or melting plastic parts such as bumper covers or trim pieces due to high temperatures. UV lamps do generate a small amount of heat. If the lamp is positioned correctly on the surface being dried, any heat produced will be minor and certainly not enough to cause damage.
Product availability
In general, there is a limited number of UV-cured products currently available in the market. These include primers, aerosols and sprayables, putties (used for minor repair) and clear coats. There are no UV basecoats available for automotive applications at this time. Each of these products typically is part of a one component, or non-catalyzed system, so they have an extended shelf life (1-2 years).
The most common and readily available product is the aerosol UV-cured primer. It is easy to use and has become a favorite product for painters at Collision Centers of America. I interviewed several painters at their high volume, Schiller Park location, where speed and quality are extremely important. Matt Wagner, head painter there, said, "I can prime a small spot, hit it with the light, and scuff it in minutes. It really speeds up the cycle time on small jobs, to a point where it's almost unbelievable." In this facility, they do a great many drivable, smaller repairs that fit well with the qualities that UV can provide.
These primers are available from a number of manufacturers. Since the primer is in an aerosol can, it is really easy to use anywhere in the shop. An added benefit is that the overspray is safer, and without activation from a UV light source, can almost be wiped off anything it hits with a clean rag. Some manufacturers do make a primer that can be sprayed with a conventional gun, so that larger areas can be primed as well. Ask your jobbers about what lines they carry and experiment.
Glazing putty
UV glazing putties are used primarily to fill small surface imperfections in vehicle panels and can be used over polyester body fillers. They are usually compatible with most brands of automotive primers and sealers. As long as UV glazing putties are not exposed to light, their shelf life can be as long as one or two years. Some putties are not pigmented and are essentially clear. They work well due to the fact that the UV rays can penetrate the entire product completely through, offering a more thorough and faster dry time.
These putties are not high build and will fill only small imperfections. As with the primers, once they are exposed to the rays of a UV light source, they dry without being mixed with any hardener. In a minute, they're ready to sand. They tend to sand well, although if not cured properly, they will roll up like uncured filler does. Following the manufacturers' directions is imperative. The putty is applied with a standard or rubber spreader. Do not put the product on too thickly. Apply it as you would a standard polyester glazing putty. Once it is applied, position the UV lamp over the repair area. In about a minute, the putty will cure and be ready to sand.
Clear coats
UV-cure clear coats are "water clear" after curing, so there are no color altering or yellowing effects caused by these coats during refinish operations. UV-cure clear coats have built-in UV protection to resist damage and surface degradation caused by the rays of the sun. They also have superior gloss retention, durability, and have excellent scratch resistance. Until these products are exposed to light, they will last a long, long time on the shelf. There are several types of clear coats available, including a one-part clear and a two-component clear that dries with UV light and also utilizes a catalyst. These two-part clears are better suited for refinishing larger areas than one component clears.
The application of UV clears is fairly conventional and similar to the process of applying a standard clear coat material. These products have a fairly short tack time so they are resistant to airborne grit and dust. Once the lamp is applied, the paint dries almost instantly. As soon as the lamp is moved away from the repair area, the painted area can be sanded and buffed. There is no waiting for this operation. In fact, if there is a problem with the repair, it can be recoated right away after cure without any fear of lifting or reaction of any kind. Even if a conventional system is used later in the same repair area, there will be no issue with lifting or product compatibility.
Final thoughts: Stranger than fiction
If your shop runs a fast lane or specializes in smaller repairs, you might want to consider the UV process. You can conceivably have a customer come into your shop to have a small scratch fixed and sit in the waiting area for the 45 minutes it would take to do the complete repair using UV technology. I watched a small ding in a front fender of a BMW be repaired, primed, painted, buffed and detailed in 37 minutes, from start to finish. The repair quality was exceptional. The waiting customer actually was a little agitated when the vehicle was delivered to him because he didn't have the opportunity to finish the story he was reading in a magazine (the manager sent it home with him).
In its current form, UV technology shines in these specific areas. As this technology develops, I can see greater applications of it in the future. I suggest you start your UV experiment slowly by using the UV primers as a start. Get your staff used to them, and see where it goes from there. This technology has some exciting potential. If it can deliver just some of what it promises, watch out.
