Lately, our technical support team have been fielding numerous questions about doming. "What is doming?" "What materials can be domed?" "Can you dome printed vinyl?"

This article will provide answers to such questions, so you can decide whether domed badges are suitable for your business.

Doming is the process of adding a glass-like, plastic-resin bubble to a 2-D surface, which transforms it into an eye-catching, 3-D product. For a small, additional price, you can simulate the appearance of a vacuum-formed or moulded part, without having to pay for expensive tooling and production equipment.

Duro-Lenz label coating is normally confined to self adhesive vinyls and polyester materials. However, they are not the only materials you can dome. Just about anything that isn't porous – metals and plastics such as acrylic and polycarbonate will work. Note: Anything that's porous can absorb moisture from the air and cause bubbles to form in the doming liquid. Therefore, substrates like paper are unsuitable for label coating.

The label coating acts as a lens and magnifies the printed image’s brilliant colour. Its’ light-diffracting effect creates a very elegant appearance. Even with standard single colour graphics, doming makes something ordinary appear extraordinary. Domed badges are simply another way you can differentiate your products from the competition.

What doming resin systems are available?
Resins typically fall into one of three classes of materials: epoxy, UV-curable resin and polyurethane. Within each classification, several products are available. For outdoor applications, most companies that specialize in doming such as Duro-Lenz, choose polyurethane. After comparing each material's performance characteristics, you'll see why polyurethane is the best choice.

Epoxy resins are popular for doming metal key tags, plaques etc. Available as one or two part systems, epoxies are inexpensive and easier to use than other materials. Because epoxies cure slowly, air bubbles trapped in the resin often rise to the surface and disappear, forming a bubble-free finish.

Because sunlight yellows the clear, plastic material, epoxy resins aren't suitable for outdoor use. Plus, due to their softness, epoxy resins can be easily scratched.

Next are UV-curable resins, which fall into two classes: low and high intensity. Although low-intensity doming liquids cure when exposed to black light, others require high-intensity UV curing units.

UV resins work similarly to UV-ink systems. Exposure to UV light initiates a photochemical reaction that quickly hardens the liquid. In contrast, other resin types require hours, and sometimes days, to fully cure.

Low-intensity, UV curable resins harden after being exposed to a black light (the same type of black light common to the '60s and '70s hippie era). Low cure resins don't withstand prolonged outdoor exposure -- after six months in the sun, they begin to yellow. As UV exposure continues, these resins cure and harden until they become brittle and crack.

Duro-Lenz use two-part polyurethane label coating systems comprising a resin and an isocyanate curing agent that hardens the doming liquid. Although working with polyurethane resins is typically burdensome, such resins can withstand outdoor rigors.

Because they resist yellowing, polyurethane resins are suitable for vinyl graphics and other signage applications, including OEM decorative emblems, nameplates and labels.

In addition, the material remains flexible and doesn't crack, craze or flake. Polyurethane resins not only weather well, but they also block UV light and, in turn, protect the material they cover. This means the base substrate and printed image will survive longer outdoors.

Companies that specialize in domed graphics, such as Duro-Lenz conduct their doming operations in a clean room with controlled temperature and humidity. Our doming room maintains a temperature of around 20° C and relative humidity of 50%. Temperature, as you might imagine, plays a big part in the curing process. Curing can actually be accelerated at elevated temperatures. We have a special drying room for this process.

Almost any standard shape (rectangle, square, oval, elipse, circle etc) can be domed. For simple shapes, such as circles, we dispense a measured amount of liquid into the center of the decal, and allow the resin to flow out to the edge and level out. This might require 5 to 10 seconds. A domed part's height will be around 1.8mm. Generally, it's better to round, rather than square off, corners of lettering or graphics. With patience and a steady hand, we can dome some more difficult shapes but the cost per part is higher.

Doming polyurethane resin has a high surface tension which binds it together. When applied, the resin flows out until it hits the part's edge. At that point, the doming liquid hangs on the edge for dear life. The resin spills over the edge if you apply too much liquid, and the liquid's weight exceeds its ability to hold itself together. Spillage is rare at approximately 1%.

Duro-Lenz has two resin systems. One is dry to the touch in two hours. The other system is not touch dry for 12 hours and post cures for up to 3 days thereafter. If the resin isn't completely dry, you'll likely leave a fingerprint.
After the resin is completely cured, it's very tough and can even resist scratching and abrasion.