To set up a complete tinting system, you’ll need a heating unit and a gradient tinter. The basic heating unit comes with the heating component and dye vats. The gradient unit comes with a device that enables you to dip lenses into the vats at various timed intervals to create gradient tints, solid colors and special effects.
While there are some gradient tinting units designed to work with specific heating units, you can usually mix and match the two components as per features and costs.
Probably the biggest concern for gradient tints is the consistency of the gradient, which means a result that shows no lines. There are two basic types of gradient tinters; stroke/CAM units and electronic units. Stroke units operate by a motorized CAM system that raises and lowers the lenses in and out of the dye a specified number of strokes for a specific time.
Electronic units, which are typically more expensive, offer functions such as automatic timers with sound and automatic lift-out mechanisms. These are important features for the busy dispenser who wants to be able to set up gradient jobs and walk away.
Assess Your Needs
When purchasing a tinting system, consider your current tinting needs, potential needs and the level of selling and promotion you plan to initiate after purchasing the system. For example, if all you require at the moment is a system equipped with quart-sized vats, ask the vendor if the system can be expanded to handle pint-sized vats as well. That way, you can boost your ability to tint more lenses in a larger variety of dyes at one time. Keep in mind the mini (two-vat) systems are designed for extremely low volume (one or two jobs a day), while the half-gallon systems are designed for high volume (a couple hundred jobs a day). Also, some six- and eight-vat systems are dual-controlled, meaning the entire system doesn’t have to be heated at once. If you have a day where you don’t require as much tinting, you can leave one side off. This will save on supplies and cleaning.
The most important feature of the heating unit is its ability to maintain a consistent and proper temperature. For quality lasting tints, the heating unit needs to get the dyes to at least 205°F.
The dye vats are usually heated by a method that resembles a double boiler cooker. A chemical known as heat transfer fluid (HTF) is placed in the “outside” tray surrounding the exterior of the dye vats. The HTF gets hot, stays hot and in turn, heats the dye.
Some companies recommend using water instead of heat transfer fluid. If you go that route, make sure the system you purchased is capable of using water.
The main argument against using water is that it boils at 212°F, which encourages evaporation. That could result in a loss of heat, inconsistent dyes and damage to the unit if not carefully watched. The main benefit of using water is that it is inexpensive and doesn’t leave a mess. Some manufacturers have tackled the evaporation problem by creating larger reservoirs that hold more water.
Another heating option is direct heating, which is similar to using a hot plate. With direct heating, it’s important to make sure neutralizer or UV coatings do not drip on the hot plate, because it may create a fire hazard. Heating from the bottom of a vat may also crystallize the dyes.
Magnetic induction heating is another direct heating option. This method not only heats from the bottom but also all around the vat. The process uses electricity and works similarly to a “no burner” stovetop. The main benefits are no HTF, no fire risk and no fumes.
At least one manufacturer offers dyes that can be heated in a standard microwave oven. (Keep in mind that you’d also have to use microwaveable containers.) Proponents of using the microwave say it’s fast; polycarbonate lenses can be tinted to a medium shade in six minutes.