Can I use a Flash Unit to Cure My T-shirts?

Screen Printing | Nov 12, 2014

The short answer is yes, but you know there’s more to it than that. Let’s consider the issues. The real answer to this question depends on two different factors. The first factor is: what type of flash unit are you using? There are two types of heating elements. Printa Systems uses a best in class ceramic panel. This ensures that there is extremely even heat distribution and that eliminates hot and cold spots. Many other flash units are made with a wire coil heating element. It can be next to impossible to get a consistent temperature with a wire coil flash unit. If you leave the printed t-shirt or any decorated apparel under the flash too long you will scorch it. If you don’t leave the printed t-shirt under the flash unit long enough the ink won’t be cured since it didn’t achieve the necessary temperature. What happens when ink doesn’t cure? The graphic design, logo or image will wash out.

The second factor is the dwell time or the amount of time the shirt is under the flash unit. It is less production friendly to use a flash unit to cure ink on decorated apparel since it often takes twice as long to cure a printed t-shirt compared to a dryer. Part of the reason ink takes longer to cure on a flash unit is because much of the heat is absorbed into the platen. When curing decorated apparel in a dryer you are creating an insulated tunnel and reducing the amount of heat lost.

The only practical way to be absolutely sure that the temperature of the ink has been cured is to check it with a laser gun also called a laser thermometer. Having one should be required for all screen printers. That recommendation is true when using a dryer or a flash unit. It’s the most accurate way to check the temperature. Remember, ink won’t properly cure under 330F. You need to also remember that whites and lighter colors may need a little more time to cure due to the reflective nature of lighter color fabrics.