Are you dreaming about warm summer days when your ink flows oh so smoothly? Winter and its cooler temperatures sure make it difficult for a screen printer, especially with white plastisol inks. The ink feels thick, stringy, and stiff. It requires more effort to lay down a good ink deposit. Does it have to be this hard? Nope. Ink and chemistry guru Colin Huggins shares his secrets to making white plastisol ink easier to handle during the cooler months.Â
TYPES OF PLASTISOL INK
Different plastisol inks have various consistencies: Some feel thin, others feel thick, and many are in the middle. This situation is especially true for white plastisol ink due to its varying purposes. Athletic inks, poly inks, cotton inks, low bleed inks, etc. all differ in viscosity, making some easier to print compared to others.
Plastisol inks are also either short- or long-bodied. Short-bodied inks are easy to move around. Plus, they don't leave long ink trails from the spatula. Long-bodied inks are stiffer and stringy, especially in colder temperatures. They typically leave long ink trails from the spatula.Â
Say your print shop is in your garage. On your ink shelf, you have FN-INKâ„¢, a short-bodied ink, and a long-bodied ink. You would notice a huge difference between the two inks. The long-bodied ink will feel thick and stringy, making it difficult to lay down a good ink deposit. Whereas FN-INKâ„¢ is a short-bodied ink, so it'll be easy to work with right out of the bucket. Both types of ink will work better when the ink warms up.
RELATED: 5 COMMONLY ASKED QUESTIONS ABOUT FN-INK PLASTISOL INK
WARM UP THE INK
Whether you have a long- or short-bodied ink in your shop, you'll want to warm up the inks to ensure easy printability and consistency with ink deposits and curing temps and times. If you don't warm up a white plastisol ink before printing, you'll notice that the first few prints will be thicker compared to the rest. The thicker prints will look brighter and they'll have different curing times compared to the others. Warm up the inks to make the production run smoothly.
The ink needs to hit 80°F before you start printing. There are a few options for you to pursue to achieve a warm, white plastisol ink.
OPTION #1: MODULATE THE INK
Modulating is just a fancy word for stirring. In order to warm up the ink and make it creamy for printing, you’ll need to stir it. Think of it as a printing warm-up routine — for you and for the ink. Mixing the ink introduces heat from friction, and warms up your arms in the process.Â
There are a couple of ways to stir ink in order to get it warm and creamy. You could do it manually by stirring the ink with a spatula. For larger quantities of ink or thick inks like white ink, grab a drill and an ink mixing drill attachment to stir it.
RELATED: HOW TO PREP PLASTISOL INK FOR SCREEN PRINTING
OPTION #2: LEAVE IT IN A WARM ROOM
If you know you'll be printing with white ink the next day, leave the ink in a warm room overnight. A darkroom would work great (since it's supposed to be warm). If you're doing laundry that night, bring it into that room. Wherever you know is warm, stick the ink in there to help heat it up.
OPTION #3: USE HEAT FROM THE EQUIPMENT
Another way to warm up the ink is to put the cold ink on the screen, flood it, warm up the platen to 150°, and lower the screen over the heat-radiating platen. The only issue with this method is when you put more ink on the screen, you have to go through the process again.
Lastly, some printers use their flash dryers or conveyor dryers to warm up the ink. It is an option, but you run the risk of gelling the ink. If you go this route, be cautious.
RELATED: A CHECKLIST OF EQUIPMENT & SUPPLIES NEEDED TO START A SCREEN PRINT SHOP
PRO TIP: Do not store inks against a wall that faces the outdoors. The outside temperature will cool down the walls, and the walls will pull heat away from the ink.
Until summer comes to keep inks warm and creamy, you'll have to do an extra step to ensure consistent, high-quality prints. Try out the methods and see which one works best for you. Taking this step will help you continue to power the print.