Personal recommendations on best practices for heat curing Permaset Aqua from expert printer, Whitney Teska of Orchard Street Press in Milwaukee, WI. (Thanks Whitney!)

• Use forced air -  Most screen printing equipment is designed to work with plastisol which only needs to reach a certain temperature to cure.  Waterbased ink is different. Water-based inks must reach a certain temperature and stay their until the water is evacuated from the print.  A conveyor dryer and flash dryer that utilize forced air (essentially a fan system circulating air through the dryer) speed up the process and lower the risk of scorching the garment. Since the evacuation of the water causes a vapor, I find it is essential to have a second exhaust system at the rear of the dryer to suck up the vapor that would otherwise fill the room. I use Vastex equipment. Their dryers are available with forced air and you can add on the rear exhaust hood.  I assume other companies offer similar products. If not, you can obviously get one of their dryers and use it with a different make of press. They recently came out with a forced air flash dryer which I am hoping to get my hands on, but cannot attest to yet.  A conventional one does the trick… but I’m sure the forced air one would be better.
• Cure Temperature and Time -  Colormaker says they do their tests at 150 C (302 F) for 3 minutes. My set up curing waterbased inks uses a slightly higher temperature for less time. I go about 350 F for between 60 and 90 seconds. It is important to keep in mind that this is the temperature of the print when it is leaving the dryer, not the temperature the dryer is set to. To take this reading you need a temperature gun.  For example, my dryer is generally set to 700 F to maintain that temperature in the print with forced air going through the tunnel.

• Permaset Aqua Standard vs. Supercover – Anytime you are dealing with a lighter deposit of ink, you can generally cure faster.  Naturally if you are printing the Permaset Aqua Standard Inks on a white shirt, they will cure faster than Supercover on a dark garment. With light shirts I generally set my dryer to 600 F and speed it up to keep the shirts in the chamber closer to 60 seconds. For dark shirts I set it around 700 F and keep the shirts in for closer to 90 seconds. I’m still achieving the desired cure temperature of 350 F, it just doesn’t take as much juice to get there or as much time to evacuate the water from the print.

These recommendations are obviously based on my personal set up. It is vital that each individual does their own tests for wash fastness to determine if their curing set up is adequate.

TIP: I should also point out that for hobby printers there are plenty of ways to cure ink without a conveyor dryer. Some of them are explained in the attached PDF.  The first shirts I printed when I was in high school were cured using an iron or heat gun and then put in a standard dryer for 45 minutes and it did the trick. It is also possible, though less convenient, to do a final cure with just a flash dryer.  Anybody just getting into printing shouldn’t think that they have to rush out and purchase thousands of dollars of gear before they can make a single shirt.  Testing your method by washing the shirts a few times and making improvements on your findings is the most important step in the process.

–

Whitney Teska

Orchard Street Press

Some General Thoughts On Curing Permaset:

There are multiple ways that a printer can service-ably cure Permaset Inks. ** Note that a dry print and a cured print are two distinct things.

Examples of curing techniques:

• A conventional drying tunnel
• After air drying: Although the print will not melt like a plastisol ink, best to iron the back of the image.
• After air drying: fold printed garment, wrap in aluminum foil and place in a warm oven (about 190 degrees farenheit).
• After air drying: place printed garment in a clothing dryer for around 30 minutes.

All methods are subject to suit local climates, fabric moisture content, etc.  Best practice is to print a test piece(s), to evaluate throughout the curing process.

Standard Permaset lab tests are conducted immediately after printing, while the ink is still wet – using an oven at 300-320F for 2-3 minutes. If the wash test fails, the garment is inserted for another minute.

IMPORTANT NOTE: More curing does not always mean better curing…  Too much heat runs the risk of singeing the fabric  or overcuring.  (compromising the wash-fastness and dry, cracked prints)