Curing Ink & Testing Dryers

We manufacture plastisol ink. We are doing it. It's messy. Come to Louisville and check it out. This is happening. Having said this, why are we not the first phone call you make in regards to testing your dryer temperature? Oh, you called the dryer manufacturer? Bad idea. These guys are more interested in how many prints an hour their dryer can produce. Their testing methods are clearly biased towards a fast dryer belt speed and higher temperature. This makes them look good when you are producing 800 or 1000 prints an hour (I picture an equipment salesperson flexing his muscles as he brags of production capabilities). Hey, we like some of these guys but this is how they sell equipment. Fast and hot is not a curing strategy we can get behind. Too much can go wrong.

Again, we manufacture ink. Our motivation is to keep the ink on your fabric. Vibrant prints. Consistent prints. No fabric damage. Our motivation of keeping our ink looking good should tell you that listening to us about curing will keep YOUR best interest in mind. We don't want our ink washing out. Under/over curing can lead to dye migration. We don't want that either. We want you making fantastic prints you can post to our Facebook page with a smiley face emoji or a thumbs up.

Let's get into it. How are you testing your dryer? Whatever you do, don't say the thermostat on the dryer. This is an important number but not for judging the ink temperature. Are you using Thermolabels (paper thermometer), heat probe, infrared gun, something else, or nothing at all? Scratch the something else and nothing at all from your wish list. Nope. Can't do that. How about the infrared gun? This is a sticky situation and I can already feel the eye roll coming. You can't use this to measure ink curing. You can't. We know you want to. We know it's convenient. You can't. The infrared gun will only measure the surface temperature of the ink. When an ink is not cured, it is always where the fabric meets the ink. This part of the ink deposit is still "gummy" for lack of a better word. It is not fully fused. It isn't cured at the bottom. The infrared gun can't see this. We were once told this was similar to a PC vs. Mac conversation. We were against the gun out of our own snotty preference. Nope. We were against the gun out of necessity. It can't help you unless you are looking for hot/cold spots on a heat press or checking a dryer element to see if it is working. We are not questioning its accuracy, only its ability to measure where it matters. Moving on. The heat probe is accurate only when the cross wires are placed in the ink. This creates a few problems. First, it ruins the print. Those wire marks aren't coming out. Second, it can be hard with thin ink deposits to keep the wires in the ink. Finally, it is known to be inaccurate when testing dryers without forced air. Most electric dryers do not have forced air.

This conversation just lead us to Thermolabels. These paper thermometers are not perfect. However, they are the best option to ensure your ink is cured properly. This is reality. This beautiful, low tech device has been saving screen printers from bad decisions for years. The #5 package measures from 290ºF to 330ºF. This is perfect for regular plastisol ink which is most often cured at 320ºF. The #4 package is available for our low temperature inks measuring from 240ºF to 280ºF. Side note: if you aren't using our low temperature inks...you want to. Call me.

So, how do you use these wonderful little devices? First, our suggestion is always to test each and every fabric you are going to print when you are going to print them. Place a Thermolabel next to the first and last print of the order. Take these Thermolabels and attach them to the work order. This is accountability at its finest. This will save you thousands of dollars and prevent angry customers. Just do it. OK, this is important...make sure when you are attaching the Thermolabel to the fabric, you push it down firmly. Apply it on a table or platen, not the dryer belt as it is won't allow the pressure we are talking about. If it is attached to the fabric well, it will be pretty accurate. Not perfect, but certainly perfect enough to keep you and your customers happy.