Screen printing heat transfers can seem daunting but in reality, it’s fairly simple. If made properly, plastisol heat transfers can last almost as long as a standard screen print and can be much easier to apply in certain scenarios like decorating hats, neck labels, names for sport apparel, and more.
Let's walk through the basic components and process of screen printing your own heat transfers.
THE TRANSFER PAPER
The first step you're going to do is run the transfer paper through a conveyor dryer. Paper absorbs moisture from the air. The transfer paper needs to be dry so it doesn't interfere with the ink. Don't get the paper too hot or you'll get ripples on the paper. For multicolor heat transfers, flat, stable transfer paper is a must.
You do not want to push on the squeegee too hard. If you push too hard, the ink will seep out the sides of the stencil. You need to put just enough pressure to clear the ink through the screen while maintaining sharp, clean edges on the print. This is probably the most important takeaway you should have from this video.
You also need to be careful about avoiding printing a stencil that's too tall. If it's too tall, the ink will smush when it's heat pressed. To control the ink deposit, you'll have to do some trial-and-error. Play around with mesh count and how thick you coat the screen.
THE ADHESION POWDER
To coat the transfers with the adhesion powder, you'll first need a container to hold the powder. Colin uses a simple plastic storage box for this purpose.
Fill the box with a good amount of the powder. Dip the paper into the box and run the powder over the ink a few times. When it's completely covered, flick the paper to dust off any extra powder.
Pro Tip: Your fingers have oils, which can transfer onto the paper. Wear gloves to avoid that issue.
Once all the transfers are covered with the adhesion powder, pour the remaining powder back into its original container. You don't want the powder to sit in the open box because it may soak up moisture from the air. If it soaks up moisture (you'll be able to tell by its sandy texture), it's time to toss it. Always store the adhesion powder in a dry environment.
GELLING THE INK
Nope, you are not curing the ink. You want to gel the ink (curing will happen when it's time to heat press it). Since Colin uses FN-INK™, a low cure ink, he runs it through the dryer at 200°F. For standard plastisol inks, shoot for 260°F.
Conveyor dryers provide more consistent heat compared to flash dryers. When using a flash dryer, you have no control over the zone of heat. The middle of the flash dryer is much hotter compared to the outer edges of the unit. Since the middle is hotter, the ink there will reach gel temp much faster than the outer edges. While waiting for the edges to hit the gel temp, the middle may reach cure temp. Conveyor dryers are the best route for gelling heat transfers.
When setting up the heat press, Colin sets it at 350°F with a four or five pressure. The settings will differ depending on the type of transfer paper, adhesion powder, heat press you are using. Wash test to discover which method works best.
In the video, Colin applies the heat transfer to a 100% cotton garment. Cotton can absorb moisture. Colin preheats the garment to remove any moisture and smooth out the fabric. He presses it for about five seconds.
Make a notch or some sort of indicator to note the middle of print so you're able to align it on the shirt. Lay the paper on the shirt and press it for 10 seconds (or whatever you discover works best for your tools and equipment).
Colin uses a hot transfer peel, so he removes the paper as soon as he finishes heat pressing the shirt.
That's all there is to it! With the right tools and a little bit of know-how, you'll be able to create your own plastisol heat transfers in no time.