Screen printed transfers can be a useful tool for a wide variety of applications. Consider transfers when you are on location for an event as you won’t have to pre-print any apparel that may or may not sell. Consider transfers when you don’t have a special platen for a can cooler, face cover, or bag. Consider transfers when you sell goods in web stores and you want to fulfill very quickly at the close or as orders come in. Long story short, even if you are not a transfer printer, you should be printing transfers or buying transfers from a professional transfer printer.
I will have numerous blog posts coming out in the coming weeks with specifics about different types of transfers such as cold peel, hot peel, hot split, and low temperature. Although there are four types of transfers, there are so many inks, papers, adhesives, and processes that you can create a number of different looks and feels. This blog is about the basics.
Transfer paper is the beginning. Every transfer paper behaves differently with a purpose. Each has a special coating. A hot peel paper lets go of the ink once it reaches a certain temperature by the heat press, but only when it above this temperature. The opposite is usually true with cold peel paper. It only lets go of the ink when it has cooled down. Hot split paper has little to no coating which allows the ink to “split”. Half the ink stays on the paper and half on the apparel.
Shrinking transfer paper is a big deal if you plan on printing more than one color. You need to both shrink the transfer paper and keep it shrunk if you want excellent registration. Shrink the paper by sending the paper through your conveyor dryer immediately before printing. Keep it shrunk by printing quickly. Your enemy is humidity. As the paper sits out in the open air, it is slowly expanding due to the moisture. A way to slow this down is to keep the shop dry. You can also keep the paper in a hot box once it has been shrunk. This will slow the expansion process.
Moving onto inks, you have a number of options. A true transfer ink is our 380 Series. This is the best ink for hot split transfers. It will also work well for hot peel and cold peel transfers. Once you get out of this ink series, you really need to know exactly what your process, paper, and adhesive you may use. I will offer up a number of options for different inks and transfer types going forward. However, with premium hot peel and cold peel papers, you should be able to print any ink if you are also working with a powder or liquid adhesive. Your process will matter. Regardless, choose an ink as you normally would. Bleed resistant inks for polyester. Soft inks for a soft feel. You get the point.
Adhesives can be an important part of your transfer. Powder and liquid adhesives will increase the durability, opacity, and bleed resistance of the transfer. A liquid adhesive such as our 380 Printable Adhesive is printed over the entire image as the last step. Powder adhesives are dropped on to the wet image through a variety of techniques as the last step. For the powder to work, the entire base layer of the print must be wet. Some art will not allow this naturally so you will print a clear ink over everything and then drop the powder. Many of you are thinking about that liquid adhesive right about now to save a step and some trouble. Powder is my preferred method as it will allow for ultra-low temperature transfers. It will also provide better stretch and bleed resistance.
Equipment for screen printing transfers is similar but different. You only need a one color press and a vacuum platen. I know this sounds odd. Obviously, if you are using a multiple color press, that is also okay. The vacuum platen stays though. For speed, you will want a vacuum with a foot pedal attached. This way you can simply turn the suction on and off, working much more quickly than someone with a vacuum running at all times. This makes it hard to load paper.
Speaking of loading paper, you need three points of contact to ensure the paper is always placed on the vacuum platen in exactly the same place. This plus paper that is fully shrunk is critical for good registration. Glue some washers down to the platen. Two on the bottom and one to the right or left. This way you place the paper down to the two washers and then slide it over until you hit the side washer. Perfect loading.
Finally, we are talking about the printing process. Artwork first! You must mirror image the art work as it is backwards of normal printing. This also means you print darkest ink to lightest. Use the darker colors to trap the lighter colors easing your stress about registration and paper expansion. You will print the darkest color and send it through the dryer. With most transfers, you are simply “gelling” the print. You want it dry to the touch, not fully cured.
Once you have printed all of the sheets you need for the first color, load the paper back onto the press and register the second color. You print one color at a time. No flash cure unit. I know a certain someone is online with videos using a flash cure unit and a multi-color press. He uses a platen with spray adhesive. This is a mistake as I can print 500% more transfers in the same amount of time. I also won’t leave glue residue all over the back of the transfer paper to pass onto the heat press. Stick to the plan.
The final ink will typically be a printable adhesive which covers the entire image or a clear ink which will do the same. The clear ink is just there for the adhesive powder to stick to. If there is a light colored outline around the entire image, you can use this as the base to all colors and simply powder it. Going forward you will learn more to know if you need a printable adhesive or a powder adhesive. Sometimes you will not need either.
Visit the blog regularly to learn every type of transfer in far greater detail. I will dive deeper into specific methods, supplies, and settings so you can print along with me and figure it all out. In the end, you will create a transfer using your own ink, paper, adhesive, and heat press settings. You will have the basics to experiment. This way you can have a transfer that fits all of your needs.
Director of Product Development