Pad printing is the ideal process for printing on many surfaces. One of which is glass. Many decorators don’t know this and don’t take advantage of pad printing for their glass decorating needs. What decorators don’t know that printers do is that there are a couple of varieties of ink that is available and suitable for pad printing that are also fireable.

One way to use pad printing on glass is a solvent-based ink that contains glass frit and ceramic pigment. This method is somewhat difficult to use. Another option is thermoplastic inks, which have wax-like characteristics at ambient temperatures. When their temperature is raised they flow like a liquid ink.

Using these inks requires using pad printing presses that can be fitted with special heaters to keep the ink liquid. When it comes into contact with the glass bottle or container causes it begins to cool and transfer to the glass surface. Before beginning a project, check with your printer to see if their presses are capable of being fitted with the heaters.

When choosing the right plastic for pad printing there a couple of tips that can help make the decision easier for you.

Plastics vary in terms of texture and surface tension. If the surface tension is lower that the ink, the ink won’t stick. If it is higher than the ink will bond properly to the surface which will make it possible to be designed however you want.

One tip to help you determine if the plastic you are using will work is to drip some water on the surface. If the water beads up then it is not a wise surface to choose. If the water sheets the surface, the ink will adhere properly to the material.

Make sure that whatever mold you are using does not create an adhesion problem and keep the plastic free of any kind of contamination like oils, greases, or condensation. The biggest problems come from unknown surfactants that repel ink, and unidentified additives that make the plastic’s surface hydrophobic and unable to accept ink.

Sometimes when heat is applied to a component the additives migrate to the surface, changing the surface tension and the product’s ability to be printed

You know that eventually you’re going to have to pre-treat some of the surfaces that you get. The key is knowing when you need to do it, and when you can get away with not doing it.

In general, it’s best to use the ‘old pickup truck’ rule. If you drip a little water on the surface and it beads up like a freshly waxed new vehicle, it’s going to need pre-treating.

What you want is the effect that you’ve get on an old pickup truck that’s probably never been waxed and the finish is just shot – the water seems to just spread out and almost appears to soak in, drying in just a little while. That’s the sign of a good surface that won’t need pre-treating, because it’s already well-prepared to absorb the ink.

The widespread use of cell phones and, how dependent we have become on having them has created the demand for more fun options for phones. This trend is expected to continue in the future.

This creates some new opportunities for printers along with some new problems. Customized printed covers for phones with famous characters or designed is hugely popular already. People are willing to pay a lot for these covers but there are licensing specifications that have to be adhered to and the images need to be printed on a surface that is not flat.

Due to issues with the design adhering properly and the combination of the spray coatings and paint compatibility, it may take some experimentation to become good at this process. Some of this can be overcome by using an ink with lower surface tension.

Another issue is the initial spray coating may leave a dusty residue that may affect the image so a double print cycle may need to be used to avoid this situation. Although there are other challenges to printing on mobile phones, most obstacles can be avoided with a little experimentation with the products used.