Answers to frequently-asked questions
It's been almost a decade since black neoprene and brown buna-N squeegees were supplanted by color-coded, high-density polyurethane squeegees. High-density blades resist the corrosive effects of inks and solvents, while the color coding (indicating the blade hardness) is especially useful in shops that print with a variety of inks and substrates. For example, a blue bullnose for dark-garment printing is easy to distinguish from an orange square edge used for halftone printing.
Some squeegees are composed of more than one material. To prevent roll-over from excessive squeegee pressure, printers used to shim soft blades with strips of aluminum. Today, some squeegees are available with a stiff material (a fiberglass sheet or hard polyurethane) between two layers of softer polyurethane. This provides the more flexible printing edge of a softer blade, while reducing the blade deflection. Some composite squeegees also come with a rigid material in the top two-thirds of the blade, while the softer polyurethane is on the bottom to serve as the printing blade.
What is Squeegee Durometer?
The durometer of a squeegee is the measure of its hardness, and a guide to the blade's ability to resist bending during printing. Squeegee durometers are measured on the Shore A scale, an industrial standard of 1-100 used to indicate the hardness of rubbery materials. The higher the durometer, the greater the blade rigidity. The lower the durometer, the more the blade will flex during printing.
You need to know that the instrument used to measure durometers is itself called a durometer. This device has an indenter pin, which is pushed onto the surface of the squeegee. The resistance in A Shore units is read from an analog dial.
Choosing a squeegee durometer, available from 50-95 Shore A, depends on your substrate, mesh count, and screen tension.
Very soft squeegees (for example, a 55 durometer) are soft enough to conform to varying garment thicknesses or uneven platen surfaces. However, they tend to bend under high squeegee pressure.
Harder squeegees (for example, an 80 durometer) are much less forgiving and will not print an even layer of ink on an uneven surface, such as a textured weave. However, these higher durometers are required to stand up to the high pressure needed to print at high speed or with high-opacity, high-viscosity thick plastisol inks.
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