How to Buy: Screen Stretching Devices

March 01, 2004

You've probably noticed that it's the 1,001 details that are important in screen printing. One of the best examples of this is the effect that maintaining consistent screen tension can have on the quality of printing in your shop.

The best way to solve inconsistent screen tension problems is to stretch screens in house. Stretching your own screens gives you enhanced control over production — not only increasing printing consistency and, as a result, quality, but eliminating any stop in production that results from damaged or broken screens.

In addition to consistency benefits, stretching screens in house can also save you anywhere from 10% to 30% of the cost of purchasing pre-stretched screens. Still, many screen printers buy their screens pre-stretched.

While pre-stretched screens are a convenient option for small printers, it makes maintaining consistent tension across all of a shop's screens difficult because the printer has no idea when or to what tension any given screen was stretched. And because screens begin losing tension immediately, they likely have vastly different tensions, which translates to registration problems and slower printing speeds.

But while there's no denying the consistency and quality benefits that stretching your own screens provides, the economic feasibility of a stretcher for your shop largely depends on its size and business volume. And unless you're using more than 50 screens a day, it might not be worth the initial equipment expense or manpower investment. With that in mind, here's a guide to buying screen stretchers.

Stretcher Types

Screen stretchers can be divided into two main groups: manual stretchers, which are either mechanically cranked or manually pulled, and pneumatic stretchers that use compressed air to tighten mesh across a frame.

Manual stretchers range in complexity from basic, inexpensive hand stretchers to larger mechanically cranked stretchers compatible with a wide range of frame sizes. Pneumatic models either use a bar or clamps to attach mesh.

The most important performance differences between manual and pneumatic stretchers are their relative ease and speed of use. Manual stretchers generally require more expertise and training than do pneumatic stretchers and are much slower in terms of production.

Manual hand stretchers, for example, require a user to physically stretch a screen and, at the same time, glue it in place. Conversely, pneumatic systems, which are the easiest and quickest option, require a user to simply drop a frame into place, lock mesh into the bar or clamp and monitor tension as the air compressors do the stretching.

Accessories

Two types of frame glue are in vogue on the market; each has its merits. Cyano acrylade glues dry almost instantly, which is good for someone grappling with a manual stretcher. But they are also thick and leave a considerable amount of adhesive on frame, which translates to more sanding.

The second type is a two-part epoxy that can take anywhere from five to 15 minutes to harden, but it is substantially less expensive than its quick-drying counterpart.

Care and Feeding

All stretchers require some light maintenance, including lubrication and the replacing of fittings and clamps.

Additionally, the level of required maintenance increases with the complexity of the stretchers, with manual stretchers needing the least and pneumatics requiring the most.

The Numbers Game

Just as with difficulty of operation, there is a price hierarchy for the different classes of stretchers, running from a low of manual hand stretchers to a high of pneumatic clamp systems. Generally speaking, manual stretchers cost less than $1,000, with some simple stretchers like the manual handhelds, coming in at about $200. On the other end of the cost spectrum, a printer can expect to pay from $1,500 to $2,000 for a pneumatic clamp system. — L.W.