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Solving the Mystery of Screen-Tension Loss

(March 1999) posted on Wed Dec 15, 1999

Rosson offers advice on tracking your tension culprit.

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Some printers argue in favor of using staples to attach pretensioned mesh to a wood frame. But staples are not cheaper than suitable adhesives--not when you consider time, damaged fabric, frame damage, and the tedious job of pulling all those staples when renewing fabric. If your screen maker uses staples, do him or her a favor--hide the staple gun and forbid the purchase of a new one. Staples are good for attaching garage sale signs to trees and poles. They are not suitable for making printing screens.

With both wood and rigid metal frames, you can attach screen fabric reliably using adhesives designed specifically for screenmaking. Cyano acrylate (CA) types are the most popular and are sold under brand names such as Frame Fast, Pacer, Mesh Bond, etc. Other available adhesives include epoxy, urethane, and polyester. CA types are much faster than these alternatives, but they are rather expensive.

Most screen makers use too much adhesive by covering the whole frame surface. A 1/2-in.-wide strip along the outer edge of the frame is entirely adequate. The frame must be thoroughly dry and thoroughly clean when adhering fabric. Correctly adhered fabric will not slip.

Retensionable frames have a fabric capturing system that usually consists of some sort of plastic strip or rod that locks the mesh into grooves on each side of the frame. The frames are characteristically aluminum, which is not affected by moisture or heat. On rare occasions, the capturing strip will allow the fabric to slip. This is most likely to occur when you use a fine fabric, such as a 390-thread/in. mesh, but almost never happens with lower mesh counts of 110, 155, or 230 thread/in.

Deflection: As mentioned previously, under the load imposed by tensioned fabrics, all frame types will deflect or bend inward to some degree. However, this deflection is only debilitating if it occurs after the tensioned fabric is attached to the frame. As a general rule, you can calculate the acceptable deflection for the longest sidebar on your frame as 0.3% of the length of the longest sidebar.


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