Before flexible faces, large signs were built with rigid plastic faces, and the landscape was littered with broken plastic with every big windstorm. One of the very first applications of Panaflex, in fact, were for retrofitting existing plastic signs, especially high rise signs, and ABC Extrusions were the first to design retrofit parts for Panaflex with our Retro Saddle, Flat Retainer and Tensioning hardware. (fig. 1) This eliminated face blowouts when the faces were installed according to 3M's and ABC' instructions.

However, they soon found that many of these angle iron and sheet metal sign frames were not strong enough to withstand the combined face tension and wind loads. Unlike plastic faces, that broke and fell out, thereby relieving the wind load on the sign, flexible faces transferred the entire load to the frame. Too often, the frame would deform, loosening the face, and in some extreme cases the entire sign blew down because the foundation was inadequate.

3M then developed and published their engineering criteria to which any angle iron frame had to be built, or modified, before they would guarantee the face against blowout. Modifying these signs in the air was difficult, and they often had to be removed to add the struts and knee braces, then reinstalled. In most cases, this was cost-prohibitive.