Fabrics are available in four (4) types of construction groups: BIAXIAL, WARP UNIDIRECTIONAL, WEFT UNIDIRECTIONAL and POLYMER CONCRETE. The first three (3) are conventional type fabrics. However, the polymer concrete group is very open which allows the large aggregate to freely flow through the fabric.
In COFAB® knit products the polyester stitch yarn holds the glass matrix in place while at the same time allowing the strands to move without gaping. This feature is what makes COFAB® conform so well into both inside and outside corners and tight angles. When the fabric is molded on uneven objects, it conforms to mold the shape exceptionally well. Also when formed around sharp external corners, you get no gapping of the fabric.
With COFAB® fabrics you do not get the fall out of small fibers that you do with those that are stitched. Stitched fabrics are basically sewn fabrics, and the needles fracture some of the glass filaments which then fall out. This is especially troublesome in pultrusion operations because these loose fibers tend to clog up the die. Not only does this tend to clog up pultrusion dies or other equipment, it also lowers the strength of the composite.
With COFAB® fabrics you get superior wet-out. The open channel between both the warp and weft ends create natural canals for the resin to flow in (see photograph on MAIN PAGE). This, in addition to the small openings from the front to back, in conjunction with the physical characteristics of the glass we use, is what gives COFAB® its superior wet-out.
COFAB® fabrics are efficiently compatible with all resin systems.