Short cut straight fibers are valuable when used as a clay mix additive (.1-.5%) to greatly increase green strength and drying performance. Fiber is typically used in heavy clay products, such as refractories, where considerable internal stresses are developed during drying. These fibers burn out during firing and have little or no impact on the strength of the fired product.
One problem with the use of fiber additives in clay bodies is that it becomes difficult to cut the plastic material with a wire or knife because the fiber wraps around the leading edge in an increasingly thicker layer, as it is pulled through the clay. In addition, fiber additions are not suitable for items that will need to be trimmed in the leather hard state.
It can be difficult to disperse the clumped fibers evenly throughout a clay mix. One solution is to disperse them in very hot water first then add this to the clay mix.
Hercules company produces a wide variety of fiber products in different colors, lengths and densities for use in filtration, asphalt, concrete, etc. Those of most interest to the clay industry are:
Product Color Length Application
2.2 Den T-153 White 5mm, 10mm Wet Clay
3.0 Den T-153 White 3mm, 5mm, 10mm, 3/4" Wet Clay
4.0 Den T-157 Gray 10mm Asphalt
15.0 Den T-157 White 10mm Asphalt
3.0 Den T-158 White 3/4" Concrete
15.0 Den T-158 White 3/4", 1 1/2" Concrete
3169 Holcomb Bridge Road
Norcross, GA 30071-1394
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