Kevlar is a synthetic composite fabric with high tensile strength, high modulus and a characteristic gold color. Its relatively light weight and superior strength make it ideal for kayaks, canoes, surfboards, racing shells and snowboards. It's also used to make cut-proof gloves, bulletproof vests, motorsports helmets and other types of protective gear.
The advantages of Kevlar cloth are that it has a high strength-to-weight ratio, that is, minimal weight and high tensile strength - it's five times stronger than steel. Kevlar is also dimensionally stable, has low elongation, low electrical connectivity, won't expand or melt under high heat, won't become brittle when exposed to extreme cold, it's impact resistant, highly abrasion resistant, chemical resistant, flame resistant, and self-extinguishing. The disadvantages of Kevlar are that it has a poor ability to handle compression, it's difficult to cut, sand or machine, has poor UV resistance, and it's expensive.
The difference between Kevlar 29 vs Kevlar 49 is that Kevlar 29 is ballistics and industrial grade, and is used in bulletproof clothing, helmets, vehicular armoring, asbestos replacement and other applications requiring a higher tensile strength. Kevlar 49 is composite grade, used for composite reinforcement in Kevlar cloth boat building applications including canoes, kayaks, racing shells and more.
Kevlar 49 fabric is used specifically for composite reinforcement. Its high strength, light weight, and abrasion resistance make it ideal for building boats, kayaks, canoes and racing shells. It's also used in the aviation industry for aircraft parts, for race car parts in the automotive industry, and in other applications such as wind turbines, ropes and cables.
Yes, compared to fiberglass, Kevlar is stronger and has better resistance to impacts, penetration, and tearing. Kevlar is difficult to cut, sand or machine, therefore, fiberglass is commonly used as a final layer over Kevlar, or fiberglass is used to repair damaged Kevlar.
When used in composites, Kevlar and carbon fiber are both very light in weight, but Kevlar is stronger, more abrasion resistant, and more impact resistant than carbon fiber. Carbon fiber provides greater rigidity than Kevlar, with even lower stretch, and one of the highest strength-to-weight values of any material.
Twill weave Kevlar fabric has a distinctive diagonal pattern, while plain weave Kevlar has a small checkerboard pattern. Twill weave Kevlar fabric and tape is better for contours because it drapes more easily than plain weave Kevlar. Twill weave Kevlar cloth fabric also wets out a little more easily because it is not woven as tightly as plain weave Kevlar.
Kevlar cloth and fabric tape can be wet out with epoxy resins, vinyl ester resins, or polyester resins to create laminates that are rigid and strong. Note that though polyester is the most affordable resin to use, it doesn't optimize Kevlar's tensile strength and overall stiffness, once cured.