FAQs

Carbon Fiber vs Kevlar vs Fiberglass

Are all fabrics the same?

But why the price tag?

More Details

There is often confusion and misinformation on the various materials used in the manufacture of composite body panels. The three most common materials are Fiberglass (which can be either S Glass or E Glass), Kevlar and of course, Carbon Fiber. Each have their own advantages and disadvantages.

To understand the differences we first need to clarify a few technical terms. We will start with strength, stiffness and toughness. Here is a video that goes into much more detail explaining pros and cons of the various materials: Carbon Fiber vs Kevlar vs Fiberglass - Which one is right for YOU?

• Strength is the ability of a material to resist a load, either in tension or compression.

• Stiffness is the ability of a material to resist bending.

• In simple terms Toughness is defined by a materials ability to stretch before it breaks.

The above are very important in proper material selection. For example, Carbon Fiber has strength in both tension and compression but Kevlar, while it has tensile strength is very weak in compression. In addition, Carbon Fiber is roughly 2X stiffer than Kevlar. In a panel that can see loads in multiple directions and needs to resist bending forces, such as a roof panel or hood, carbon fiber is the best choice for optimal strength and stiffness.

In contrast, if a panel requires abrasion resistance and toughness, such as a skid plate or front splitter, Kevlar and/or S Glass have better properties and should be considered as either the primary material or in combination with carbon fiber. When materials are combined the end result will often be referred to as a composite hybrid .

There are two basic types of materials used in the manufacture automotive composite parts the outer or cosmetic layer and, if necessary the structural or support layer.

If you see terms such as 3k or 6k that describes the number of strands. Carbon fiber starts as very, very thin strands of fiber that are finer than a human hair. These strands are twisted together like yarn (called a tow) and woven into carbon fiber fabric which typically comes in 3k, 6k and 12k weights. A 3k fabric has 3,000 strands of carbon in each tow while a heavier weight 6k fabric has 6,000 strands per tow.

Weave is critical for two reasons – appearance and functionality. Each weave looks very different and sometimes people prefer the look of a certain weave for a specific application. Also, weave impacts product strength. A unidirectional weave creates a carbon fiber sheet that’s very strong in the direction of the fibers, but weak in the opposite direction. Plain and twill weaves, on the other hand, have more uniform strength since they’re strongest at the points where the fibers cross in either direction.

• Cosmetic layers

The primary purpose of the outer is cosmetic. Often the weave, pattern or color drives this choice. A quality dense weave holds its shape well and provides symmetry across the entire surface. You will see terms such as 2x2 or 3x3 twill , this describes the weave and pattern.

• Structural layers

In most applications such as a roof panel we use multiple layers of 6k high modulus carbon to deliver strength and stiffness for the body panels. If the part is in an area where abrasion or impact resistance is a critical design consideration the introduction of Kevlar or other materials is used.

When it comes to the cost of composite panels it is driven by the type and quality of materials and the cost of labor associated to manufacture the products. The labor cost is simple to address, have the parts manufactured in a location where they pay people pennies on the dollar.

When it comes to materials it is often more difficult to see. Quality base materials a key to strength and durability. We use only the highest quality name brand fabrics and resins in all of our products and refuse to cut corners. If you have any questions on the details don’t hesitate to reach out.

If various common questions arise we will continue to add details here.

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