Wet vs. Dry Carbon Fiber, Revisited

Just a little over three and half years ago we ran a blog post on the differences between dry and wet carbon fiber. Thanks to one intrepid commenter, however, we discovered that while we got most things right, there were some aspects of the analysis that weren’t entirely accurate. Let’s take another look! 

If you’re a car fanatic, you’ve definitely seen this material everywhere from accents to interior features. Outside of cars, carbon fiber is commonly seen in bicycle helmets and pocket knives as well. 

Many people see carbon fiber as a particularly futuristic, 21st century material, but it actually has its origins in the mid-19th century, back when Thomas Edison’s predecessors were trying to find the right material with which to make a lightbulb filament. Since then they’ve become an indispensable material in our post-industrial world.

Now, because carbon fiber is so common in cars these days, it’s important for any detailer to know the difference between the two kinds of carbon fiber, their various properties, and how to properly maintain them. So in this blog, we’ll break down what makes wet carbon fiber wet, what makes dry carbon fiber dry, how they match up, and how to maintain them. Let’s get into it. 

• Wet Carbon Fiber 

In our last blog on the topic, we suggested that wet carbon fiber gets its name from its glossy, “wet” appearance. In fact, the “wet” moniker refers to its manufacturing process, by which the carbon fiber is coated in liquid resin before being vacuum sealed to cure.

Typically, a dry carbon fiber cloth is placed into a mold which has been coated with resin. Then, another layer of resin is coated on top of the cloth. Then the cloth and resin are sealed into a vacuum. The vacuum’s pressure impregnates the resin into the cloth, basically encasing it within the resin and giving it the sturdy structure most people associate with carbon fiber. This process leaves the fiber with a glossy appearance, however this can be altered by using a matte lay-up or sandpapering.  

• Dry Carbon Fiber 

Dry carbon fiber’s name also comes from its manufacturing process. During manufacture, dry carbon fiber has its resin pre-impregnated, that is, literally built into the fiber. Since no resin is being directly applied, the fiber is “dry”.

Pre-impregnated fiber is called “pre-preg” in the carbon fiber industry. The pre-preg fiber is placed in an autoclave to cure at high pressure and heat, which removes impurities and strengthens the material. Because the resin is baked in rather than applied on top, the fiber generally comes out looking flat rather than glossy. However, this look can be altered by applying a glossy layer of gel coat. 

• Comparing The Two

Now that we’ve broken down the definitions of wet and dry carbon fiber, let’s see how they match up in different categories. 

• COST

Wet: Less expensive – production requires less costly equipment

Dry: More expensive – prepreg fiber costs more to produce, and the need for an autoclave also ramps up costs

• STRENGTH

Wet: Weaker – the wet process has a greater potential for air bubbles and wavy fiber weaves, which reduces strength

Dry: Stronger – the autoclave process eliminates air bubbles and other impurities, strengthening it significantly

• WEIGHT

Wet: Heavier – applying resin rather than pre-impregnating it results in a greater weight 

Dry: Lighter – pre-preg fiber weighs up to 70% less

• QUALITY

Wet: Lower – it’s less strong, heavier

Dry: Higher – it’s much stronger and much lighter

• MAINTENANCE

Wet: Requires proper maintenance to keep its appearance

Dry: Requires proper maintenance to keep its appearance

Originally posted in drbeasleys.com