Dry carbon - Lost in translation

In this article my goal is to clear up any confusion around the term “dry carbon fiber”. I rarely see it used correctly. So, by sharing some background information, my hope is to lay “dry carbon” to rest and stop the misrepresentation of some carbon fiber parts.

With todays social platforms and unregulated and unfiltered outlets, there’s so much misinformation in pretty much every industry. Sometimes the only way to find out what’s real or not is to go to the source or learn by trial and error.

Remember the broken telephone game? The one where someone whispers a phrase in someone’s ear, and they pass it on to the next person? By the time it gets to the last person in the circle, it’s a totally different phrase with a totally different meaning. Think of information on the internet the same way. One person misinterprets the information or meaning and passes it around like its fact. This is dangerous because anyone can position them self as an expert and not really know fact from fiction. And when you add different languages, terms and cultures to the mix, things get even trickier.  

In any high-performance field, whether it is motorsports or space exploration, mistakes happen when engineers and technicians don’t communicate correctly. Standards are put into place to ensure a part is manufactured in a repeatable way which will result in specified physical characteristics. The most efficient manufacturing plants have refined workflows to save on time and mistakes.

The carbon fiber industry, being used in high-performing applications like motorsport, relies on several documented procedures and standards to ensure a part is manufactured correctly. This leads me to the point of this article — to help put an end to ‘bad descriptions’ and ‘slang’ when selling carbon fiber parts. A customer should also know what they’re paying for. And with carbon fiber, there are many ways to make a part that still falls under the ‘carbon fiber’ umbrella, but may not actually be what the customer expects it to be.  

“Dry” carbon doesn’t mean a satin finish

What’s the first thing that comes to mind when you hear the term “dry carbon”? I’ve seen and heard this term used many times to describe a carbon fiber part with a satin or flat surface finish — referring to the clear coat that’s applied on top of the part.

In the composite manufacturing industry, this is not what “dry” carbon means.  It’s actually common for major carbon fiber manufacturers to outsource the coating stage to specialized auto body and paint shops. This stage is considered the final stage of a composite-part workflow. The most correct use of the term “dry” carbon actually comes in play right at the beginning of the work flow, when the engineer plans how to manufacture the component, even down to the specification of the mould.

What does “dry carbon fiber” really mean?

First, let’s agree that different companies and countries use different terms for their processes and materials. In manufacturing environments, there are lots of non-technical ‘slang’ terms used to save time in relaying information. In carbon fiber manufacturing, for example, we use handmade tools we call “dibbers” to help manipulate material onto the moulds. I’ve been using this tool for many years before I was in the professional composites field, but only heard of the term “dibber” when I entered the workplace. Another common term, the “crack-out”. This refers to de-moulding a part after it has been cured. But it’s in your best interest to not actually crack the part.

In my experience, the term “dry carbon” is rarely used in composite environments. But where it may be heard is to describe pre-impregnated carbon fiber, “pre-preg” for short. Pre-preg carbon fiber is manufactured by taking carbon fiber fabric and combining it with a high-temperature epoxy resin. At room and working temperature, this resin is ‘dry’ to the touch, which gives light to the reference. This combination makes it much easier to manipulate, cut and form complex carbon fiber layups — and less messy too. Many of todays supercars are manufactured using pre-preg carbon fiber. This is a more expensive way to create carbon fiber parts, but it’s also the quickest and easiest. Complex parts and structures, that would be next to impossible to make with traditional wet-lay and resin transfer methods, are easily constructed with pre-preg methods. Parts made this way require an oven or autoclave to elevate the temperature to liquify the resin, which will then undergo a chemical reaction, that’s accelerated by heat to cure into a solid. The pre-preg with autoclave method produces the strongest possible parts, with the least amount of material waste.

If there’s dry carbon fiber is there also wet carbon fiber?

Yes, and we don’t see this term used as much. Just as we mistakenly associate dry carbon with a satin finish, we’d mistakenly associate wet carbon with a glossy finish. Anyone who’s worked with all carbon fiber manufacturing methods will tell you that wet-lay carbon fiber is not fun. It’s a very messy process. Instead of working with an easy-forming, easy-cutting and conveniently-tacky sheet of carbon fiber, you’re dealing with a nightmare of fraying strands and dripping resin. But for hobbyists and DIYers, the wet-lay is the easy way, and theoretically the cheapest. I say theoretically because by the time you have made a part you are happy with; you would have probably gone through a few iterations of moulds and scrapped parts.

The wet-lay method uses carbon fiber fabric that’s ‘dry’. Referring to the fabric sans resin. This is exactly how the term dry carbon can get confusing and misused. It shouldn’t be used at all. Instead, let’s use the correct technical terms:

Carbon fiber fabric – carbon fiber sans resin, used in wet-lay and resin transfer applications

Pre-preg – Carbon fiber fabric that has been impregnated with resin before you purchase it. Requires a vacuum bag and oven or autoclave to cure.

Satin finish – This is the reference to the sheen or reflectivity of a surface, clear coated or bare.

And remove these terms from your carbon fiber library completely, there is no need for them:

- Wet carbon fiber

- Dry carbon fiber

- Wet look

- Dry look

So, there we have it, if resellers and manufacturers stick to a global standard, there would be much less confusion, but since that is very hard to do, it is best to educate yourself, especially if you are planning on spending money on something.

As much as slang can be useful in an industry, it is critical that everyone is on the same page. This can be something that can be utilized in a small workplace (assuming everyone gets the memo) but does not transfer well to the vast online information database, which at the end of the day, leaves it to you to determine whether the information you are getting is good or bad.

As a business owner who is passionate about creating high-quality, well-designed carbon fiber components, it’s in my best interest to share my years of hard work and trial and error with all of you. I’ve spent years researching and working on my craft. I hope this article, and any other article from the STEVS site, helps you can make informed decisions when making your next carbon fiber purchase. There is so more to carbon fiber than meets the eye; performance and longevity is largely dependant on processes and choice of materials. Always get as much information as you can before making any sort of investment. But when carbon fiber is done right, by a company that has the drive, passion and know-how, it’s a thing of beauty.

Cheers and stay safe during these challenging times,

Matt Ristevski