Restoring carbon fiber parts

So your fancy and expensive carbon fiber parts have scratches and scuffs and you don’t know what to do? Don’t worry, with a little sweat equity you can have them looking like new. Also be sure to check out my post on repairing damaged carbon fiber.

Recently, a friend of mine got a deal on carbon fiber interior trim pieces for his car. A part of why it was such a deal was that, unfortunately, the pieces have been sitting around for quite some time and were improperly stored. This put minor blemishes such as surface scratches and scuffs onto the parts so he asked me if I could remove them and clean the pieces up.

I have seen some detailers write about polishing CF with double action buffers using Megquires 105 and 205 compounds. Although this does work, these compounds were designed to work on car paint and clear coats which are much softer than an epoxy or polyester resin – which is what is found on CF parts. You can expect those compounds to work very slowly and to be only effective (within a reasonable time frame) on minor swirl marks.

The parts that were brought to me required a little more attention since they had scratches which would catch your nail. It was obvious that the Mequires products were not going to work for this, so I took it to the next level: a real buffing wheel mounted on my die grinder with proper buffing compound in brick form.

For this project I used a ‘Loose section’ 4″ buffing wheel from the Eastwood Company, but any soft/mild wheel will work. I also tried Eastwood’s string buffing wheel which I couldn’t find anywhere else. The string buff is made for a high horsepower bench top buffer, but I was able to adapt it to my die grinder. The string buff is a larger 6″ diameter and my die grinder just didn’t have the power to turn it as fast as I wanted. I found the string buff to be very mild and used it for my finishing pass.

For compounds, I used Eastwood’s blue plastic compound, Kocour plastic compound, and Meguires Ultimate Compound for finishing. I found that Eastwood’s plastic compound to be extremely mild and worked very slowly. I retired use of it early on in favor of the Kocour product which is a little more aggressive and applied to the wheel easier.

It also must be noted that you cannot use a buffer of this magnitude inside the car. The amount of dust and debris created during the buffing process would surly ruin the rest of the interior. You can see how dirty I became during the process in the first photo. Luckily, all of the pieces that were brought to me where not installed. This also gave me easy access to any otherwise difficult to reach places.

The buffing process itself is pretty straightforward. Make sure the piece is free of dirt or any other contamination. The same goes for the buffing wheel. If you accidentally set the wheel in a dirty place, its over – The wheel has to be discarded and replaced. Apply the buffing compound to the wheel by spinning the wheel into the compound. Then finally start buffing the piece. Make sure not to stay in one spot for very long because it is possible to burn the piece. Also, do not spin the wheel into an edge of the piece your buffing; doing this can launch the piece across the room. Turn the piece or the buffer around so that the wheel is spinning towards the edge when approaching them.

Carbon fiber show pieces are actually pretty easy to buff since the top coats are thick and the resins so hard – unlike clear coat on paint. Heavy scratches and scuffs can be removed without fear of going into the fiber underneath. This is not to say it’s impossible; you would have to be careful buffing a piece that’s already been buffed out in the past.

After all your buffing is complete and the scratches removed, you will notice that some of the compound is sticking to the piece and looks like a haze. This is where finishing with a fresh buff and a Meguires compound, such as their Ultimate Compound, comes in handy. I like the Ultimate Compound since its very aggressive initially and has diminishing crystals which break down into finer and finer abrasive which leaves a perfect finish. The Mequires product also acts like a cleaner that removes the left over haze. I used the string buff for this which worked well. I think it would work even better if I had more power to turn it.

After comparing the pieces I polished to some of the other factory pieces, the final result might actually bet better than what comes from the factory. This piece is the center console to a Murcielago.


Food for thought:

The smaller the piece your buffing is, the easier it is to launch. This is because edges of small parts are always really close to the wheel. It simply takes rotating the piece a little of the wrong way, or working to close to the edge for the buff to grab it and embed it into your ceiling.

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1 Comment to "Restoring carbon fiber parts"

  1. dame frank's Gravatar dame frank
    August 18, 2014 - 7:22 pm | Permalink

    im a builder of multirotors and find that my frames after im done have small light scratches here and there anyway you can help me out and lead me in the right direction to make my frame plates look new?? thx man

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