Introduction: Carbon Fiber Motorcycle Rally Fairing

About: Matthieu Libeert, Born 24th January 1990. Fascinated by Design, Prototyping, Composites, Digital Arts and Video editing.

In the following 4 Steps you'll find video's explaining the entire process to shape and make your own motorcycle rally front fender in Carbon Fiber.

I do know and understand that not everyone will be able to make this due to some equipment you'll need but at least I think the process might interest you or inspire you.

In the following 4 Steps you'll find:

1. Shaping the rally fairing in foam and reinforcement with fiberglass + Adding the finishing coat for the plug.

2. Finishing the pre-mould by sanding and adding flanges to make it mould-ready

3. Making a strong durable mould

4. Making the carbonfiber front fairing using epoxy and resin infusion technique.

This is just one of many projects I make on my YouTube-channel: If you are interested in more of my video's make sure to check my YouTube-Channel and subscribe ;)

Step 1: Shaping and Preparing the Mould-plug

So this is a basic step. The original front fairing was adjusted by cutting the original front fairing and adding polyurethane blocks. These are low density foam blocks that can easily be shaped by using knifes a band saw or sanding papers of any grid. This is a step that is totally up to you, at which you feel most at ease with. Once everything is shapes like you want you add some Polyester resin to reinforce the foam and remove the porosity of the foam. Once cured you can proceed to the next step of adding bondo/filler to smoothen the surface. Most important step here is to keep the symmetry. Once happy you can finish with a topcoat. I've used a pattern coat from Easy Composites: to finish it. It is an easy to sand polyester top coat that can be applied by brush or spray gun like I did in the video. You add mix the amount you think you'll need with 2% of MEKP hardener and some acetone to thin it down. Once sprayed you let it cure and can proceed with the sanding. Keep in mind that this layer wont fill mayor cracks or dents, this is a finishing coat to remove small pits and pinholes. The scratchmarks will be removed as well that were added by the high grid sanding paper you've sanded with.

Step 2: Sanding the Plug to Good Finish

So the pattern was applied and left to cure over night.

now you can start sanding it to a good finish. Keep in mind that the finish of your mouldplug will be completely identical to the finish you'll have on your mould, so take that extra time to finish it well!

Sanding starts with a grid between 120-200 and work your way up to 600 or more. If needed fill some dents with a polyester 2k bondo. If you've sanded most of the pattern coat, it's sometimes better to re-coat it once again.

The flanges were then added by using some hot glue to create a barrier all the way around part with wooden pieces. On top of these pieces you can then add a flange by using some flute board.

Next very important step is to add release agent. I'm using the Chemical release agent from Easycomposites.

Once all of this is done you can proceed to the mouldmaking

Step 3: Making the Mould

So now that the mouldplug is ready with the flanges and release agent applied you can start with the mouldmaking. For this step I'm using the uni-mould tooling resin from Easy Composites. This will create stable moulds that won't warp or shrink after curing. You could also use a regular gelcoat and fiberglass with polyester but make sure not to add to much layers at once, this will cause shrinkage.

The first layer is the gelcoat. In my case this is a black gelcoat but if you look online you could find it in any colour you want. The colour doesn't really matter. Let it cure to a tacky state before applying the next layer.

The second layer is the coupling coat. This coupling coat will create a nice bond between the gelcoat and the layers of tooling resin coming on top. You use the coupling coat with a 100 gram square meter chopped strands fiberglass. Make sure you apply it well and have no airbubbles under your fiberglass. These would otherwise create a weak spot in your mould. Let it cure to a tacky state again before going to the last step.

Ther third and last layer is the tooling resin. This is a filled polyester resin. You apply it with 3-4 layers of fiberglass chopped strands, making a strong mould. Make sure you have everything evenly saturated for a nice and thick mould. Once finished clean your tools and let it cure for a few days at 20°C ideally. You'll see that the resin changed colour from brown to vanilla white.

Once cured it's just a matter of demoulding and finishing the mould before the next step. If you want you can re-sand the mould to a better finish using sanding paper from 400-1200 or more till a high gloss. The flanges were cut as well with an angular grinds to remove all sharp edges. Apply release agent and you are ready for the last step.

Step 4: Making the Carbon Fiber Part

So the mould is ready and we can now proceed to the most important and probably most difficult part.

In this step we'll use resin infusion as the technique where you infuse your epoxy resin under vacuum. Keep in mind that once you have the mould you could also use other production techniques with different materials like chopped fiberglass and polyester (like we've made the mould) or use fiberglass instead of carbonfiber.

The lay up here is made from carbonfiber for it's stiffness and kevlar/aramid for its good properties against impact (in case of a crash)

For the technique we are going to use you lay all the fibers dry in the mould. After that you add a layer of peelply to be able to remove the infusionmesh and vacuumbag that is on top. This leaves you a nicely compacted carbon fiber part thanks to the vacuum creating a pressure compacting all the fibers tightly against each other.

Once you have the part under vacuum. Meaning you have a tube to let the resin in on one side and a vacuum tube on the other you are ready to mix the resin. The resin used is IN2 infusion resin from Easy Composites. Make sure you have an infusion resin as the viscocity of the resin is way lower than regular laminating resin. This will help it flow better under the vacuum bag. Once all the epoxy resin went through the laminate you can clamp down both tubes and let it cure under vacuum for over 48h ideally at 25°C. Once cured you can remove the peelply and infusion mesh leaving you a nice carbon fiber part. Followed by trimming, some extra sanding and an extra layer of clearcoat (matte finish in our case) You are done and you can fit your own made rally fender on your motorcycle.

Keep in mind that this is a technique that could work for any part you would like to make with carbonfiber. So you are not limited to motercycle parts but you could also make car-parts and more!

Step 5: Enjoy Your Ride!

Be safe on the road and enjoy your ride!

In case you have some more questions I will be happy to answer them in the comment section below!

Matthieu Libeert

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