Getting Clever With Carbon Fiber

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Now that all that stuff is at hand get started by cutting all the materials to size.  Lay out your core material and then cut the carbon cloth to match it.  For complex shapes one can use a bit of spray adhesive to help set the cloth into the mold. 

Once that is done mix up the correct amount of resin (same as the weight of the cloth) and, using a cardboard squeegee gently work the resin into the cloth.  If you are working with a very complex mold that can't be accessed with a squeegee you can impregnate the cloth first and then lay it into the mold.  Once the cloth is wet, get a cut of that perforated bagging film and lay it over the part.  The idea with this stuff is to press the cloth into the mold but allow air and excess resign to escape out the little holes.  That brings us to the next layer and that's the breather fabric.  This stuff does two things:  One is to allow the air to escape the vacuum bag as it prevents any air pockets from forming.  Two, is that is soaks up excess resin that gets squeezed through the perforated film by the extreme pressure of the vacuum bag.  The perforations will allow about 20% of the resin to come through and this means that you will get a nice thin part with a minimum of excess resin. 

After the materials are laid in the mold and everything is ready it's time to build the bag itself.  One just needs to enclose the part and mold with in the bagging film and then use the sticky butyl tape to adhere to bag together and make it airtight. 

 For big, flat, molds like the one I am using here you can just stick the bagging film right to the mold and be done with it.  The pictures above show the black butyl rope sticking the bag to the mold.  The last step is to stick the vacuum hose into the bag and start the pump.  I used a suction cup with the middle cut out as a hose to bag adaptor.  Add a bit of butyl to seal it and all is airtight.  Once the vacuum is started it's easy to see how the excess resin is getting pulled into the breather cloth (third picture above).  Now it's just a matter of waiting for the resin to cure and then peeling off the bag to reveal your finished part. 

So, how well does adding carbon to a thin core material work?  Here are some stats.  We started out with a 20.39 oz piece of luan paneling and ended up with a 25.31 oz final part after adding two layers of carbon fiber.  5 more ounces is not much over a 2 x 4 foot part. 

With the panel all cured and ready, let's do a very informal flex test.  First we look at the panel without any reinforcement on it.  Two bottles of wine and it's about to bend in half. 

Now, check out the same panel after the carbon has been added!  Wow, two bottles of wine weight and it's barely flexing at all!  Grabbing this stuff and flexing it in your hands is really when you realize its terrific strength to weight ratio.  Space age material with backyard prices!!  Cut to shape with a jigsaw and super light, strong, and cheap, dashboards, splitters, under-trays, or whatever, are ready to go for your home grown project machine.  Don't be precious about this stuff.  Experiment and try new things to make parts that are available only to you!