Carbon Fiber: The Quick How to Guide

I’ve been working on a carbon fiber project recently, and I wanted to share with all of you a few of the details about the whole processs of making a custom carbon fiber pieces.  It’s not too difficult, but does require some patience and work.

  This first photo shows the male and female molds I made in order to form my carbon pieces when pressed together.  The male mold (green) I made by milling out a pocket in a 2×4 board, filling with bondo, and laying my desired shape (in this case my hand) into the bondo till it was reasonably firm.  I then cut the hand imprint out of the 2.4 and covered it in green tape.

The female mold that’s under the green male mold was made by milling out another pocket in a block of wood, filling the pocket with bondo, and then pressing the male mold (green) into the female mold until the bondo was mostly firm.  Now that I have both the male and female molds finished, I can cut my carbon fiber fabric pieces to close to my desired shape, and then start the next process.

Here you can see one of the carbon fiber pieces I cut out that is laying on top of the male mold.  Carbon fiber fabric is just like any other fabric when you first hold it in your hand, but it’s potential once resin and hardener is applied is unique.  In this piece I used six layers of carbon fiber, so I needed six individual pieces cut out to lay on top of each other (4 are pictured).  The key when you cut these pieces is, with each layer you plan on laying down, make sure the carbon weave is running in a different direction than the previous piece.  As I cut these pieces, i basically had a center point that i rotated around as I cut each piece.  That ends up with six pieces, each with a different weave direction when laid on top of each other.

I now need to coat the female and male mold in turtle wax, so that after I press the carbon fiber into the male and female mold, the carbon fiber will not stick to the mold.

You can simply use your finger to coat each mold.  Just make sure you use a flat-blade screwdriver or something with a fine edge so that you can get wax down into any tight corners or edges that are inaccessible to you fingertips.

  Next, the resin needs to measured out and the hardener added to the resin.  This is simply a photo of my digital scale while I’m weighing out the resin correctly.

  Now comes the part that can get a little messy.  The resin needs to be brushed onto each carbon fiber piece very well.  The resin also needs to be pressed into the fabric extremely well, which can be accomplished by using a rubber brayer or household rolling pin.  The carbon fabric will want to stretch, so you constantly have to reshape each piece as you roll the resin into the fabric.  This resin was pretty fast drying, so I had to move quickly.  Each side needs to be coated well…wear gloves and get to it!

This next photo shows some of the resin filled carbon fiber pieces laying in the female mold.  There were 6 layers of fabric in all that I used in order to create a piece with the right stiffness I was going for.  Use your flat blade screwdriver again here to press the edges of the fabric down into the bottom edges of the female mold.  Basically, you  want to try to compress the fabric slightly into the mold before pressing the male mold into the female mold.  Don’t worry if it doesn’t look pretty right now, it will once it’s finished.

After you have laid all your desired pieces into your female mold, you can press your male mold into the female mold and then stick the whole contraption into a vice in order to generate some good pressure for about an hour of so in this case.  I also cut a few small channels into the female mold in order for the excess resin to drain out when I pressed the molds together.  These channels do not need to be big at all.  A channel the diameter of a small sewing needle is plenty.  Just make sure to evenly distribute your channels around the perimeter when you cut them.  You can see the resin dripping out of the mold channels I cut, and onto the blue paper towel.

Once you take the mold out of the vice, remove the male mold and let the carbon fiber air dry in the female mold for another hour or so.  It all depends on the drying time of your resin.  Some resin is fast drying, other types are very slow drying.  Each has it’s own unique use.  Once it’s all dry, pop your carbon fiber piece out, trim off any excess unwanted carbon shreds, and your finished.

Here is my finished carbon fiber piece that I will use for my experimental project.  I had originally completed this whole process using only 4 layers of carbon fiber, and after I took the piece out of the mold, it was not stiff enough, so I re-did the whole process this time using 6 pieces.

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~ by johncobbresearch on March 21, 2012.

One Response to “Carbon Fiber: The Quick How to Guide”

  1. looks like fun – so where does one buy small quantities of carbon fibre cloth and resins to experiment with?

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