Easy to Extrude Curved Carbon Rod

This is a technique I came up with about 10 or 12 years ago that I use a lot on different boats. You can produce any diameter rod from .125" up to probably .5" by hand-others could be done but woud require more force and this covers a lot of applications–any time you could benefit from a curved carbon rod-your imagination is the limit .
First you have to build a wooden jig to support the diameter silcone tube you will use. I try to use 75 durometer silicone with a .125" wall. The jig is built to the shape you want the final rod to have.
Use 6K tow(available from Aircraft Spruce-enough to last a long,long time costs $58) . If you look you might find smaller quantities of 6k tow available
Once you have the diameter and design decided upon cut a length of silicone tube the same length ; then take a piece of wire a little over twice the length of the silicone tube and bend it in the middle . Then bend the free ends of the wire so that they can be pushed easily thru the silicone tube.
Next, put two nails in a piece of board a little longer than the piece you are going to make and cut off the heads-leave the nail sticking up about 1". Then wrap 45 strands of 6k tow around the nails per .25" of diameter of the finished piece.Tie the loose ends together. Use this exact fiber density at any diameter and you’ll produce a void free extrusion.
Then pass one end of the wire thru the carbon strands(near one of the nails you have wrapped around the nails and pull the wire until the center of tke wire is at the nail-be carefull to pass the wire thru near the nail so that it catches all the fibers on one side of the nail. Mix up your epoxy resin and use the wire to pull the strands off the nails; coat the strands thoroughly -DO NOT SQUEEGEE. Then feed the wire ends thru the silicone tube and grab them with a pair of vice grips and pull. The wet carbon will slowly pull thru the silicone tube. When you have a little hanging out of both ends of the silicone tube cut it off and place the tube in the waxed jig you built. Waxing is just a precaution since a very small amount of resin will come out each end(couple of drops) and if you were carefull you didn’t get any resin on the outside of the silicone tube.
The next morning use a razor knife and cut off the silicone tubing and you will have a beautifull extruded carbon rod extremely stiff and extremely light for its strength.

Doug Lord
–High Technology Sailing/Racing

We used to make carbon tubes on a mandrel. A slight taper is all that is required to allow the tube to be pulled off the end.

After machining the slight taper, you could bend the mandrel to form an arc of a circle and then you would be able to pull the tube off the mandrel when done.

We used shrink wrap tape to sqeeze the extra resin out of the tubes after layup to get bare bones weight.

  • Will

Will Gorgen

This technique allows 90 degree bends and all kinds of odd shapes; it is howver limited to making only solid rods…

Doug Lord
–High Technology Sailing/Racing