Project CF Intake (...continued)

The plug was waxed with carnauba waxes of many kinds, then some touch up synthetic wax. This would supposedly make it easier to split the CF part off the mold once the resin cured.

Meanwhile, this showed up:

This is a carbon fiber sleeve made by a company called Soller Composites. It is nothing but axially-woven 12K aerospace-quality carbon fiber, woven in perpendicular with tiny little rubber strands. The result is a carbon fiber tube capable of stretching to about 3 times the original diameter. Once it is over a mold, you can pull the ends away from each other to tighten up the spaces between fibers, reducing the amount of resin used to only the necessary. Soller Composites is one of the only 2 companies in the planet with the machinery capable to weave carbon fiber axially, the other one being Toyota, which uses axial CF tubes on the Lexus LFA's A-pillars. Neat stuff!

Ended up paying just over $18 shipped for 2 ft. of the stuff, more then enough for my barely foot-long turd shaped intake.

With one half of the composite raw materials in hand, it was time to chose the resin. Structural Epoxy resin is prohibitively expensive at over $400/gallon, so that was out. I decided to go with plain-old polyester resin for fiberglass applications. Not as flexible as Epoxy, but it hardens faster and more solid, while not going cloudy when exposed to UV rays like Epoxy does. Got about a quart of the stuff from Bondo for about $14 bucks.

Hung the waxed plug (that sounds durrrrty...) on some wire I had around, pulled the ends of the carbon fiber tightly and away from each other, and taped them down with some tape to keep them tight. Soaked the fibers carefully with the polyester, then added a second layer on top of the first one.

With the help of a heat lamp, things were done in less then an hour.

8 hours after, everything hardened nicely (that also sounds durrrrty!) It was time to use a cutting bit to cut the carbon fiber out of the mold.

After an hour of struggling:

Note how some of the Bondo body filler got stuck to the inner CF. Whatever, I took most of it out, and what's stuck is essentially stuck there permanently.

I had to add an extra layer of resin on the inside since the fibers were pretty much try. The semi-final result, trimmed and cleaned up:

I used some Epoxy 2-part glue to glue the halves together rather then just polyester. I figure it would make things a bit more flexible in case the gaps there decide to create stress fractures.

Now on to a test fit:

 The intake was sanded down to remove some imperfections. I added more resin on all sides to take care of any dry spots and permanently seal the gaps caused by the mold splitting.

 The top fit is almost perfect. pretty happy with it. A standard (cut) 3 inch coupler would work fine.

Not very happy about the bottom fit, major design fault. Because of this I had to be rather creative regarding couplers. I couldn't get away from making my own custom couplers, something maybe like these couplers made by some DSM dudes, but I imagined that something simpler could work, especially since my couplers will not make up the entire intake tract and need to be more flexible then structural:

-Make a little belt with electrical tape on the male sides of the intake.
-Use some duct tape to form the couplers around that belt. Duct tape is infused with fibers, so it should be structurally sound much like fiberglass-infused silicone couplers.
-Apply some black RTV silicone on top of the duct tape.
-Once the intake and couplers are in place, use some self-fusing silicone tape tightly around the couplers to finish up the job. The tape should fuse with the RTV turning the whole thing into a nice coupler setup.

We'll see how that goes, but so far so good. :)