What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

Carbon Flox

wirejock

Well Known Member
This is probably a bad practice, but it works. I had a couple divots on the carbon fiber plenum flanges. They needed additional material so the screws wouldn't bend and crack the baffles. I use flox often for tiny fixes like this so I took a scrap piece of carbon fiber and chopped it up with the rotary cutter. Just run back and forth till it turns into fluffy flox. Mix into epoxy just like flox. Matching repair and it's hard as nails.
 
I'm curious what you used to form the plenum to keep the material flat across the engine and not sticking to the baffles.
 
Plenum

I'm curious what you used to form the plenum to keep the material flat across the engine and not sticking to the baffles.

Technically, I didn't make the plenum. It's an RV Bits plenum but I sure cursed it. It didn't fit so I basically made one after it was carved up. I had to cut the flanges off and fab new ones as below. Also had to sand off the gel coat because it was cracking and flaking off. The inlets were layups on molds made from foam plugs. once the pieces all fit, I just added glass to lock them together then removed and finished. It drops right in.

If I were to make one from scratch, this is how I would do it.
Fit the cowls and baffles. Fit so the gap is correct and uniform.
Install the baffles and cowls.
Draw a line on the inside of the top cowl by reaching inside. Basically just the forward baffle and the side baffles.
Remove the top cowl.
Measure and finish drawing the baffle lines on the inside of the top cowl.
Lay down some plastic. Probably in strips due to the curve.
Wax it.
Layup the plenum right inside the cowl. Two or three layers is plenty for a srart. When it cures, transfer the lines before popping it loose.
Trim outside the lines so there's extra. That will yield a pretty close form.
Tape off the inside and outside of the baffles and cover everything.
Wax the tape.
Layup strips of glass all around folding the excess over. Two layers is plenty here as well.
Lay the plenum lid on top
Cure
Pop it loose. It will be an ugly mess but should be attached enough to hold it's shape.
Trim and sand till it fits then add layers inside to reinforce the side flanges and a layer of carbon outside to make it purdy.

Same process works to make the inlet boxes. Layup right inside the baffles then pop it loose and finish on the bench.
Mine is a little different because the inlets are molded to match the cowl inlets and sealed with a sleeve.

A mold is always preferred but the top cowl is basically a mold. The finished plenum will mirror the shape of the inside of the cowl.
 
Back
Top