Trouble conceptualizing

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#1

Hello,

I have searched and read but have had a hard time conceptualizing the infusion set up for carbon fiber tubes/pipe/shafts. I am making two tubes of 2.75" final diameter that are 51.5" long and so far think that infusion would be the way to go. They are going to require about 5-6 layers of uni directional and multi directional sleeves so that is why i am not to enthusiastic about hand wet layup. What would be the best way to organize my piping? I would also have several other pieces of tubing around the same diameter but different lengths that I wish to make at the same time. Also I have the resin of 207A and 105A from Soller Composites. Will that be a problem for the infusion process?

Thank you in advance for your help,
Morgan

#2

only thing i can think of is aluminum tooling (straight) or using a salt pour(complex curve) which requires aluminum tooling if your using sleeve…unless you do a slit mold.

salt pour is a high heat pour that goes into aluminum tools… then the tools are split and the carbon is layed over the salt. then its bagged and cured… autoclave. or whatever.

then a heated pressure washer sprayes the salt away from the inside…

this makes nice aerospace quality parts.

otherwise try a bladder… but… in any case good luck with that.

shrinkage with that layering and resin is going to be a chalenge… ive used soller before. and delt with them before. very good people. very honest.

#3

In the past I have used a wood or pvc mandrel but it was never this many layers or this long. Right now I am just trying to figure out the best way of wetting the cf. I was thinking of wrapping the mesh around the tube kinda then going onto the next one if that makes sense. I just have seen more infusion for flat or mold parts but not round and don’t really know what to expect or how to set it up.

#4

While I have never done infusion for a tube, I’m sure it will be hard. Normally, prepreg on an aluminum mandrel is the way it’s done, OR filament winding. Bladders with a female mold would also be a way to go. However, with all dry fabric layups, you run the risk of wrinkles. Wet layup is a bit better, because you can spread the resin on the fabric, TIGHTLY wind the tube, and then wrap the part in tape (pressure, or heat shrink) But wet layup is of course messy.
Your need of uni is scary, since Uni does NOT wet out well, even with infusion.
I would avoid infusion at all costs, just because of the wrinkling issue.
Wet layup might be possible if you can tightly wrap the wet fabric, and then use mylar tape to wrap and compress the fabric.
Prepreg is the way to go. You can pressure roll the prepreg onto the mandrel, thereby avoiding wrinkles caused by the secondary compaction (bagging or tape wrap)
Filament winding would be ok, but you would NOT get 0deg uni fibers (unless you can pin the ends of the mold, and wrap the tows around that), and your outside surface would be rough…but you can customize your fiber to maximize what strengths you need.