Infusing 6-8mm thick carbon fiber wing mast.

I may be a bit late responding to this thread, but this may be a solution
https://www.youtube.com/watch?v=_J6SGZZolbU
Serial infusion.

Benefits of "Serial Infusion":
1) Simpler setup, without any need for calculations, software or guesswork
2) Less overall length of feed lines (saving the resin trapped inside)
3) No stepping on the laminate ensures that vacuum film is not stressed or pierced
4) Better quality of the finished product
5) Limited or no need of a resin trap
6) Less post curing as using faster resin systems is possible (energy savings)
7) Accurate approximation of resin (needed for each serie and for all)
8) Easier serial mixing of small resin batches minimizes stress to workforce, and possibility of exotherm events

It could also be a solution if you use resins that have a relative short kicking time like polyester resins. The method allows you to keep on infusing even if the start has started to cure.

 

For anyone looking for answers as to how to infuse 6mm of solid carbon fiber. I can say that Vectorply has a carbon with polyester veil, that's designed for infusion. It works well and I had no trouble infusing 6mm of carbon using airtech green flow media up to 4 inches from the vac line. Works a treat. The carbon seemed to infuse at "normal" glass rates, and I set everything up as I do for glass; very impressive.

Paul.

 

Great work!
But Can you give us a few more details ? I can't find the exact product you describe. Are you sure it's not a carbon fabric with a CFM veil? (Continuous filament mat)

What resin did you use and what was its temperature?
How much vacuum?
What was the fiber orientation, I assume you did a test laminate for a mast, so presumably around 60-80% uni directional in the 0deg and +-45 deg for the remainder? Was it all non crimped fiber, ie all stitched fabrics and not woven fibres?

That's about all I can think of for the moment - any other relevant info would be great.

 

The vector ply is c-ltr 1605, which is 520g at 0 and 12g at 90, with an 18g polyester veil and 7g polyester stitching. It's a heavy carbon, so there are channels inbetween the tows.

Resin was MAS infures, and temps were 19C, I heated the resin to 25C before infusing. I don't think it would have made much difference. this stuff infuses very similarly to 800 gsm triax.

The test pieces were 60cm x 120cm infused from the ends to the centre, and the actual infusion was 6m long, and 120 cm around in the centre and 90cm at the ends. It's a bow beam which will take hull loads as well as forestay loads. 3mm carbon overall, and working it's way to 6mm for 60cm in the centre. This is my test infusion before deciding to do a mast. This beam is 3mm - 6mm as described, over and under 12mm foam. So it's a very stiff piece with 12mm total of carbon at centre. It's designed to hold the bows parallel as well as hold the forestay. It's a true third cross beam. I'd have preferred one that simply takes the forestay load, but Kurt was afraid of cracking at the hull skins, so designed this.

Orientation was same as mast, 60% 0, 20% at +/- 45 and 20% at 90. I used glass uni for the off axis on the beam, but carbon fiber on the test pieces, with the same results.

I have yet to send a piece to a lab for testing, but cutting with a jigsaw shows no dry areas to date.

Vac was near perfect, and all fibers were stitched.


It's a great product, but somewhat heavier than most designers want to deal with. You do end up with a slightly rougher surface than 400 gsm carbon uni, but that's to be expected.

Cheers.
Paul.

 

And the infused beam.

 

I forgot to update this thread last year.

I sent samples to the lab last summer (Structural composites Inc, in Florida) for an ASTM C297 test (flatwise tensile test). I figured if the infusion wasn't good, the pieces would come apart within the laminate, and if the infusion was good, it would break at the foam. The cost of the test was $456 US, but the peace of mind is priceless.

The method of testing required 6 samples of 50mm x 50mm square, from the actual beam, of course. I checked with Kurt, and he suggested the best places from which to cut the samples.

Anyway. The infusion was a success. All samples broke apart within the foam. It took an average of 800kg of force to pull them apart.

I think it'll be fine. And I think this gives this thread a nice conclusion, for those wanting to infuse carbon fiber.

Cheers all.
Paul.