Non Autoclaved Carbon Fiber

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pmatolcsy
Beefwood
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Joined: Mon May 06, 2013 1:46 am

Non Autoclaved Carbon Fiber

Post by pmatolcsy » Mon May 15, 2017 12:28 am

Hi all,

I'm considering some carbon fiber use in my next build. I built a Lotus 7 type car about 10 years ago , and when I did my reaearch , the consensus was that non autoclaved carbon fiber was more of a cosmetic thing over fine woven aircraft quality fiberglass when used with a high quality epoxy resin . Yes there is a strength gain by using the stronger fiber but the resin matrix will ultimately be what fails unless it cures more fully under heat and pressure like any reaction in plastics . Also in order to get the ultimate in stiffness to weight ratio the resin matrix(epoxy) needs to be used extremely sparingly. Thats what prepreg is all about. There is so little resin that its virtually undetectable on the partially cured pre impregnated cloth.
From my canoe building days , I am familiar with the need to fully saturate the fibers and then remove as much resin as you can to save weight. When reinforcing wood I imagine the same principal applies.
As an aside , Has anyone tried putting a piece of carbon fiber reinforced wood in a medical type autoclave during its setting reaction? I just happen to have access to one. What does every one think the effect on the wood would be of typical medical autoclave type conditions (121 - 134 C (250 - 272 °F) at 100 kPa (15 psi above atmospheric) at 100% relative humidity. Time can be varied . I was thinking of sealing the entire piece of wood with epoxy which could be sanded off afterwards. This would be applied first and allowed to fully cure at atmospheric conditions. Then the layer of CF and epoxy would be applied and put in the autoclave before the setting reaction happens. What do you think will it help?
Typical CF autoclave conditions are 5bar(75psi above atmospheric) and 250F/121C

Phil
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Trevor Gore
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Re: Non Autoclaved Carbon Fiber

Post by Trevor Gore » Mon May 15, 2017 9:40 am

pmatolcsy wrote:What do you think will it help?
There's only one way to find out.

Good luck!

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Steve.Toscano
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Joined: Thu Feb 07, 2013 11:43 pm
Location: Hunter Valley

Re: Non Autoclaved Carbon Fiber

Post by Steve.Toscano » Mon May 15, 2017 11:45 pm

And ill chime in with a - make sure you share your results back here.... 8)

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