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Re: A DIY Carbon Fiber Mast

Posted: Mon Nov 14, 2022 8:04 am
by fallguy1000
Alext wrote: Mon Nov 14, 2022 6:09 am Another test by Dragon Plate

https://dragonplate.com/carbon-fiber-10 ... gh-modulus

Shows strength and stiffness numbers of different grades of carbon fiber. Strengths are nearly equal,
between standard, intermediate and high modulus. I’m more confused now than before.
All about tradeoffs...

UH is stiffest, easiest to break.

Intermediate is hardest to break.

But stiffness can also be driven by thickness.

So, I'd want intermediate, then make it thick enough to meet desired stiffness.

Re: A DIY Carbon Fiber Mast

Posted: Mon Nov 14, 2022 8:34 am
by Jaysen
I’d warn against thickness as it adds weight. Reduction of weight on the mast is big (low weight increases righting moment).

A secondary factor is stated or unstated mast. I stayed needs more stiffness. Stayed can be a bit more flexible. And remember that some bend is required to maintain sail shape.

Re: A DIY Carbon Fiber Mast

Posted: Mon Nov 14, 2022 9:44 am
by fallguy1000
fallguy1000 wrote: Wed Nov 09, 2022 8:25 pm
Alext wrote: Wed Nov 09, 2022 6:48 pm I hadn’t thought of that. I’ll be looking into it.
I think you wrap it with 3M spray glue and then pull the resin.
Don't try this with the pvc attached. It will not work. I am probably being patronizing here, but don't want you to wreck the work which infusion would do now with the pvc creating voids.

Re: A DIY Carbon Fiber Mast

Posted: Mon Nov 14, 2022 7:44 pm
by Alext
fallguy1000 wrote: Mon Nov 14, 2022 9:44 am Don't try this with the pvc attached. It will not work. I am probably being patronizing here, but don't want you to wreck the work which infusion would do now with the pvc creating voids.
Thanks. Fallguy. I had a brief look at infusion. It seems interesting and way beyond anything
I would be capable of.

Re: A DIY Carbon Fiber Mast

Posted: Mon Nov 14, 2022 9:59 pm
by Alext
As for carbon fiber mast, I think it’s going to be a certain amount of guess work,
trial and error to get it right. I’m researching strength and stiffness data trying to
have a better, more informed idea. I don’t feel any further ahead. Not that I’m a
particularly bright guy, but. Each company that produces carbon fiber or does
significant work with it has their own way of testing and their own, often different
data.

Re: A DIY Carbon Fiber Mast

Posted: Tue Nov 15, 2022 10:43 am
by fallguy1000
Alext wrote: Mon Nov 14, 2022 9:59 pm As for carbon fiber mast, I think it’s going to be a certain amount of guess work,
trial and error to get it right. I’m researching strength and stiffness data trying to
have a better, more informed idea. I don’t feel any further ahead. Not that I’m a
particularly bright guy, but. Each company that produces carbon fiber or does
significant work with it has their own way of testing and their own, often different
data.
My favorite composites experts are on boatdesign.net. They will give you lots of crap, but your best bet for advice is there.

Re: A DIY Carbon Fiber Mast

Posted: Sat Nov 19, 2022 10:56 pm
by Alext
Getting to cold now for epoxy. I don’t have a heated space so I will pause.
I’m pretty confident with my trial and error approach, just have to wait and see.
According to a book published by Glen-L “Rigging Small Sailboats”, the force on
this sail would be 100Kg (225 lbs) in a 20 knot wind. The crossbeams (2.45meter
(8 feet) max) support 100Kg with no noticeable flex. The mast 8.6 meters (28 feet)
will support100Kg with about 10cm (4 inches) flex. I will add layers of carbon fiber
to support the sail way track Then test it.