Imperfections Carbon Mast

[IDAVIS]

Hi, i am interested in buy a carbon mast, but I heard than iths normally have imperfections in manufacturing in all brands, its normally becouse are hand made...

Are this true?

Thanks

[jumptheshark]

I think most of the established players have their manufacturing pretty dialled in. Still, many will paint the flared flange from mast to mast base at the top and place their logo there to cover what is usually the ugliest part of the lay up. The mast itself in most cases are quite clean as its usually pre greg and on straight parts like that people with experience can get a clean lay up pretty much every time.

In any case, there is a difference between structural strength and cosmetic perfection and I would not stress over cosmetics unless your willing to pay the big bucks for something like Ketos. That stuff is art.

I ride a Lift foil and its not the same piece of beauty when held in hand next to a Ketos, but is still a lovely piece of craftsmanship visually and an absolute pleasure to ride.

[jakemoore]

The imperfections that are more noticeable come from transport, setup and riding. I wouldn’t worry about it unless you plan to hang it for display and never ride.

[plummet]

Just buy and ride. You are over thinking it.

[IDAVIS]

I see Slingshot Mast with this imperfections

https://ibb.co/q1YZPyH

Its like a área sanded.... Are normal?

[SMJ]

Trade-offs as with everything else in kiting. Yes, you can often spot imperfections right out of the box with carbon. It's also more brittle in cold weather (I've snapped 2 masts hitting bottom), but it's also lighter.

[IDAVIS]

Trade offs?

[BayAreaKite]

Here's a handmade carbon mast with fewer imperfections, because it avoids the top flared area which is a poor structural design: http://www.projectcedrus.com Also made in USA, not China.

Carbon masts shouldn't "break in cold weather." I designed carbon structures for the Boeing 787 which regularly sees temps of -50C, for 30 years. If masts are breaking, it's more design/manufacturing... not the fault of the material.

[SMJ]

If you whack bottom hard with a carbon mast, you can break them. I know this because I have broken 2 carbon masts and have the pics. I've never broken an aluminum mast - which is cheaper in cost but heavier in weight. Trade-offs.

[BayAreaKite]

I am sorry @SMJ, but that is a gross generalization and shows a general misunderstanding of material properties. Standard modulus carbon fiber is at minimum 5x the strength of aluminum (1400MPa vs. 300MPa). It is also 18x stiffer than aluminum (125GPa vs. 6.8GPa). If you are breaking carbon masts, it is because they are poorly designed and manufactured. Yes, even the big brands are still learning about composites and don't necessarily know how to make them stronger than their aluminum masts. This is why I would never buy a carbon mast from a big kite brand, and decided to build my own. There is a reason all high performance cars, bikes, and airplanes are made out of carbon fiber: it is stiffer and stronger than aluminum.

Sometimes people confuse the failure "mode" of a material with the strength. Yes, carbon has less elongation before failure than most metals, which means that it tends to fracture catastrophically whereas metals can dissipate energy through plastic deformation before ultimate failure. But again, with proper design, composites can have better toughness and energy absorption than metals. Remember the recent F1 crash where the driver walked away after he crashed into a barrier then caught fire?

I am not here to sell my mast, I am here to educate. I am a mechanical engineer with 15+ years of experience in the composites industry. I have had customers run Project Cedrus into the bottom as well and it has broken their fuselage or their board. Not one Project Cedrus carbon mast has ever failed in use, and that is even with some of the new 1m wings and 100+ L boards. So that's great that you have pictures of broken carbon masts, but that proves nothing more than those masts weren't strong enough.