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chophop
Joined: 16 Apr 1996 Posts: 230
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Posted: Wed Apr 10, 2013 12:17 pm Post subject: Do Masts Degrade with time? |
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At a local dealer they have the new x 100 mast or the old x combat (90% carbon) for the same price. The sales person says he thinks the old one is better. BUt it is 3-4 years old. Surely it has been kept in a dark place a mast bag so no risk of UV damage but does the sheer passage of time render the mast more brittle and subject to breakage? |
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beallmd
Joined: 10 May 1998 Posts: 1154
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Posted: Wed Apr 10, 2013 12:39 pm Post subject: |
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Yes. But 3 to 4 years old is not bad. The bigger problem is the degrading of the windsurfer himself, at least that's my problem. |
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isobars
Joined: 12 Dec 1999 Posts: 20936
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Posted: Wed Apr 10, 2013 1:01 pm Post subject: |
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A heavy bud who sails the OR coast regularly is at something like 18 years on his main mast, a Nolimitz Skinny. 'S good enuff for me. |
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BRIMAR
Joined: 03 May 2004 Posts: 115
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Posted: Wed Apr 10, 2013 2:08 pm Post subject: |
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IMHO Neither the carbon, Glass, or Epoxy resin will degrade over time without UV damage.
There making huge transport category Aircraft with pure carbon now so I have to think the Age of material is not a factor.
Hull expectancy duration is a pretty long time There are aluminum aircraft still flying around that are pretty damn old so I have to think Boeing and Airbus are expecting at least 25 years from each new carbon hull.
No does Carbon Degrade over time with heavy use?
I used to not think so but I have had pure Carbon Ice Hockey sticks that definitely become "Noodley" after about a year.
Hope this helps,
Brian |
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U2U2U2
Joined: 06 Jul 2001 Posts: 5467 Location: Shipsterns Bluff, Tasmania. Colorado
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Posted: Wed Apr 10, 2013 2:30 pm Post subject: Re: Do Masts Degrade with time? |
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chophop wrote: | At a local dealer they have the new x 100 mast or the old x combat (90% carbon) for the same price. The sales person says he thinks the old one is better. BUt it is 3-4 years old. Surely it has been kept in a dark place a mast bag so no risk of UV damage but does the sheer passage of time render the mast more brittle and subject to breakage? |
you actually have 2 questions
Q # 1 to believe what the sales person says
Q.# 2 will it degrade without use.
#1 . your guess as good as mine
#2 .I think it won't start to degrade until it is exposed to UV , and the bending//stress of sailing . _________________ K4 fins
4Boards....May the fours be with you
http://www.k4fins.com/fins.html
http://4boards.co.uk/ |
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bred2shred
Joined: 02 May 2000 Posts: 989 Location: Jersey Shore
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Posted: Sat Apr 13, 2013 12:23 pm Post subject: |
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The primary factors that degrade a mast are due to UV exposure and handling. Don't leave your mast out in the sun, don't whack it into the side of your car, drag it on asphalt, or rig you sail with a pile of sand between the cams/boom clamp and the mast.
A distant second would be cyclical stress. Composites will develop micro-fractures over a long duration of cyclical loading, but as pointed out, these same materials are now being used in commercial aircraft that are expected to undergo cyclical stress for a period of decades.
An unused mast which has been kept out of the sun should be no problem. I would just make sure that it has not been stored on a rack by a window where it was exposed to daily sunlight over a period of several years.
sm |
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U2U2U2
Joined: 06 Jul 2001 Posts: 5467 Location: Shipsterns Bluff, Tasmania. Colorado
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Posted: Sat Apr 13, 2013 3:46 pm Post subject: |
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whated he said above
plus I would take some measure to assure that its storage life was NOT
next to a Roller Skating rink , a ice hockey arena or a GO GO establishment,
all those vibrations would could possibly effect its sell by date _________________ K4 fins
4Boards....May the fours be with you
http://www.k4fins.com/fins.html
http://4boards.co.uk/ |
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GURGLETROUSERS
Joined: 30 Dec 2009 Posts: 2643
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Posted: Sat Apr 13, 2013 4:41 pm Post subject: |
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A woman on one of my Wagner recordings ought to be able to shatter glass at 50 paces when at full belt, judging by what she does to my ear drums. I make sure my masts are well out of her reach!
If carbon does degrade in U.V. light, and under vibration stresses, it surely wouldn't be allowed (safety testing legislation) in applications such as road bike frames and forks and wheels, if life span was so limited. Road surfaces are rarely smooth, and we all like topping 50m.p.h. down steep hills, often with considerable jarring, so should we still be riding 4 or 5 year old carbon bikes?
Surely there must be differing grades of carbon and resins, for the stresses of certain applications? |
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bred2shred
Joined: 02 May 2000 Posts: 989 Location: Jersey Shore
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Posted: Sat Apr 13, 2013 6:58 pm Post subject: |
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GURGLETROUSERS wrote: |
If carbon does degrade in U.V. light, and under vibration stresses, it surely wouldn't be allowed (safety testing legislation) in applications such as road bike frames and forks and wheels, if life span was so limited. Road surfaces are rarely smooth, and we all like topping 50m.p.h. down steep hills, often with considerable jarring, so should we still be riding 4 or 5 year old carbon bikes? |
Off topic from the original post, but to answer your question, it all depends on build quality. I've got carbon masts that are well over ten years old that are still going strong and I've had carbon masts snap on their second outing. There's no reason this would be any different for a bike frame. Carbon fiber is not a magic material. Components which are built using carbon/composites still have to be properly designed and used within their design range or they will fail. If you buy a good quality bike, I imagine it would last for many years. If you buy junk, well, you get what you pay for.
sm |
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DanWeiss
Joined: 24 Jun 2008 Posts: 2296 Location: Connecticut, USA
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Posted: Sat Apr 13, 2013 8:59 pm Post subject: |
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This chart illustrates the wide variety of carbon fibers in the market. Note that high tensile modulus is almost inversely proportional to tensile strength. As the fibers become higher modulus, they also tend to become less strong and less stiff. Modulus is a measure of elasticity as I understand it, and commonly mistaken as a measure of stiffness. Stiffness is more a function of the matrix used when assembling a resin-fiber laminate -how the resin/epoxy bonds to the fibers and how the carbon fibers align to the forces applied
As we've seen most racing masts use high-mod fiber, we can expect and do see that they are less strong and will fail with less force applied than masts with different lamination matrices. I suspect this has much to do with a compromise between making a mast sufficiently elastic (high mod) and sufficiently sting but not too heavy. And not too expensive.
Carbon fiber masts will fail just as any mast if the matrix fails. Simply using a modern carbon mast (cycling it in and out of column) should not show a marked drop in breakage resistance, nor a meaningful drop in performance. But any damage to the matrix may either individually or in concert with other damage, cause the mast to fail.
UV degradation of the epoxy is one way to damage the matrix. Dropping it on a rock and point loading are others.
Sitting inside a bag, inside a shop, a mast will not "age" of loose any noticeable strength or performance unless damaged by impact or fire or something.
As for bikes, they must not only deal with moving in and out of column but point loading and torsional forces. And, making a bike frame has more in common with making a boom than a mast. _________________ Support Your Sport. Join US Windsurfing!
www.USWindsurfing.org |
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