carbon crank scratched - concern?

On Sunday, April 26, 2020 at 9:24:53 AM UTC-7, Ted Heise wrote:
On Sun, 26 Apr 2020 08:55:14 -0700 (PDT),
wrote:
On Friday, April 24, 2020 at 1:41:10 PM UTC-7, Ted Heise wrote:
Hi all,

A couple of days ago I noticed a scratch on a carbon crank.
Pics are he

http://www.panix.com/~theise/IMG_7765.jpg

http://www.panix.com/~theise/IMG_7766.jpg

It's on my tandem, so I'm especially senstive to safety. The
scratch does not feel as if it has much depth to it. I think
it may have happened when I lost my balance getting off, and
could potentially have banged it with the Speedplay cleat on
the bottom of my shoe.

Should I be concerned about failure?

Ted, that scratch is insignificant but it appears to have a
crack in the crank arm. If that is actually what it is you MUST
throw that out immediately.

Thanks, Tom, but I'm not seeing what you may be calling a crack
separate from the scratch. Could you describe the location? I'm
thinking it may be an artifact of the (crappy) photography.

--
Ted Heise West Lafayette, IN, USA

In pictures like that there is always the possibility of a reflection looking like a crack but I am looking at your second picture and it appears to be a crack from the outer side of the arm and moving in towards the upper side of the locking bolt. Expanded and magnified it looks real and it appears to be into the carbon fiber. So give that a VERY close inspection.

Rather than a crack it appears to be a delamination of the material.

On Sun, 26 Apr 2020 13:11:04 -0700 (PDT),
wrote:
On Sunday, April 26, 2020 at 9:24:53 AM UTC-7, Ted Heise wrote:
On Sun, 26 Apr 2020 08:55:14 -0700 (PDT),
wrote:
On Friday, April 24, 2020 at 1:41:10 PM UTC-7, Ted Heise wrote:
Hi all,

A couple of days ago I noticed a scratch on a carbon
crank. Pics are he

http://www.panix.com/~theise/IMG_7765.jpg

http://www.panix.com/~theise/IMG_7766.jpg

It's on my tandem, so I'm especially senstive to safety.
The scratch does not feel as if it has much depth to it.
I think it may have happened when I lost my balance
getting off, and could potentially have banged it with the
Speedplay cleat on the bottom of my shoe.

Should I be concerned about failure?

Ted, that scratch is insignificant but it appears to have a
crack in the crank arm. If that is actually what it is you
MUST throw that out immediately.

Thanks, Tom, but I'm not seeing what you may be calling a
crack separate from the scratch. Could you describe the
location? I'm thinking it may be an artifact of the (crappy)
photography.

In pictures like that there is always the possibility of a
reflection looking like a crack but I am looking at your second
picture and it appears to be a crack from the outer side of the
arm and moving in towards the upper side of the locking bolt.
Expanded and magnified it looks real and it appears to be into
the carbon fiber. So give that a VERY close inspection.

Rather than a crack it appears to be a delamination of the
material.

Thanks, Tom. I will look at it very closely.

--
Ted Heise West Lafayette, IN, USA

On Sunday, April 26, 2020 at 2:59:32 PM UTC-7, Ted Heise wrote:

Thanks, Tom. I will look at it very closely.

Got an update on that Ted? I just sent some photos off to a buyer about my Basso and there was a slight run in the clear coat by the shift cable adjusters that looked just like the tube was cracked.

On Mon, 27 Apr 2020 14:18:40 -0700 (PDT),
wrote:
On Sunday, April 26, 2020 at 2:59:32 PM UTC-7, Ted Heise wrote:

Thanks, Tom. I will look at it very closely.

Got an update on that Ted? I just sent some photos off to a
buyer about my Basso and there was a slight run in the clear
coat by the shift cable adjusters that looked just like the
tube was cracked.

No, sorry. I've been dealing with some hip issues of late, and
haven't pulled the bike down from the hook it hangs on.

--
Ted Heise West Lafayette, IN, USA

On Mon, 27 Apr 2020 14:18:40 -0700 (PDT),
wrote:
On Sunday, April 26, 2020 at 2:59:32 PM UTC-7, Ted Heise wrote:

Thanks, Tom. I will look at it very closely.

Got an update on that Ted? I just sent some photos off to a
buyer about my Basso and there was a slight run in the clear
coat by the shift cable adjusters that looked just like the
tube was cracked.

Tom, in case it still matters, I can advise that I looked at the
crank arm very closely, and found nothing but cosmetic damage.

All, thanks very much for your input on my question.

--
Ted Heise West Lafayette, IN, USA

On Friday, April 24, 2020 at 4:41:10 PM UTC-4, Ted Heise wrote:
Hi all,

A couple of days ago I noticed a scratch on a carbon crank. Pics
are he

http://www.panix.com/~theise/IMG_7765.jpg

http://www.panix.com/~theise/IMG_7766.jpg

It's on my tandem, so I'm especially senstive to safety. The
scratch does not feel as if it has much depth to it. I think it
may have happened when I lost my balance getting off, and could
potentially have banged it with the Speedplay cleat on the bottom
of my shoe.

Should I be concerned about failure?

As an aside, I wasn't paying enough attention when I ordered this
bike. I specifically wanted titanlum for resistance to cosmetic
damage, but would have preferred *not* to have carbon components
(also for resistance to handling damage).

Thanks for any advice!

--
Ted Heise West Lafayette, IN, USA

I have worked in composites, including carbon fiber layups, and don't believe you have anything to worry about. Boeing's carbon fiber layups approached a proven maximum of 1 million lbs. PSI tensile strength.

Carbon fiber is truly a miracle. Carbon is a miracle. Diamonds are a miracle.

Drifting just a little, I remember hearing on PBS that H2O is the secret of life. Well, not exactly. C is the secret of life. What can hydrogen and oxygen do without carbon?

On Sunday, 10 May 2020 17:45:33 UTC-4, 2wheelfan wrote:
On Friday, April 24, 2020 at 4:41:10 PM UTC-4, Ted Heise wrote:
Hi all,

A couple of days ago I noticed a scratch on a carbon crank. Pics
are he

http://www.panix.com/~theise/IMG_7765.jpg

http://www.panix.com/~theise/IMG_7766.jpg

It's on my tandem, so I'm especially senstive to safety. The
scratch does not feel as if it has much depth to it. I think it
may have happened when I lost my balance getting off, and could
potentially have banged it with the Speedplay cleat on the bottom
of my shoe.

Should I be concerned about failure?

As an aside, I wasn't paying enough attention when I ordered this
bike. I specifically wanted titanlum for resistance to cosmetic
damage, but would have preferred *not* to have carbon components
(also for resistance to handling damage).

Thanks for any advice!

--
Ted Heise West Lafayette, IN, USA

I have worked in composites, including carbon fiber layups, and don't believe you have anything to worry about. Boeing's carbon fiber layups approached a proven maximum of 1 million lbs. PSI tensile strength.

Carbon fiber is truly a miracle. Carbon is a miracle. Diamonds are a miracle.

Drifting just a little, I remember hearing on PBS that H2O is the secret of life. Well, not exactly. C is the secret of life. What can hydrogen and oxygen do without carbon?

Do you think that bicycle manufacturers use the same materials as Boeing does?

Cheers

On Sunday, May 10, 2020 at 4:25:58 PM UTC-7, Sir Ridesalot wrote:
On Sunday, 10 May 2020 17:45:33 UTC-4, 2wheelfan wrote:
On Friday, April 24, 2020 at 4:41:10 PM UTC-4, Ted Heise wrote:
Hi all,

A couple of days ago I noticed a scratch on a carbon crank. Pics
are he

http://www.panix.com/~theise/IMG_7765.jpg

http://www.panix.com/~theise/IMG_7766.jpg

It's on my tandem, so I'm especially senstive to safety. The
scratch does not feel as if it has much depth to it. I think it
may have happened when I lost my balance getting off, and could
potentially have banged it with the Speedplay cleat on the bottom
of my shoe.

Should I be concerned about failure?

As an aside, I wasn't paying enough attention when I ordered this
bike. I specifically wanted titanlum for resistance to cosmetic
damage, but would have preferred *not* to have carbon components
(also for resistance to handling damage).

Thanks for any advice!

--
Ted Heise West Lafayette, IN, USA

I have worked in composites, including carbon fiber layups, and don't believe you have anything to worry about. Boeing's carbon fiber layups approached a proven maximum of 1 million lbs. PSI tensile strength.

Carbon fiber is truly a miracle. Carbon is a miracle. Diamonds are a miracle.

Drifting just a little, I remember hearing on PBS that H2O is the secret of life. Well, not exactly. C is the secret of life. What can hydrogen and oxygen do without carbon?

Do you think that bicycle manufacturers use the same materials as Boeing does?

Cheers

The material is the same. The procedures are FAR different.

On Sun, 10 May 2020 16:25:56 -0700 (PDT), Sir Ridesalot
wrote:

On Sunday, 10 May 2020 17:45:33 UTC-4, 2wheelfan wrote:
On Friday, April 24, 2020 at 4:41:10 PM UTC-4, Ted Heise wrote:
Hi all,

A couple of days ago I noticed a scratch on a carbon crank. Pics
are he

http://www.panix.com/~theise/IMG_7765.jpg

http://www.panix.com/~theise/IMG_7766.jpg

It's on my tandem, so I'm especially senstive to safety. The
scratch does not feel as if it has much depth to it. I think it
may have happened when I lost my balance getting off, and could
potentially have banged it with the Speedplay cleat on the bottom
of my shoe.

Should I be concerned about failure?

As an aside, I wasn't paying enough attention when I ordered this
bike. I specifically wanted titanlum for resistance to cosmetic
damage, but would have preferred *not* to have carbon components
(also for resistance to handling damage).

Thanks for any advice!

--
Ted Heise West Lafayette, IN, USA

I have worked in composites, including carbon fiber layups, and don't believe you have anything to worry about. Boeing's carbon fiber layups approached a proven maximum of 1 million lbs. PSI tensile strength.

Carbon fiber is truly a miracle. Carbon is a miracle. Diamonds are a miracle.

Drifting just a little, I remember hearing on PBS that H2O is the secret of life. Well, not exactly. C is the secret of life. What can hydrogen and oxygen do without carbon?

Do you think that bicycle manufacturers use the same materials as Boeing does?

Cheers

To the extent that carbon fiber is carbon fiber, yes. However... there
are many grades and types of carbon fibre :-(
--
cheers,

John B.

On Sunday, May 10, 2020 at 7:34:19 PM UTC-4, wrote:
On Sunday, May 10, 2020 at 4:25:58 PM UTC-7, Sir Ridesalot wrote:
On Sunday, 10 May 2020 17:45:33 UTC-4, 2wheelfan wrote:
On Friday, April 24, 2020 at 4:41:10 PM UTC-4, Ted Heise wrote:
Hi all,

A couple of days ago I noticed a scratch on a carbon crank. Pics
are he

http://www.panix.com/~theise/IMG_7765.jpg

http://www.panix.com/~theise/IMG_7766.jpg

It's on my tandem, so I'm especially senstive to safety. The
scratch does not feel as if it has much depth to it. I think it
may have happened when I lost my balance getting off, and could
potentially have banged it with the Speedplay cleat on the bottom
of my shoe.

Should I be concerned about failure?

As an aside, I wasn't paying enough attention when I ordered this
bike. I specifically wanted titanlum for resistance to cosmetic
damage, but would have preferred *not* to have carbon components
(also for resistance to handling damage).

Thanks for any advice!

--
Ted Heise West Lafayette, IN, USA

I have worked in composites, including carbon fiber layups, and don't believe you have anything to worry about. Boeing's carbon fiber layups approached a proven maximum of 1 million lbs. PSI tensile strength.

Carbon fiber is truly a miracle. Carbon is a miracle. Diamonds are a miracle.

Drifting just a little, I remember hearing on PBS that H2O is the secret of life. Well, not exactly. C is the secret of life. What can hydrogen and oxygen do without carbon?

Do you think that bicycle manufacturers use the same materials as Boeing does?

Cheers

The material is the same. The procedures are FAR different.

There you go. I remember Boeing's layups were very sophisticated vacuum-bagged with heat, sometimes pre-preg, and stringent conditions. But even shadetree carbon layups often attain tremendous tensile strength that boggles the mind.

In the late 80's we had this aircraft builder running a stress test on WLAC White Lightning composite e-glas wings with wet tubular carbon fiber main spars. After he reached 10 "G" forces* by piling sandbags on the inverted wings he kept on going and one of the wings "blew" with an explosion that unloaded considerable energy and sounded like dynamite. That was an expensive little bit of destructive testing.

*Weight of the loaded 4-place aircraft x 10