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nreindel - 10/19/2018 3:42:48 PM

I work for a high end mountain bike manufacturer in the U.S. We currently manufacture our composite parts in Asia. A few weeks ago, a large shipment of our composite bike frames were in port in Japan to be shipped to us when they were hit by a large typhoon. Many of our frames were submerged in sea water for over a week.

By the time we received the shipment, most of our frames had been destroyed due to the aluminum and steel inserts in the frames being corroded beyond repair. However, after some cleaning, some of the parts appear to be usable.

We began assembling some of the salvageable frames, but noticed upon assembly that a lot of them are dimensionally out of tolerance. Could the prolonged exposure to salt water have deteriorated and warped the epoxy in the composite parts? We're trying to figure out if this is an issue we need to address with our manufacturer due to parts not being made to spec or with our insurance due to the typhoon.

Any data on the effects of salt water on epoxy would be greatly appreciated, as it would help us back our claim of the cause of this issue.

Thanks in advance!

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KOSTAS - 10/20/2018 10:42:26 AM

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nreindel - 10/19/2018 3:42:48 PM

I work for a high end mountain bike manufacturer in the U.S. We currently manufacture our composite parts in Asia. A few weeks ago, a large shipment of our composite bike frames were in port in Japan to be shipped to us when they were hit by a large typhoon. Many of our frames were submerged in sea water for over a week.

By the time we received the shipment, most of our frames had been destroyed due to the aluminum and steel inserts in the frames being corroded beyond repair. However, after some cleaning, some of the parts appear to be usable.

We began assembling some of the salvageable frames, but noticed upon assembly that a lot of them are dimensionally out of tolerance. Could the prolonged exposure to salt water have deteriorated and warped the epoxy in the composite parts? We're trying to figure out if this is an issue we need to address with our manufacturer due to parts not being made to spec or with our insurance due to the typhoon.

Any data on the effects of salt water on epoxy would be greatly appreciated, as it would help us back our claim of the cause of this issue.

Thanks in advance!

Really interesting story, when you say upon assembly? , those bike frame come in pieces and then you clue them together ? isn't the parts coated ?
Sounds  funny  because there are many sporting goods made from cf  used in the sea such as surfing ,kiteboarding etc  All of those are UV coated but i guess bike frames should be too.

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oekmont - 10/20/2018 12:23:15 PM

I think he meant the assembly of the bike, not the frame.
Salt water usually shouldn't be much of a problem. The salt itself is mostly a problem for metals, because of their chemical/physical propertys.
Water diffuses into the matrix, causing it to expand slightly. However, in most directions the expanding matrix has to strech the fibres, wich "win" because of their higher stiffness. The moisture uptake is a reversible effect, so once out of the water, the effect will return to normal over time.
If you can see warping by eye, it isn't caused by the water.

+x

 

nreindel - 10/22/2018 9:30:11 PM

+x

 

KOSTAS - 10/20/2018 10:42:26 AM

+x

 

nreindel - 10/19/2018 3:42:48 PM

I work for a high end mountain bike manufacturer in the U.S. We currently manufacture our composite parts in Asia. A few weeks ago, a large shipment of our composite bike frames were in port in Japan to be shipped to us when they were hit by a large typhoon. Many of our frames were submerged in sea water for over a week.

By the time we received the shipment, most of our frames had been destroyed due to the aluminum and steel inserts in the frames being corroded beyond repair. However, after some cleaning, some of the parts appear to be usable.

We began assembling some of the salvageable frames, but noticed upon assembly that a lot of them are dimensionally out of tolerance. Could the prolonged exposure to salt water have deteriorated and warped the epoxy in the composite parts? We're trying to figure out if this is an issue we need to address with our manufacturer due to parts not being made to spec or with our insurance due to the typhoon.

Any data on the effects of salt water on epoxy would be greatly appreciated, as it would help us back our claim of the cause of this issue.

Thanks in advance!

Really interesting story, when you say upon assembly? , those bike frame come in pieces and then you clue them together ? isn't the parts coated ?
Sounds  funny  because there are many sporting goods made from cf  used in the sea such as surfing ,kiteboarding etc  All of those are UV coated but i guess bike frames should be too.

KOSTAS, The front and rear triangles of our mountain bikes each come in one piece. We noticed the dimensions being out of spec when we were assembling the suspension linkage.

I had the same thought as you that if they use composites for water sports, then either the epoxy is not affected by salt water or their composite parts have a coating. Our parts have paint and a clear coat on the outside, but the inside of the frames is raw carbon. Unfortunately, being submerged for a week caused many of the frames to be quite full of sea water.