Bicycle Mechanics - Does extreme heat damage Carbon frames. where i live its 120 degrees in the summer???

Stupid question. I live in the Palm springs California area where in the summer it get hot. i mean hot from 115* to 120* and inside a garadge more than likely
past 130*.

My question is i have 2 carbon bikes . does heat lower the life of the frame any input is welcomed.

Epoxy composites cure chemically , the heating in the mold, if done,
just speeds the curing ,
but once the chemical process is complete, it cannot be reversed.

See any Corvette cars come apart down there? same deal.

I use industrial epoxy resin for boat building and prudent heating is a good way to clean up excess cured goop. Heat will soften epoxy but excessive heat or too many cycles of heating cooling may damage it permanently. Epoxy formulations are designed for particular applications and some have high heat ratings. In general you need at least 400-500 deg F to matter. I would advise not taking a heat gun to your frame, but otherwise if you can survive the heat your bike can too,

BTW: I believe corvettes are made using polyester resin systems - totally different thing.

-G

yea , but those resins don't un catalyze.. Done FG boat building in my past,
Epoxy stinks less while you work with it.

now the UV damage to the polymer chain is well known
and will have some effect over time..
how long? not known, research that in your air conditioned spare time.

Heck, there are big giant Airbus planes flying out there now with mostly composite wing structures using similar resins/epoxies. They are everywhere in the world, in super hot and super cold conditions..........Do not worry, your CF bikes will not asplode in your garage on you during the summer.......:rolleyes::D

Chombi

About the only conditions I can think of where you might do some damage would be if you were to leave it inside your car under the glass for an extended period of time in temperatures of 115. I doubt even then it'd do any harm but I for one wouldn't risk it but that's just me being paranoid with an expensive frame.

I wouldn't be too concerned. The temperatures you're likely to see are well below anything that would phase the CF frame even inside your car. So you should be fine. The risk of theft is much greater. :-) I have very expensive fishing rods that survive great in all sorts of heat in the back of the truck.

Heck, there are big giant Airbus planes flying out there now with mostly composite wing structures using similar resins/epoxies. They are everywhere in the world, in super hot and super cold conditions..........Do not worry, your CF bikes will not asplode in your garage on you during the summer.......:rolleyes::D

Chombi

Boeing ones, too. ;)

It's not the heat it's the humidity or lack of it. I spent the last year in Arizona along the side of the road you see tires that have turned into white powder. Glue rubber and plastic always have unreacted liquids in them. In a low humidity environment these out gas. This allows other chemicals into the interior including acids from the air and salts from the road. Inspect the aluminum parts where they join the fiber such as the dropouts for corrosion.

It's not the heat it's the humidity or lack of it. I spent the last year in Arizona along the side of the road you see tires that have turned into white powder. Glue rubber and plastic always have unreacted liquids in them. In a low humidity environment these out gas. This allows other chemicals into the interior including acids from the air and salts from the road. Inspect the aluminum parts where they join the fiber such as the dropouts for corrosion.

The materials you are talking about are elastomer and thermoplastics which have plasticizers and other volatile organic compounds (VOC's) that give the material useable properties like flexibility. Yes, they do degrade quite quickly in Arizona type of weather. Hoods, seat covers, cable housings, tires, etc can be damaged in this way.

Carbon Frames are made from epoxy which is a thermoset material and does not have plasticizers and VOC's to worry about. As stated above, any temperature range that would start to damage a carbon frame would be fatal to people.

Stupid question. I live in the Palm springs California area where in the summer it get hot--115* to 120* and inside a garadge more than likely
past 130*.

My question is i have 2 carbon bikes . does heat lower the life of the frame any input is welcomed.

Preach it Brutha! It's like you walk out to get your bike and BOOM, it's Dante hot. For me, that's the summertime Three Shastas.

If I were concerned about that I wouldn't have CF frames. Lame as they are, they won't give up at any temperature that won't kill you first.

Here's what the people that I use,that make carbon fiber for top automotive racing teams,say about carbon fiber and heat:


Carbon fibers by themselves can withstand very high temperatures but when used in an epoxy resin matrix the laminate is limited in its ability to withstand heat. The mechanical properties of all materials begin to change when exposed to heat or cold. Sometimes this change is severe and sometimes the change is barely noticeable.

The material used to fabricate tubing is designed to be used at temperatures less than 215F. This does not mean the tube will fail at temperatures greater than 215F. It does however mean that the tubing will begin to lose strength and stiffness beyond this temperature. You may not see any visual change in the material until you reach 350-400 degrees Fahrenheit. At that temperature the tubing will begin to break down and may turn ashen in color.

There are specialized resins that can be used at elevated temperatures. Even with specialized resins 400F is pushing the limit.

You may be aware of carbon fiber clutch or brake disks being used in race cars which would see temperatures well beyond 400F. In this case a carbon fiber/resin laminate is created and then undergoes a coating/curing process in which the part is super-heated to burn out the resin. Once the resin is burned out it is replaced with a liquid silicon based compound and cured again to become a silicon carbide laminate.

So it depends on the resins used and how it's treated afterwards.

This concludes todays basic lesson on carbon fiber and heat.....

chombi

Bad deal using an Airbus airliner for reference. They have and do come apart in flight. At least 3 have had their verticle stabilizer break off. And the huge new 380 has already had cracks appear in their wings. Some pilots wont fly Airbus planes, or let their families fly on them.

chombi

Bad deal using an Airbus airliner for reference. They have and do come apart in flight. At least 3 have had their verticle stabilizer break off. And the huge new 380 has already had cracks appear in their wings. Some pilots wont fly Airbus planes, or let their families fly on them.

only the A380 has carbon fiber used extensively through the airframe. The other ones, in fact, practically all modern commercial airliners are made from aviation grade aluminum.

And bikes are not subjected to the same kind of stresses an airplane goes through.
namely, pressurization cycles and the flexing of the wings.

chombi

Bad deal using an Airbus airliner for reference. They have and do come apart in flight. At least 3 have had their verticle stabilizer break off. And the huge new 380 has already had cracks appear in their wings. Some pilots wont fly Airbus planes, or let their families fly on them.
You might attribute the problems with the Airbusses to bad design. As already noted, there are also other planes from other manufacturers flying with composite wing components....and they are not all falling out of the sky.....
Anyway, If CF bicycle frames were so vunerable to heat, I would not think that all these bicycle companies would be continuing to sell them. The Engineers would have to be so stupid if they do not take into account what kind of environmental conditions the frames would be subjected to.
CPSC might even step in and stop all CF bicycle sales and mandate recalls if this is a justified concern and there's none of that even afer 30 years of CF bikes in the market.

Chombi