Do extremes in ambient temperature have a significant effect upon the flexibility of graphite rod blanks? I tried a search but got lost quickly.

By flexibility, I expect you mean the physical characteristics of power and action + durability/fragility. Right?

Within the "normal" range of temps, most likely not. Keep in mind there are graphite ice rods that are used down to about zero, and they seem to work fine. I would think by about - 40 F you would want to be very careful-not sure there is a lot of data for that extreme. I know that many rubber parts get brittle down there. But not all, tires keep working.

I expect companies like St. Croix could answer your question with good credibility.

Not really. Carbon fiber isn't prone to becoming "brittle" in extreme cold nor to loose stiffness in extreme heat. You would have to push the temperature high enough to begin melting the resin for that to happen.

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I do not believe the blank would have any ill effects but as Michael stated rubber gets brittle meaning if I am understanding what he means the guide cushion rings could fail even if they are vinyl nylon, metal tends to move at different temps to hot expand cold shrink .
I my self have guides fail in extreme cold but never in the heat.
The polymer resin used now is cured with high heat and will be fine in the cold kind like the resin used on space shuttle tiles .

The best day to be alive is always tomorrow !!
Think out side the box when all else fails !!!
Wi.

Phil

Cannot find the source, but I remember reading not so long ago that some of the adhesives we commonly use can become brittle and fail in the cold. So, assuming graphite and glass blanks are OK in the cold, we might have other materials in play.

What I was talking about was at -40 F, which is, I believe, way below what any (sane) person would be subjecting a rod to. I was really just thinking about the blanks. Theoretically, considering the guides, I expect the trouble will come from the different coefficients of thermal expansion/contraction between the ceramic and the metal. That may be what Matthew experienced. I'll keep my fishing between about 45 and 90 F and not worry about the tackle.

Think about the many aerospace applications where carbon fiber and related epoxies are used. They experience -40F and more.

One thing I'm sure of - in terms of temperature, my rods are probably tougher than I am.

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Phil’s question is a good one, interested me and got me thinking (Oh no, here I go again!). My composite experience has been limited to heat issues rather than extreme cold. Living here in LA LA Land, when people wake up in the morning with frost on their roof, they freak-out! With only ideas in hand, I contacted the guru at my structural epoxy manufacturer to inquire as to the effects extreme cold has on epoxies and composite laminates. I was flattered to learn my gut feelings were pretty much right-on.
The fabric itself, CF or FG, is effected virtually nil by low (human survivable) temps, say down to -75*F. Epoxies (plastics) in general and by themselves endure lower temps quite well but stiffen which equates to becoming more brittle. Thus, when subjected to sudden stress/impacts may fracture or fail. The more flexible the plastic is at room temp, the better it will endure lower temps. I gave him a couple bottles of ProKote a few months ago and he was initially impressed with its flexibility but has not been able to conduct any further tests.
The issue is that the fabric and epoxy are not separate but rather combined with each other to form an integral laminate, in this case a fishing rod. CF is much stiffer, which equates to brittle, than FG but not all that much stronger. Due to the brittleness, FG is actually tougher than CF which is why so many 300# class tuna rods are still made from FG. When these fabrics are encapsulated in a flexible matrix (the epoxy), the two complement each other and work together to form a strong, pliable laminate (rod). If that matrix becomes stiff and brittle, the two may not complement each other as well, resulting in additional stresses being applied to the fabric fibers. We may be splitting hairs (or fibers in this case), but, while possibly not an enemy, the cold cannot be a rods best friend. To take that one step further, FG may be a better option over CF when fishing huddled over a hole in the ice. While I have recently become rather fond of FG blanks and rods, I have sincerely attempted to omit any bias in this post.
On the other side of the temp spectrum, consider giving all your finished builds a “Post heat cure” of about but <150*F. When cured at ambient, epoxies become stable at that temp but may require many months to actually FULLY cure. Without a post heat cure, when left in the bed of that black pick up, the epoxy can” restart its curing” so to speak, and soften, allowing the surface to become vulnerable to marks or other damage. There are other chemical reaction issues, but too boring to post here. A post cure is simply good practice, required with some epoxies, within the composite industry. The benefits will carry over to rod building as well. While possibly not imperative, it is certainly worth considering. You all have 9tf ovens, don't you?

Mark Talmo
FISHING IS NOT AN ESCAPE FROM LIFE BUT RATHER A DEEPER IMMERSION INTO IT!!! BUILDING YOUR OWN SIMPLY ENHANCES THE EXPERIENCE.

I wasn't so concerned about a graphite rod breaking as I am curious if ambient temperature variations likely to be encountered by fishermen cause a significant difference in the flexibility of graphite blanks? One thing I discovered from my search is that materials engineers do use the term "flexibility" and calibrate it, but I did not see them using the terms "speed" or "power" in describing the behavior of materials (such as graphite or graphite composites) being deformed.

Phil, the "speed and power" come from the form of the object built from the materials, not the materials alone.

Phil,
From the information gathered in my previous reply, I would have to say possibly some but very little. Hopefully you receive hands-on replies from those who huddle over holes in the ice. That is a type of fishing I would like to attempt someday, as long as it’s >10*F!

Mark Talmo
FISHING IS NOT AN ESCAPE FROM LIFE BUT RATHER A DEEPER IMMERSION INTO IT!!! BUILDING YOUR OWN SIMPLY ENHANCES THE EXPERIENCE.

Phil,
I have built hundreds of ice rods. Many of which are used at temps of -20F to -40F.
I have never had a rod returned due to breakage from the cold.

Blank, cork grip, stainless steel guides - no issues.

Be safe

There you have it from a source within the seasoned veterans.

Mark Talmo
FISHING IS NOT AN ESCAPE FROM LIFE BUT RATHER A DEEPER IMMERSION INTO IT!!! BUILDING YOUR OWN SIMPLY ENHANCES THE EXPERIENCE.

Sorry- I should have restricted my interest to the casting performance of graphite blanks. I always use a bobber or a flasher to set the hook while jigging with a rod through the ice, so blank "sensitivity" is not an issue and casting is not remotely an issue. Even a broken ice fishing jigging rod is no big deal to me, but the casting performance of a rod in open water does concern me.

Phil,
I live in LA LA Land where it’s 65*F outside today and am certainly not the best source to give you a qualified answer. Again, my best offering is the previously gathered information and would think it should correlate to affecting casting characteristics as well = little if any, until possibly direct comparisons between casting in Death valley, CA in July VS International Falls, MN in February. Those living in “Four-season” states might be able to afford hands-on observations.

Mark Talmo
FISHING IS NOT AN ESCAPE FROM LIFE BUT RATHER A DEEPER IMMERSION INTO IT!!! BUILDING YOUR OWN SIMPLY ENHANCES THE EXPERIENCE.

Mark: I agree with your last post. The difference is probably close to immeasurable. However, my concern is in keeping with concerns over the weight of a layer of rod finish or 1/400th of an ounce difference in weight between two different brand size four guides.