Graphite Rod Purchase And Im Ratings

[einscodek]

Looking to upgrade my rod and in the process dove into some details regarding graphite etc and just wanted to share some brief general findings.

Agree or disagree here it is:

DISCLAIMER:

There is more to a rod than just its graphite. The resin and the production process are major factors as well.

Resin formulation can vary greatly between manufacturers as can the production process. These are unknown to us as successful methods devised would be considered industry secrets. So this discussion can only hold these factors steady and only focus on the known common factors and that is the graphite supplied by Hexcel rated by their IM system.

MATERIAL OBSERVATIONS:

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Tensile strength improved most dramatically jumping from IM6 to IM8 and then IM8 to IM10

However, shear strength by some measure essentially steady from IM6 to IM10

Compression strength and compression modulus characteristics have also held fairly steady from IM6 to IM10

The weak link here is compression and shear. When a rod flexes, there is both tension, compression, and some shear forces.

So improvements in just material tension#s will not make the rod less apt to fail. In addition, since less IM10 material is used, there is that much less material to confront those compression and shear stresses in a rod flex.

GENERAL CONCLUSIONS: (not a big surprise to most)

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IM10 rods will generally be lighter

..assuming less graphite in the form of IM10 is used in the rod as compared to previous IMs

IM10 rods will be more likely to fail

..especially in the more delicate areas where there is less overall material (such as near the tip) to confront flex forces esp. compression and shear

IM10 rods should be more sensitive

..since the graphite fibers themselves are more rigid and thusly better to transmit vibrations such as fish bites and or lures hitting structure etc.. however the rigidity of the complete rod structure itself is also a factor in sensitivity

BUYING REMARKS:

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FOR RODS FROM SAME MANUFACTURER (assuming the same manufacturing process..resin/production)

IM8 would seem to be a "best buy" at this juncture.

If you are looking for better than IM8, I would skip IM9 and upgrade to IM10 as I do not see the significant material improvement from IM8 to IM9 worthy of the price jump.

ACROSS MANUFACTURERS

It get a little fuzzy since manufacturers may use differing amounts of the same IM material and different formulations of resin and production process. I'd stick with a reputable brand for rods with high cash outlays.

Hope this helps.. any thoughts?

[BobP]

When graphite started being used for rod blanks, the IM rating was useful.  Maybe it still is on lower priced rods made with the same materials and methods used 15 years ago.  But IMO, there is too much variation in how blanks are built and the materials used (graphite, resin systems, carbon fiber, etc) to rate blank quality by the graphite IM number.  Most high end blank builders don't reveal graphite modulus numbers for that reason.  A high quality spinnerbait or crankbait blank might be made with IM-6 graphite as the best design choice.  A worm rod in the same rod series might use IM-10 graphite.  The real measure of blank quality is how well it performs in the application it was designed for.  I wish there was a number for that!

[.RM.]

This subject has been answered many times here in the past...

 

Take a look at these thoughts......

http://www.bassresource.com/bass-fishing-forums/topic/106207-question-for-rod-builders/?hl=%2Bim+%2Bratings

 

Good Luck & Tight Lines! 

[einscodek]

Fully agree the end-product application is the whole point.  However, alot of manufacturers these days are selling technique specific rods and I was considering 3 older generation rods where differences in IM between generations where it came down to the IM as the major difference..its unknown if their resin or manufacturing tech improved as well..

Chose IM10 but nearly went with IM8 on a price point .. both models felt great in hand.  I skipped over IM9 in consideration.

[einscodek]

This subject has been answered many times here in the past...

 

Take a look at these thoughts......

http://www.bassresource.com/bass-fishing-forums/topic/106207-question-for-rod-builders/?hl=%2Bim+%2Bratings

 

Good Luck & Tight Lines! 

Hadn't seen that thread.  Thanks.

[Jrob78]

I so wish IM "ratings" would go away.  It's one of the most meaningless buzzwords in the fishing industry.

[pbizzle]

I so wish IM "ratings" would go away.  It's one of the most meaningless buzzwords in the fishing industry.

There helpful for someone who is new to buying a quality rod but doesn't know what to look for. When used to compare rods from the same manufacturer they're actually really helpful. For example, some one could go to Academy and see an ethos or their camo rod for the same price. They could look and see that the ethos has an IM8 blank while the camo rod has an IM6 blank. Someone who doesn't know how to test a rod may not be able to tell the graphite quality with out the IM rating. ​Now you can't use an IM rating to compare one company's rod to another company's rod.

[Delaware Valley Tackle]

I so wish IM "ratings" would go away.  It's one of the most meaningless buzzwords in the fishing industry.

x2. Ranks right up there with bearing count in reels.

Higher modulus graphite has a higher stiffness to weight ratio which is where the greater sensitivity is derived from. Aside from the blank production variables already mentioned a poorly executed guide train and other aspects of the design can hinder a finished rods performance.

[aavery2]

From what I have read, IM is not a even a standard to which carbon fiber is measured.   The U.S. standard for carbon fiber is Million Modulus and the World standard is Tonnage.   IM is a term used within the fishing industry and varies widely from company to company.

[pbizzle]

From what I have read, IM is not a even a standard to which carbon fiber is measured.   The U.S. standard for carbon fiber is Million Modulus and the World standard is Tonnage.   IM is a term used within the fishing industry and varies widely from company to company.

I've always thought it's what grade of graphite the company's using in the rod. Each company grades their graphite differently though. I mean obviously an IM8 Lommis blank won't be the same as an IM8 Shakespeare blank.

[Jrob78]

There helpful for someone who is new to buying a quality rod but doesn't know what to look for. When used to compare rods from the same manufacturer they're actually really helpful. For example, some one could go to Academy and see an ethos or their camo rod for the same price. They could look and see that the ethos has an IM8 blank while the camo rod has an IM6 blank. Someone who doesn't know how to test a rod may not be able to tell the graphite quality with out the IM rating. ​Now you can't use an IM rating to compare one company's rod to another company's rod.

So what does IM mean?  Why is an IM8 blank better than an IM6 blank?  Why can't you use an IM rating to compare blanks from different manufacturers?  

[pbizzle]

So what does IM mean?  Why is an IM8 blank better than an IM6 blank?  Why can't you use an IM rating to compare blanks from different manufacturers?  

I'm not exactly sure what it stands for but I believe it means intermediate modulus. I know it's a measurement of how dense the modulus is. An IM8 blank will have denser graphite and weigh less than an IM6 therefore being more sensitive. Basically, the higher the modulus the stiffer that graphite will be. So with this stiffer graphite, the lighter the rod can be. A downside of the denser graphite is that it can break easier. It's really hard to brake a quality rod if you're using it how it's meant to be used and most rods are broken from people just abusing it. You can't sling your fish in or high stick with this thinner blank. That right there is why a person in my church bass club broke 2 loomis' s in one day during our June tournament. You can't compare one blank to another manufacturer's blank since it's not really a scientific measurement like an inch or a gallon. I know a lot about my favorite sport for a 13 year old... just can't afford it lol.

[pbizzle]

I've always thought it's what grade of graphite the company's using in the rod. Each company grades their graphite differently though. I mean obviously an IM8 Lommis blank won't be the same as an IM8 Shakespeare blank.

Thought is a bad word to use there. I mean sum it up basically.

[Jrob78]

I'm not exactly sure what it stands for but I believe it means intermediate modulus. I know it's a measurement of how dense the modulus is. An IM8 blank will have denser graphite and weigh less than an IM6 therefore being more sensitive. Basically, the higher the modulus the stiffer that graphite will be. So with this stiffer graphite, the lighter the rod can be. A downside of the denser graphite is that it can break easier. It's really hard to brake a quality rod if you're using it how it's meant to be used and most rods are broken from people just abusing it. You can't sling your fish in or high stick with this thinner blank. That right there is why a person in my church bass club broke 2 loomis' s in one day during our June tournament. You can't compare one blank to another manufacturer's blank since it's not really a scientific measurement like an inch or a gallon. I know a lot about my favorite sport for a 13 year old... just can't afford it lol.

Nice try.  I'm sorry about that, I wasn't trying to pick on you, just trying to illustrate a point.  A lot of people think they know what IM means and what high modulus means and how that relates to fishing rods.  The reality is, "IM" is a term used by one company, (Hexcel) that manufactures carbon fiber, not fishing rods, just carbon fiber.  Not only is IM not an industry standard for grading/describing graphite, it's only used by one company that produces graphite.  Within Hexcel's products, a higher IM number doesn't even mean a higher modulus.   These days, rod company's that use the term IM may or may not even use Hexcel graphite.  The other "ingredients" used in creating a blank are just as important.  The resin and scrim used, the pattern that is used to determine how the materials are put together, the mandrel that the blank is rolled on...all these things make a blank what they are.  

 

My long, rambling point is that "IM" is purely a meaningless marketing term meant to sell fishing rods.  It has pretty much no bearing on the finished product.  It uses arbitrary numbers that give you the sense of quality.  "I mean IM8 has to be better than IM6, right?"  It isn't an industry standard and even if it were, it doesn't describe what people think it does.  Nor does it take into consideration what actually goes into making a blank.  It would be kind of like comparing cakes by the brand of flour used in the mix.

[.RM.]

So what does IM mean?

SM = standard modulus

IM = intermediate modulus

HM = high modulus

UH = ultrahigh modulus

 

[pbizzle]

Nice try.  I'm sorry about that, I wasn't trying to pick on you, just trying to illustrate a point.  A lot of people think they know what IM means and what high modulus means and how that relates to fishing rods.  The reality is, "IM" is a term used by one company, (Hexcel) that manufactures carbon fiber, not fishing rods, just carbon fiber.  Not only is IM not an industry standard for grading/describing graphite, it's only used by one company that produces graphite.  Within Hexcel's products, a higher IM number doesn't even mean a higher modulus.   These days, rod company's that use the term IM may or may not even use Hexcel graphite.  The other "ingredients" used in creating a blank are just as important.  The resin and scrim used, the pattern that is used to determine how the materials are put together, the mandrel that the blank is rolled on...all these things make a blank what they are.  

 

My long, rambling point is that "IM" is purely a meaningless marketing term meant to sell fishing rods.  It has pretty much no bearing on the finished product.  It uses arbitrary numbers that give you the sense of quality.  "I mean IM8 has to be better than IM6, right?"  It isn't an industry standard and even if it were, it doesn't describe what people think it does.  Nor does it take into consideration what actually goes into making a blank.  It would be kind of like comparing cakes by the brand of flour used in the mix.

It's ok. I also think that an experienced angler should just disregard IM ratings and that they aren't really important. Just as important would be the guides and most important of all would be the balancing point (see ***). I was just trying to say that if someone who doesn't know anything about fishing rods goes into a store knowing that they want a rod made by one company they can  use the rating for help choosing.

[WRB]

Today's high end bass rod blanks are more about light weight scrimless construction to improve vibration feed back. Scrim is the thin fiber mat layer used in the traditional design rod blanks that aid in hoop strength and flexing but deaden vibration. With today's high modulus graphite fibers and high strength flexible resins scrim can be eliminated and still maintain light weight high strength rods. Loomis NRX was one of the first rod makers to offer scrimless blanks, ALX Hydra blanks are also scrimless, not sure about St Croix higher end blanks.

The modulus of a fishing rod blank is the total sum of the fibers and resins it is made up with and changes from butt to tip. rating the fiber modulus independently is marketing technique that few rod builders use today.

Tom

[einscodek]

As indicated, across manufacturers the importance of IM can get lost in the differences in resin and manufacture.  For example some Daiwa rods use multilayers of diagonally oriented graphite to twart torsion stresses.  Others may play with this and that.

Not knowing the manufacturing factors, isloated down to one manufactuers which turns out quality rods (in my case I eventually narrowed down my myriad of choices to 2 different IM generations across Shimano Cumaras/Crucials/Compres) then looking at IM may made some more sense to me.

Assuming Shimano manufacturing across lines are fairly consistent and theres no reason not to believe, IM can be more a factor.

Nothing to say you cant use IM to try and evaluate across manufacturers cause the base material is obviously imporant but design and manufacture is as well.

 

I hear higher IMs are more brittle.  I have not seen anything to substantially back this up.. looks to me all the IMs are equally brittle.

I see higher IMs having improved tension max loads but not shear and compression.. no improvement there.

Weak links in chains are where they fail.

These weak links are where higher IMs will fail near the weaker areas of a rod (tips) with less IM10 material used to shave rod weight, it becomes more susceptible to these stresses more so than the lower IM rods.

Now with a different manufacture like Daiwas multilayer crisscrossing, now again we'd be comparing apples to oranges again.. or different apples at least.

 

[Capt.Bob]

I so wish IM "ratings" would go away.  It's one of the most meaningless buzzwords in the fishing industry.

 

 

x2. Ranks right up there with bearing count in reels.

Higher modulus graphite has a higher stiffness to weight ratio which is where the greater sensitivity is derived from. Aside from the blank production variables already mentioned a poorly executed guide train and other aspects of the design can hinder a finished rods performance.

X3!