Ok, got the IM10 figured out, but looked at a Bass Pro Catalog today and they had IM85.

Folks,

I'm pretty well versed in the basics of the mechanics of materials.

Modulus of elasticity is defined as



Here's the wiki LINK for those who are so inclined.

In layman's terms what modulus indicates is the the ratio of the deflection of a rod vs. the rods mass. Let's say that we have a fixture that the butt of a rod blank is placed in such that only a couple of inches of the butt of the rod is being used. The rod is positioned in the horizontal. We then measure the distance of the tip of the rod to the floor underneath. Next we apply a given load to the tip in the from of a weight. We then measure the distance of the rod tip under that load to the floor underneath. This distance is the deflection. The deflection is a function of the 'stiffness' of the rod blank.

Now the 'stiffness' of the rod blank has several contributing factors. The modulus of the material that the rod blank is made out of is one of them. There are others, among these are the blank diameter, and the mass of the blank.

With any tube one my increase the diameter of the tube keeping the wall thickness the same and get a stiffer tube. One may also increase the wall thickness without increasing the tube diameter and get a stiffer blank as well. The thing here is that doing either one of these two things will increase the mass, and thus the weight of the blank. Going to a higher modulus material is all about going to a material in which an intrinsically 'stiffer' material is utilized to gain 'stiffness' without increasing mass / weight.

There are complications. (Isn't there always....)

Unless there are design adjustments made, going to a thinner wall will cause the 'crush' strength of a blank to decreased, and the blank will become more 'brittle' as well.

There is a heck of a lot of engineering that goes into the design of a truly outstanding rod blank. Indeed, there is no magic number, etc. that can tell one just how good a rod blank will be. It's waaaaay more complicated that that.

TFP

My blank guy would never tell you where he gets them not even me it is very secrete but I would never ask all I can tell you is they are light and one of the best blanks on the market today I will back that up 100%. I will just keep makeing the IM8 like always and leave this to the bigger guys but I will sell you IM!) if you want it...

IM6, IM8, IM10, IM confused

Good read though. Robert you have one rod on your boat for lets say crank baits. What is it? Length action IM# brand name?

Most high end crankbait rods like Loomis are multi modulus. They use different fabrics for different sections of the rod. They may use a high modulus for the butt and a lower modulus or even a little glass for the tip section. I'm a crankbait fool and some might argue a fool in general :), so I have 4 or 5 different crankbait rods, ranging from 7' l/ml to 8' medium heavy.

If I had to fish all my crankbaits with one over the counter rod, I'd use a Loomis CBR903. It's a 7'6" medium with a very soft tip, but enough backbone to muscle big fish if you need to (caught me a 10+ in the trees at Fork). My only complaint is the handle is much too short. I'd prefer 10-10.5 inches from butt to the back of the reel seat. For the money though, I'd recommend you talk to Grant or some of the other custom builders on here. Any good custom builder can build you a better rod for the same cost as the Loomis and maybe cheaper.

I am confused for sure now.

Hey thanks Robert

The variables are endless and each manufacturer tweaks the materials a little differently. Anymore IM is more about marketing than anything else. How the rod performs for you in terms of sensitivity, strength, weight, etc. is more important.

I think Robert has made a Game Effort in trying to explain some Insight on the Term High Modulus Blank. I tend to think the same process( Gyspy- ism) goes on in the Lariat Rope Business. That being that several Companies taking Credit for Coming Out with the perfect Blend of Heel Rope, while in fact its tied by another Rope Company.
*not sure what This has to do with the price of Rice in China- but sounded good at the time

Either way, You gotta believe that Everyone seeks that special feel in a rod and Sometimes people just cant get there buying Them off the shelf at Walmart

I understand exactly where Robert R is coming from. That's why I've already started my process of building a rod and calling it "IM23" and making millions!

I worked in the golf industry and Callaway Golf as an example used several different manufactuers of its graphite shafts to keep up with demand. You could have 10 of the same drivers and not be sure the shafts all came from the same mfg. because the artwork is the same. This could also be happening in the fishing rod business as well. I'm not saying G Loomis is using blanks from China, but I can guarantee you BPS is! And this is not impling that China is not making some very fine knock-off blanks from G Loomis specs, but it is not the same quality as a G Loomis. PS: Robert R - Thank you for your time and sharing of knowledge. By the way, how do you measure the IM rating of a cane pole...ha ha!

Do any of you guys actually make your own rod blanks? Is it worth the process of trying? Also if you do what machinery or equipment do you have (for mass production)?

razorback

To the best of my knowledge, there are no custom builders making their own blanks.

Lots of sophisticated equipment required and very expensive.

No rod builders make their own blanks. Some of us have rod makers build special blanks for us that match specific requirements we have. Making our own blanks is just too cost prohibitive.

It is very expensive. Next time you're at Bass Pro take a look at any line of rods you like, say the BPS Johnny Morris rods. Note how many different sized rods you see in that line up. Each unique sized rod requires a mandrel and they aren't cheap, about $7-10k each. You might be able to use the same mandrel for a 7' medium heavy and a 6'6" medium heavy, but figure a 7' medium that has a different butt and tip diameter would necessitate a different mandrel. So figure 4 or 5 mandrels for a basic series of production blanks/ rods. Now you need a pressure roller to roll the blanks and an oven to bake the blanks.

this has been good post some good info