Recently in conversation the question was put to me about IM Blanks, for example IM 6 or IM7 etc. The question was regarding the meaning of the IM if any. I told him I did not know if there was a meaning to those intials but I would try and find out. During are conversation he impress upon me the virtues of this particular 11 1/2' rod, name of which escapes me, that has a IM 6 blank he uses for float fishing steelheads with a centre pin reel. This got me to thinking about the material and how it might compare to other blanks, for example Rainshawdow blanks which I just built my float rod out of. In short I have been trying to find out more info on the IM blanks and have not been able to through a search on this webpage. Does anyone have some ideas about these blanks or where I can go to ask a few question about there comparability to other blanks in the same class?

Thanks
Steve

Found this doing a search on the web. IM apparently is shorthand for Young's Modulus (why not YM6?). Anyway, I don't understand the technical jargon but thought I put it out as a starting point.

One word on IM6 blanks. I have several personal rods for pike that I prefer the IM6 action. It is a little slower but can be reefed on very hard when necessary. I'm currently building a little 6' UL for small stream spinner fishing on a IM6 blank. I like the softer action with the added strength.



"Young's Modulus

For the description of the elastic properties of linear objects like wires, rods, columns which are either stretched or compressed, a convenient parameter is the ratio of the stress to the strain, a parameter called the Young's modulus of the material. Young's modulus can be used to predict the elongation or compression of an object as long as the stress is less than the yield strength of the material."

I forgot to include this bit on elasticity in the first post. Reading these with rods in mind might help a little with the understanding of the characteristics of a blank.



"Elasticity

Elasticity is the property of an object or material which causes it to be restored to its original shape after distortion. It is said to be more elastic if it restores itself more precisely to its original configuration. A rubber band is easy to stretch, and snaps back to near its original length when released, but it is not as elastic as a piece of piano wire. The piano wire is harder to stretch, but would be said to be more elastic than the rubber band because of the precision of its return to its original length. A real piano string can be struck hundreds of time without stretching enough to go noticeably out of tune. A spring is an example of an elastic object - when stretched, it exerts a restoring force which tends to bring it back to its original length. This restoring force is generally proportional to the amount of stretch, as described by Hooke's Law. For wires or columns, the elasticity is generally described in terms of the amount of deformation (strain) resulting from a given stress (Young's modulus). Bulk elastic properties of materials describe the response of the materials to changes in pressure."

IM6 does not have an "action." Rod action is independent of the material it is made from. You can make a fact action blank from hickory, and a slow action blank from IM6.

Two blanks made from the IM6 material can have widely differing actions, powers, speeds, etc. Blanks made from IM6 graphite run the gamut from soft, slow blanks (or soft, fast blanks), to very powerful fast, stiff blanks ( or even slow, stiff blanks).

The design; the taper, determine action. Wall thickness and diameter play the main role in power/stiffness. Of course, all intermingle to some degree.

But there is no such thing as an IM6 "action." An IM6 modulus to be sure, but not action or power. Those come from the design.

IM is generally regarded as meaning either Intermediate Modulus" or "Military." Depends on who you ask.

...........



Edited 3 time(s). Last edit at 01/11/2005 10:02AM by Tom Kirkman.

Steve,
There are two different definitions for IM and I am not sure which was the original. The first is Inermediate Modulus and the second is Improved Military.
For a description of the properties of the materials that todays rods are made of and definitions of stress, strain, modulus of elasticity, tensil strength etc. and for those characteristics for IM6, IM7 etc. go to the following past issues of RodMaker, Volume 6 #6 and Volume 7#1. There is a two part article in those issues that should lay this out for you. If you still have questions after going over the article send me an e-mail and I will try to help.

Steve,
Sorry that should have been Intermediate Modulus not Inermediate Modulus.