Tom,
Is there any chance that you might consider marketing a CD (with printable photos) or annotated photo album documenting the various breaks that you've documented? I'd certainly like something like that to use for customer education (as well as for warranted / non-warranted repairs).

It wouldn't sell well enough to offset the cost of producing it.

The article will be in the Volume 12 #6 issue of RodMaker and hopefully that'll suffice. That was the purpose of breaking all these rods, which as of lunch today, had reached 142 broken blanks.

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Perhaps a live-action video might become a best seller? :)

Not much to see - things happen fast.

I will mention this - a sound rod blank, even among very high modulus rods, is quite a remarkably strong structure in terms of simply applying a load to it and seeing what it will withstand. This afternoon we've been doing load limit failures. The rods are used properly and never taken beyond a 90 degree bend. The flex travels down the blank and the eventual failure always takes place just forward of the handle - point of effort (in fact, the sudden shock from such a failure often results in at least 2 more breaks up and along the rod).

Working with a popular manufacturer's 6 foot, 3-power bass blank, we're finding that they can easily withstand 23 to 23.5 pounds of deadlifted load without damage. The same blanks, given a sharp impact rap will fail under just a couple pounds when that impact takes place in the lower half of the rod. In the upper half, such an impact will result in failure from just a few ounces. And this is with impact damage that is almost imperceptible to the naked eye.

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Tom,

That post, or part of it, above should be on every rod sold!!!

DR

I understand some of the problems / issues with production and marketing as a result of DVD production. How about "Can I buy X-number" of your digital photos for illustration? "These snapped due to 'high sticking'; these blew up because the reel drag exceeded the rod recommended line rating; these were stepped on and then stressed ...... that sort of thing. Maybe 3-4 examples of each.... SASE plus check for X $ for 8x10's right off a printer. Why? Because although I've seen them and repaired them I've seldom taken photos prior to the repair and any photo you take would exceed my photographic skill level. That might be more "doable" if Kinko's is willling to make the prints on an 'upon demand' basis. I know I'd sure like to have a set for my rod catalog.

Tom,
I have seen this phenomina of multiple breaks numerous times and I am not sure but I think the reason for it is that the tensile and compressive strength of the material drops as the load is applied rapidly. A very fast impulse that is the result of the blank breaking travels through the blank very rapidly and exceeds the materials strength because the strength is much lower to loads applied at high speeds.

As far as what you are observing that is the result of a sharp wrap to the blank is concerned, I think that is the result of the fact that a blanks stiffness and also the load on the fibers goes up at the third power of diameter. A sharp rap that damages the surface layer or layers of material results in the blanks lod carrying capacity being reduced dramatically because those surface layers are the ones that are carrying most of the load.

That would make a great episode of "Myth Busters"!


Walt

Tom's work is validating the failure of blanks that has been discussed many time on this Forum. It apears that his work is throwing water on the Fire that I have been accused of "playing with"! I hope his fire extinguisher is loaded enough to completely put out the Fire once and for all! Multiple failures such as the one described by Tom are called a "good break" by several representative who work for top knotch blank companies. Failue rates for "power techniques" using high modulus short bass rods are a problem for rodbuilders. It is highly common and is the largest source of warranty claim that I face.

Tom curious - something else is common in every case - when the call they say " Mr. Bill another one broke - it sounded like a gun going off and it is in three pieces just like the last one"! Did you hear a very common noise like a gunshot?

[rodbuilding.org]



Edited 1 time(s). Last edit at 10/29/2009 08:37PM by Bill Stevens.

Nothing that I'm doing is breaking new ground. We've always known why and how rods break. The point of all this isn't to try and understand what breaks rods or why - we already know all that. It's old hat.

However, few rod builders know how to look at a break and recognize the tell-tale signs that identify one break from another. Each type of break leaves its own tell-tale signs. That's the point of the article and photos - to educate rod builders as to what the different breaks indicate with regard to the particular cause.

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Bill,
A number of years ago I had a bunch of blanks that basically cost me nothing and most were seconds that I was not going to build rods from and I was curious about the breakage modes and decided to break a bunch of them to see how they broke. It is very surprising, as Tom pointed out, how large a load it takes to break a blank if the load is moved toward the butt of the blank. It can also be very spectacular when some blanks break. It not only makes a lot of noise, as you are suggesting, but sometimes pieces fly all over the place at high velocities. I had one piece hit me on the outside of my right hand and give me a pretty good cut as a result. My set up was crude, I used a boat wench to apply the load and sometimes the rope would also come flying back at me at high velocity when the blank broke. I assume that Tom is taking a safer approach than I did.
Your problem with high modulus blanks may be something called "strain energy". It is the area under the stress/strain curve and is the indication of how much energy that a material will absorb before reaching its strength limit. As the modulus of elasticity of a material goes up the strain energy of the material goes down in direct proportion to the increase in the modulus of elasticity. In other words high modulus is not as tough as intermediate modulus and intermediate modulus is not as tough as standard modulus and even standard modulus has only about 1/4 the strain energy of fiberglass.

There's more to it than that. The most durable blanks we've fooled with in all this have actually been the ones made from the highest modulus fiber. They have been much more resistant to damage or failure due to impact, fracture or crush. We rigged up a little machine that will drop an edge against a rod blank and guarantees the same amount of force, at the same angle each and every time. The ones most resistant to impact damage and subsequent failure have been the ones made from the highest modulus fibers. But there's a reason for this - a small diameter, thick walled design.

The higher modulus blanks have also been the hardest ones to break with load limit failures. This is again due to the particular design which incorporates a smaller diameter and much thicker walls. The only problem with such a design is that it tends to negate much of the weight advantage that the higher modulus fibers offer to begin with. You have to use a lot of material in such a small diameter, thick wall design in order to achieve the desired stiffness.

The fact that you have a blank made from high modulus fiber does not automatically make it less durable nor more prone to breakage than a blank made from a lower modulus fiber with a higher strain rate. The design of the particular blank plays a major role in how tough or how strong a rod is.

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Tom,
Yes, you can offset some of the undersirerable properties of the material with design changes. But when referring to the strengths and weaknesses of a material it is assumed that all other variables are held constant. If you do not make this assumption then there cannot be a rational discussion about any of the properties of any material or any design.
In other words it makes no sense to talk about one design using high modulus material and a completely different design using an intermediat modulus material it the point of the discussion is the properties of the material. Or to put it more simply the design changes that you are talking about being made to the design when using high modulus material can also be made to the design using intermediate modulus material.

Therefore to perform a laboratory "clean" experiment it would be necessary for someone to change only one variable - the modulus; use the same mandrel; same wall thickness; same setting/wetting agent; same curing temperatures and times. Very unlikely to be sure - and would probably meet all types of resistance across manufacturers. All in all as the intent is to characterize / photograph what this or that break looks like it's probably immaterial/extraneous to consider modulus since most of these failures are likely due to customer error / mishandling / misuse. I think - but I certainly could be wrong that an IM6 or an IM8 "high sticking" break is going to look the same.

Emory,

I wasn't discussing the properties of the material - I was discussing the end product. The fishing rod. This is what we fish with. The article is intended to provide practical help to builders who need to know how to better identify what caused a breakage. I'm not concerned about any sort of discussion on material properties - that won't provide any practical help for this particular problem.


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Ken,

They will indeed look the same, or at least exhibit very similar telltale clues about what caused the break.

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Tom:
The fact that you have a blank made from high modulus fiber does not automatically make it less durable nor more prone to breakage than a blank made from a lower modulus fiber with a higher strain rate. The design of the particular blank plays a major role in how tough or how strong a rod is.

This is why I start to worry about high Modulus blanks. Durability. Because builders and fisherman and woman , want a lighter blank to fish all day - where and how does one find out about, say breakage rate on a certain blank. Or the thickness of the walls, because most want lighter, companies make the walls thinner, and there for more prone to breakage when hit by a lure or fly ?
I don't think many builders want to say that they have had so many repairs from x-company.

Bill - willierods.com

The less substantial a blank is, i.e., thinner walls, the more susceptible it can be to be to things like impact, fracture, crush, etc. There's a little more to it than this but I don't have time to get into it right now. That's sort of outside the scope of the article.

If you know you have a customer that is hard on his/her equipment, I'd steer them to a lower modulus blank anyway, unless you feel they can appreciate the difference and are willing to have you educate them on the proper way to use a rod and those things that tend to damage them. It isn't hard to make a nearly indestructible rod and it isn't hard to make a super light, highly efficient and extremely sensitive rod. But it remains difficult to do both at the same time.


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Edited 1 time(s). Last edit at 10/30/2009 02:00PM by Tom Kirkman.

The latest "this broke on me" story:
Customer went salmon fishing in upper New York state & came back with a broken rod. "It broke when the fish was on a sandbar (beached). I don't know why it broke but here it is". The break was in the tip section of a two part spinning rod that I made from a steelhead-type blank about an inch below the first guide on the tip section. As it turned out the reel was still on the butt section of the rod. Penn 4000 spinning reel spooled with 40lb Power Pro braid & 30 lb mono shock leader. The drag on the reel was cranked so tight that the reel "jumped" when the handle was turned (drag washers were compressed). When the break happened it must have been fairly "spectacular" as there were pieces of the rod missing at the break point and his buddy said "I thought someone shot off a .22" ....... I have replaced the tip with a new tip and I now have yet another rod for myself using the new butt section and the repaired broken tip.

That is user error. Not the blank or builders fault. I just think of Durability, with all the high end blanks being made with thin walls, prone to breakage. I don't like to repair some thing I built.

Bill - willierods.com

Tom Kirkman wrote "Nothing that I'm doing is breaking new ground. We've always known why and how rods break. The point of all this isn't to try and understand what breaks rods or why - we already know all that. It's old hat.

However, few rod builders know how to look at a break and recognize the tell-tale signs that identify one break from another. Each type of break leaves its own tell-tale signs. That's the point of the article and photos - to educate rod builders as to what the different breaks indicate with regard to the particular cause. "

I personally will be one of those that will be looking forward to all that can be gleaned from your tests & pictures.
Jeff