Today I received a blank I ordered online that I intended to build for pacific salmon. The quality looks quite good - color, straightness, fit, finish.

I measured it using CCS and found:
ERN = 6.49
AA = 69
**note that the blank matches butt size and blank weight as advertised, and I probably should have known it would be too light.

Am I wrong to conclude that there is no way this rod will throw a 9 or 10 WT fly line? I would expect it to be significantly overloaded, even at 30 feet.
Just looking for confirmation that I'm not out of line telling the vendor (not a sponsor) that their advertising is blatantly wrong.
Opinions?

It will load and throw a 9-weight line perfectly, at a very short distance. So their advertising is not wrong, unless they stated that it is intended for long distance casting with that line weight.

Do make sure you measured it accurately.

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By short distances do you mean 10 feet? That's hardly a reasonable assumption for a fly rod.
I checked it twice and subsequently measured a 5wt rod using the identical setup and weight and found only slightly more deflection.

Less than 30 feet.

You might want to talk to the manufacturer (the dealer doesn't assign line weight ratings to rods) and see what they intended the rod for, or even if it might have been mis-tagged.

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Will do. It was a very inexpensive blank so it's not about the $, more the hassle and shipping costs.

Rick,
Can you post blank butt dia. tip dia, weight, length and material along with a mid blank dia.
I can check it to my spreadsheet calculations

Thanks

Eugene Moore

4 piece IM6
length = 105.5"
butt dia = 0.392"
tip = 4.5
blank weight = 1.65oz
mid blank dia = 0.275"

Rick,
According to my numbers the blank should adequately cast a 6.5 to 7 weight line.
Appears you are a little under-gunned if you were planning to cast a 9 or 10 weight line.
Try looking for a butt dia approx .460 at the same length and material mid blank dia should be approx .330

Eugene Moore

Yes, I was looking for a blank with an ERN of at least 9.5 for throwing 75+ feet of 8 wt line with sink tips.
This blank was cheap so I thought I would give it a try. I was surprised to see it so far from expected.

I do not think that butt diameter is an accurate gauge for what line a blank can throw. I have two St. Croix 9wt rod blanks here now and both have ERNs of above 10 and neither has a butt diameter of more than .300. A fly rod blank with a butt dia. of .460 would be a monster!

James,
I've found butt dia to be a very accurate measure of a blank's approx strength.
When included with length, material and weight.
I've an 8 foot 8 weight with a butt diameter of .371.
Marketed as an 8' 5 weight.
The St Croix blanks you mention are most likely a higher quality material and from a more reputable maker.


Eugene Moore

In other words, butt diameter is NOT an accurate measure of a blanks approximate strength.

Eugene,

Can you shoot me an email? Your email is hidden.

Thanks,

Joe

I ran into similar problems when purchasing no-name blanks from a certain on-line @#$%& site. I won't be making that mistake again. I now buy only from companies willing to put their name on the product.

James,
Possibly you can be more specific in the St Croix blanks you mentioned.
I'm unable to find an 9' 9 weight with the .300 maximum butt dia you've stated.

Just my Observation but Every time I get an IM6 blank i have alwas found them to be no power and what I call Mush To soft

I would go for a better brand and a IM 7, 8 graphite

IMHO You got what you paid for

Bill - willierods.com

I do not have ERNs for these blanks so I cannot say how much power they have, but all are sold as "9wt" rods.

T&T Helix .396
Orvis Zero Gravity .360
Orvis Helios .410
St Croix SCIV/II .400
St Croix SCV .385

My older model St Croixs are the brown SCV and have butts of only .290 and .300 yet ERNs of over 10.0. I have several older Loomis IMX 9 and 10wt models that also have butt diameters of under .300 and they also have ERNs of 10 and even 11.

According to info I received at one of Emory's seminars or discussions, a blank built of the same amount of material, but twice the diameter would be 9 times stiffer. I believe stiffness in the calculations goes up by the cube root as diameter increased, it's not a linear amount by any means. The Perigee 5/6 wt fly rods I built have a butt diameter of .5", the same as the 9 wt Perigee I also own, their stiffness at the butt is quite surprising while under a load.

We have a system to rate rod blanks

IF all blank makers used it -- then we would know or at least be in the ball park of what the blank will do and if we want more or less we look for a heaver or lighter blank

It Just Has To Be Used by All

Bill - willierods.com

The problem with ascertaining power by butt diameter alone is that you don't have enough pieces of the puzzle to be very accurate. For it to be even remotely relative, you'd have to have the same material and knowledge of the blank's wall thickness as well. I have more than a few blanks with smaller butt diameters, that are far more powerful than others with larger butt diameters.

The ERN is an accurate means of relative power comparison. You will never find a blank with a higher ERN that possesses less power than one with a lower ERN. Of course, not many manufacturers include this information, so unless you have the blank on hand it can be hard to come by.

Most rod and blank manufacturers actually prefer that you not be able to accurately compare their models to those of another company.

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