The following write up was done by Nev. He is a production manager of an established manufacturing company.

Blanks that snap

Noticed some discussion in another thread about Cropping, which reel seats are best to use, and a bunch of other things.
I’m sure most of the seasoned builders already know this stuff so this is more for the guys trying to figure out some of the black art tricks for building some of the newer carbon light weight rods.
If I remember right, Kil mentioned that his blanks are reinforced in the area of the reel seat. Nothing unusual about that I do the same thing.
A lot of these new blanks are designed with multiple patterns with certain areas that are reinforced and some are even made on multi taper mandrels.
Every position a pattern starts and stops or the taper changes creates a leverage or stress point in the blank.
When I design these lighter blanks I make assumptions where the reel seat will be positioned.
So if I design a blank with a reinforced section under the reel seat and then crop the blank from the butt, the result means the reel seat will not be glued in the optimum position for the blank. I.e. the reel seat will be further forward in relation to the reinforced area.
The main reason I supply 450g and 550g blanks in two length options is to reduce this problem as much as possible. It does affect the deadlift results when testing a blank if the reel seat is moved in relation to the reinforcing.
People will always crop blanks as it is impossible to make the blank at a length that will suit everyone. So here are a couple of tips for rod builders who don’t know the pattern spec of a blank they have brought;
1. Load the blank before building and mark where the changes in action are.
2. Use a gauge and find the changes in OD to spot the areas that have reinforcing patterns; some blanks have more than one.

The aim is to avoid having either end of the reel seat or grip in the same position as where one of these changes in action or OD occurs.
On the top half of the blank you don’t want these changes occurring half way between guides. If you have to change the guide spacing to accommodate this it is better to have more guides than less.

I don’t know how far other companies are taking their designs but when XXXX ask me to design them a new blank I ask them for their build spec and then I design the Blank to match it as close as I can. I then supply CJ with a pattern spec that shows the primary and secondary stress points so she and Graeme can alter their build spec to get the best out of the blank.
For example I know from the number of test blanks I’ve broken, I have to reinforce the areas where the taper rate changes in the mandrel as these are high stress points. Then where I stop and start the reinforcing depends on where the guides will be placed. One of the things you learn quickly when breaking a lot of blanks is that fixing one problem generally causes a failure or change in action in another area of the blank.
Basically cropping some of the parabolic carbon blanks that are out there now definitely requires a bit more knowledge in terms of how the blank was made. Otherwise don’t be surprised by random breakages that leave you scratching your head and asking XXX.

Nev

Don Becker

Nice post Don. I've often thought they should state where reel seat should be placed. Was different in the past. High tech blanks these days make it a little harder to say, "blank doesn't know if it is fly. casting, or spinning".

Interesting that the above post states a blank capable of 35 kg dead lift isn't up to big 300+ # fish. Not that long ago one fished with drag set at 25% of line test. 130# class was about as heavy as it got...so if the blank could handle a constant 15 kg load you could go after anything out there. Showing my age and ignorance I reckon:)

Russ in Hollywood, FL.

Never had a blank snap, never worried about where the seat went relative to any characteristic of the blank, never had a blank listed for one type of reel (spinning, casting, fly) and used with another fail. I've broken two rods, one I stepped on, and one fly rod that broke at a female ferrule when I made a cast. I think I missed that the male had backed out a little.

I think we are "overthinking" all this stuff. IMHO

As blanks get lighter and materials change, these considerations become more important and likely necessary when pushing the limits. Sure, they won't always apply, particularly for older or mid-range blanks I'd guess. But it seems prudent to trust the advice of a guy who designs (and breaks) these things himself.

Keith,

I believe you have an understanding of what happens as people demand lighter and higher performance rods. It is my endeavor to ensure rods/blanks meet expectations prior to selling them. I lost count of the number of rods that I broke and quit counting after 10. They all broke casting within the rated line and lure limits. One company had a break a few inches above the ferrule, a few inches below the ferrule, a few inches above the reel seat, and had 3 ferrules fail (delaminate). The ferrules took about a month of heavy fishing before they failed. I no longer buy blanks from that company.

With another company, the tips were continually breaking. The breaks were typically 6 to 12" from the tip top. Some of the issues were the way in which the rods were packed. Curious as to the cause of the breakage, I took 5 of the rods to the field and cast them at their maximum lure rating of 5 ounces. Not a single tip broke. My conclusion was that the casting technique of the customers was causing a high stick situation. One of the rods did break. I should say exploded. The section from about 4" above the reel seat to about 2" below the ferrule shattered, The biggest piece found was about 6" x 1/2". Poor quality materials, improper packing, and a lack of casting skills made this rod less than a success.

Don Becker