[Rob Brownfield]

All exceptionally interesting. Here is one for you then, many years ago I used to build rods for Somers Tackle when they were still located in Thistle street and Jim was still alive.

The blanks were all Hardy Fibatube and two piece.

I found that by placing the rings on the butt section on one side of the preferred plane and the tip rings on the other you could "tune" the rods for different casting styles.

When it came to the 15 foot salmon rods I would ask the customer what kind of casting they did...and whip the rings on the accordingly, on the slightly stiffer side for overhaed casting and softer side for roll/spey. Taking two rods to the river whipped this way you could tell which rod was which by the difference in action.

David,
a question for you, what difference does Autoclaving make to the spine/spline. I ask because I have two Century blanks at home just now (Barbel) and I am struggling to find a spine on them!!!

[David Norwich]

Hi Rob,

Autoclaving - this assumes it is done on a rod blank by any rod company- which I have to be honest and say I very much doubt, would make no difference to the way the carbon fibre pattern is rolled on to the blank.

It has to begin and end somewhere. Vacuum bagging which autoclaving is just a variation of, just replaces any other techniques used for compressing the prepreg carbon fibre in the curing oven, autoclaving, will not change that. Autoclaving is more usually used for making odd shaped parts such as bits for F1 cars, wings and the like, not thin tubes.....

If your rod has faint spirals in the finish that have been ground or sanded smooth. It is definitely not autoclaved. If it is coated with an opaque finish so you can't see the spirals. That prevents you checking that out I'm afraid.

 All blanks have some sort of spine. The way they are made, a bit like rolling a cigarette, means there has to be. The pattern is put on the mandrel and rolled under pressure. The pattern must end somewhere, and it leaves a thicker overlap in the wall of the blank.

 Or if you want to look at it another way, a slightly thinner area around the rest of the blank.

Using very thin pre-prepreg, which equates to more wraps to get a given wall thickness (a technique I use) can reduce, but never eliminate the effect of the overlap.

Are you trying to locate the spine or preferred plane of bending with the guides fitted?

Regards,

David.

[Matt Henderson]

David and Rob,

cracking couple of posts there very informative.  I however have a question. 

David you mention that the spline/PPB comes from a thicker and thinner part in the plank effectively where the first wrap starts from.  I take it this assumes that the first wrap started in a straight line which runs in the same place reference to the centre of the blank all the way to the tip.  If this firts wrap was diagonal rather than straight could you effectively eliminate the spline?

Cheers

Matt

[David Norwich]

Hi MDH,

The material has to be unidirectional or unidirectional carbon fibre prepreg is not doing its job properly.

Reinforcing can be put on in a diagonal pattern as a weave or bi directional, either within the matrix or on the surface.

The main material that gives the rod shaft stiffness on ALL blanks, despite what you may see on the surface as a weave or pattern, must be laid up unidirectionally from butt to tip or the rod shaft material will not operate in compression or tension properly when flexed.

The carbon (or glass) pattern has to start and end at some point. It can't be moulded on. Carbon comes in sheets that the patterns are cut from then placed on the mandrel.
 


Have a look at my YouTube video at the carbon material being cut and you will see how it is prepared. Some of that footage shows the butt section of Mike Barrios Outcast 9ft 5 weight rod blank being made.

 Here is a picture of me holding up some carbon pr-preg patterns that will shortly be turned into a 5 section 13.5ft Norwich EV4 Salmon fly rod.

http://www.davidnorwich.com/images/PatternscutOpt.jpg

David.

[Rob Brownfield]

Hi David,
Thanks for your reply.

The blank has a woven finish to it, and on close inspection, I cant see a join at all. I believe the blank is a two stage construction, with a central core of "normal" carbon and then an outer wrap of woven carbon/kevlar bonded to it to increase hoop strength when casting big leads. The pattern is not just cosmetic, you can see the weave on the last 6 inches of the butt as it is unfinished.

I wonder if the two "layers" are rolled so that the spines contradict each other in position and thus producing a blank that does not seem to have a preferred bend?

The blank is then autoclaved to compress the two materials together and to force out any bubbles from the weave, thus producing a stronger rod...well, thats what the advertising blurb says.

I wonder if the spine is harder to find purely becuse of the poer and thickness of the wall? I seem to recall the old fibreglass carp rods I used to build had less well defined spines than the carbon ones that replaced them...wall thickness?

[David Norwich]

 Hi Rob,

I've made my comment already on what I know an autoclave is used to manufacture.
If you are in any doubt, you can read for yourself http://en.wikipedia.org/wiki/Autoclave_(industrial) just what an autoclave is and what it is used to make. It isn't used to make fishing rod blanks.

You have to accept "Hype" is a major part of selling any product. Do you honestly believe that the worlds rod manufacturers who tape wrap their blanks then cure them, have air bubbles trapped in them due to an inferior manufacturing process? Sage, Loomis, Shimano, Harrison, Hardy, Winston, Thomas & Thomas. David Norwich etc. We all have it wrong?  ???

It may be possible, but I honestly doubt any spine bias is corrected by an overlay of woven carbon fibre in any blank type made by any manufacturer. If it could be done, it could not be done on a fly blanks without a serious weight penalty, as overall the blank would just be far too heavy carrying around a woven overcoat. The reulting performance would be poor because of that alone.

Your glass blank spines where likely more difficult to find because the material is totally woven. Glass is also of a very low modulus of elasticity. Glass fibre rod construction doesn't use unidirectional  fibres in the same way as carbon fibre blank construction.

Catch you later. Got to get back to work... 


Regards,

David.

[Rob Brownfield]

Hi David,
Have sent you a PM with a link to the rod blank manufacturers section on autoclaving in the rod building industry. Means you can peruse when you have time.

As for bubbles in blanks, was that not the problem Hardy had with the original Angel Salmon rods?

Have a read of the webpage I sent..it probably explains this better than I did.

Thanks again, and indeed, back to work

[David Norwich]

Hi Rob,

Thanks for the link,  I was aware of the information. http://www.century.gb.com/technology.php I'll stick with my response I made regarding autoclaving not being used for making rods in post #16. 

As for the reasoning behind Hardy Angel rods breaking being bubbles in the wall of the blank?  Where did you hear that one?
I worked with Hardy as a consultant for some time on rod design. They may have had breakage issues with certain models. Every company has had issues of one type or another with a design in an attempt at getting the final production model totally user proof. It is inevitable that a volume manufacturer such as Hardy will have a proportion of breakages. I would be certain though, that any breakages on Hardy Angel rods have nothing to do with mysterious air bubbles in the wall of the carbon blank. It just does not happen in the process of making a blank, that bubbles can form or get trapped within the blank wall during the manufacturing process.



Regards,

David.

[Matt Henderson]

okay I'm convinced of the benefits of finding the spline and will take Davids word for it that the spline goes on the same side as the rings.  However I have a question about finding the spline.  I put the thick end of the section on a hard surface, the thin end on my open palm and then with the other hand roll it until I can find the spline.  However I typically feel a resistance to turning and then a jump as it turns.  Do I mark it where I find the resistance or the jump if you see what I'm saying?

Thanks

Matt

[Rob Brownfield]

Heehee..the joys of spines/splines

Its harder to write than view how to do it....so have a look at this..explaines it well ..although he also talks about the "belly" of the rod as well  



You will find there are two areas where the rod bends easier..and two were it jumps. Of the two "easy" ones, one will be very slightly softer than the other..only just mind. You want the rings on the "inside" of this bend...or as he calls it..the belly

Hope that helps.

[Dave Olley]

It should be noted that not everyone agrees with the importance of spine.
It surprises me that so many people say finding it is of utmost importance but can't agree on where to put the guides in relation to it. Some say on it, some say 180' to it and others say at 90' to it. Can they all be correct?
Many people, including many major rod manufacturers say it doesn't make any difference, This is what Dr Steve Harrison of Harrison blanks says about it

"Spines.

Ok, back to spines, excuse the pun.......... First, what is the spine?

Rod blanks are made by rolling a pattern around a mandrel. Like a swiss roll, there is a start and an end to the "roll" and they can produce a hard and soft side to the blank. That is, if you roll the blank whist slightly bent, there can be a feeling of almost a bump in stiffness in one part of the blank. If you hold the tip in one hand and twist with the other, whilst keeping the rod bent, you are most likely to feel this. Holding the rod tip against a wall or floor whilst rolling the rod will do the same. Often the spine coincides with a slight bend in the blank, as ths spine tends to pull a slight curve during the cure. Many builders would say find the stiffest side of the blank, mark it and put the rings in relation to it. But they dont agree where! Some say at 180 degrees to the spine, some say at 90. One going for the stiffest plane, one for the preffered plane of bending. There are arguments for both. I have listened to all the arguments, spent more time thinking about them than most, and I feel I have as good knowledge of the subject as anyone, but I cannot offer you a simple answer. But I do say the following, and this I know is right. Instead of twisting the flexed rod bent over a hand or some other artificial fulcrum, you hold the rod at the handle end, with a weight hanging from the other. That is you load the rod at the tip and hold it at the butt like you do when fishing. Now roll the rod through 360 degrees, and voila, the sensation of the spine has disappeared. Yes, if you do this in a special jig you will detect a tiny variation in the apparent test curve due to a spine, but it is so small you will not detect it in real life. The spine as many rod builders detect it is an artefact of an artificial test. But like a lot of rodbuilding questions, there are no strightforward answers, so talk to someone else about the spine. However, if you want my advice, for what it is worth! Put the blank together and rotate and adjust the sections until the rod is as straight as possible, any natural curve in the rod bending upwards, then place the rings on the underside."

Rod manufacturers such as Sage and Winston follow the above advice. I find it hard to believe that these manufacturers don't know about spine and given the work that goes into making the rods can it be that they just cant be bothered to spend 30 seconds checking for the spine. No, I am sure they think that it doesn't matter.
Lastly Tom Kirkman, top American custom rod builder, writer of many books on the subject and owner / editor of rod builder magazine has also stated that spine makes no real difference and that you should build on the straightest axis.
Tin hat donned
Over to you

[Mike Barrio]

Hi Dave

A tin hat is a good start, but you may like to try a flack jacket    

It is good that we have so many different ideas on this sort of topic, it keeps the hobby interesting.

Best wishes
Mike

[Rob Brownfield]

Rod manufacturers such as Sage and Winston follow the above advice. I find it hard to believe that these manufacturers don't know about spine and given the work that goes into making the rods can it be that they just cant be bothered to spend 30 seconds checking for the spine. No, I am sure they think that it doesn't matter.
Lastly Tom Kirkman, top American custom rod builder, writer of many books on the subject and owner / editor of rod builder magazine has also stated that spine makes no real difference and that you should build on the straightest axis.

I mentioned the above in one of my posts. When a customer picks up a rod, what is one of the first things they do? They look along the rod to see if its straight. As Joe Public, if I am spending £400+ on a rod, I want a straight one

If you spend a little time on the US custom forums you will see that many builders build the rod on the straightest plaine for the same reason.

However, this brings the question of the rod sections twisting against each other if the spline/spines are not aligned. Sometimes you hear of anglers who have rods that for some reason, the tips seem to work loose. Many builders put this down to the blank having been built for straightness, not spine.

[David Norwich]

okay I'm convinced of the benefits of finding the spline and will take Davids word for it that the spline goes on the same side as the rings.  However I have a question about finding the spline.  I put the thick end of the section on a hard surface, the thin end on my open palm and then with the other hand roll it until I can find the spline.  However I typically feel a resistance to turning and then a jump as it turns.  Do I mark it where I find the resistance or the jump if you see what I'm saying?

Thanks

Matt

Sorry for the late reply to your post Matt, I didn't mark this thread for a follow up.

The preferred planes of bending are not an artificial artifact of a test procedure as Steve Harrison states. The guides themselves take the place of the hand or artificial test in actual use.

I never actually refer to where the guides should be placed as the "spine." I always refer to it as the preferred plane of bending. In your example that is the plane it automatically turns to, the jump side,  when you bend the blank. The guides should be placed on the outside of that bend. That is the side away from the hand that you are using to bend it.

Using your body as an example, you can bend forward easier than you can bend from side to side, or bend backwards. If your body is the blank, the preferred plane of bending is when you bend forwards. The rings should then go down your back. As I have said previously, If you line up all the preferred planes of bending in each section - particularly beneficial and important on a multi-section fly rod, the rod will track true on the forward and back casts. If you make a clean overhead cast with the rod built this way, It can't do other than track true, you have made the blank totally passive in the way it bends. None of the sections have a bending conflict with the section adjacent to it.


Regards,

David.