See accompanying photos under, “Grips, Handles and Reel Seats”, “CARL Ferrules”.
A number of months ago, I mentioned developing a composite (FG)ferrule system and was disappointed with the lack of interest, if not simply, “Why?”, so I just let it go. After re-mentioning the concept on Doug Moore’s post, “Ferrules” a few days ago, a few showed interest, so I have prepared a build procedure for those interested or in the need. While the “Tip-over-butt” design is widely used and accepted, by myself included, there are times when the luxury does not exist, as with converting a single-piece vintage FG blank to multi-section rod.
Most would agree a multi-piece rod loses some of its flex characteristics compared to its single-piece equivalent. But transportation and storage can dictate we make a compromise. There are three common methods of joining multi-piece rod sections together; A.) “Tip-over-butt”, B.) External ferrule, or C.) Internal “spigot” ferrule. All adversely affect the natural flex of the rod to some degree, some more so than others. Unsatisfied with accepting the status quoi in favor of designing a system which would be more flexible, lighter and tougher, I utilized my composite fabrication knowledge and habitual over-thinking to produce, D.) CARL, the “Continuous Arc Rod Link”, a lightweight, tough, tubular FG ferrule system.
A.) Virtually all rod manufacturers presently employ the “Tip-Over-Butt” method for joining rod pieces together where the butt section is inserted into the tip section. While widely accepted as the best of the three common ferrules, there are those, myself included, who believe the spigot may afford better flex qualities. While the method requires two separate mandrels to produce one rod, the manufacturers eliminate the cost of an additional ferrule and the time and labor to install it. Additionally, the finished rod has a clean, uncluttered appearance. While I am certain there is more involved than meets the eye, the tip section has to be flared to accept the butt section and, when installed, overlaps the butt as much as three inches creating a double thickness in that area of the rod, all of which interfere with the natural flex of the rod. That stiffer, double thickness area exerts a concentrated strain on the rod at both ends of the overlap as well. The tip-over-butt design is also impossible to employ when producing a multiple-piece from a single-piece blank. But for 95% of the people and situations, a tip-over-butt performs extremely well and I will readily employ it unless a different method is required.
B.) External ferrules are readily available and are the easiest, quickest method of joining rod sections. Most are made from chrome plated brass (yuck, I hate chrome!), some are hard-to-locate aluminum, while the really cool, upper end vintage ones were made of a nickel /silver alloy, AKA German silver, although there is actually no elemental silver in the alloy. NS ferrules are still available, but only from a FEW veteran craftsmen who hand draw NS tubing to the required dimensions. While widely available, easy and quick, external ferrules also restrict rod flex the most of the three, are heavy, not to mention obtrusive and the ugliest (except the NS units). Its larger diameter also adds to its already metal stiffness. As with the tip-over-butt, its stiffness concentrates stresses on the blank at the ends of the ferrule. When in need of building a multi-piece from a single-piece or possibly repairing a broken rod, many rod builders conveniently go for the external ferrule.
C.) With the taper, often compound taper, employed in practically all rods, the spigot ferrule can be very difficult and time consuming to produce without expensive, specialized taper grinding equipment most of us rod builders do not have access to. Most of those attempting to produce their own tapered spigot begin with solid FG rod stock that is sanded, fitted, sanded, fitted and sanded some more. It is very difficult to obtain a consistent, precise taper which is imperative, both in keeping the pieces together while fishing and, more importantly, to avoid producing stress points in the rod which promotes splitting, fracture or failure. Some attempt to utilize a section of a sacrificial rod but one could go through 25 rods before finding one with an only adequately similar taper. I have built a four-piece, 8ft, ultralight pack rod from a vintage FG blank using pieces from an identical blank to produce the spigots, but trust the additional durability and performance of CARL much more. Precisely produced, the spigot may affect the natural flex of the rod the least of the three by securing both rod pieces equally and being inherently more flexible due to its smaller diameter. But its smaller diameter also makes it more fragile and prone to breakage, especially during rod flex when all the stress is concentrated midpoint of the connection. Similar to the tip-over-butt, the spigot design also leaves a clean appearance on the rod.
D.) Allow me to introduce you to CARL, the Continuous Arc Rod Link system. While perfecting the fabrication process of tubular FG external and spigot ferrules, I wondered how they might perform together. The result was immediately obvious. The two work in conjunction with each other, along with the rod itself, to not only allow the rod to flex, but actually encourage the rod to continue its natural flex curve to the very tips where cut and through the connection. The, basically, 45* orientation of the fibers is well suited to produce the proper stiffness and hoop strength without affording an excessive amount. Additionally, decorative thread wraps on the external ferrule can actually be designed to afford increased hoop strength only at the ends and center where needed. Literal side-by-side comparisons with three other identical blanks, butts held identically, horizontal, with a single weight pulling two blanks simultaneously revealed a difference in the flex curve to be less than 0.125in over 6.5 ft, in one comparison, zero difference.
Length and wall thickness were adjusted so that the external ferrule is 0.5in longer with a 0.012in wall thickness while the shorter spigot has a 0.025 wall thickness, for a <8lb rod. The difference in lengths affords distribution any stresses over a larger area while the inherently stiffer, due to its larger diameter, external ferrule is thinner than the easier to flex, thicker spigot. With their inherently identical tapers, the ferrules and rod form a very positive connection, similar to a Morse taper utilized in machinery. While NOT INTENDED TO BE BONDED to the rod to further reduce interference with rod flex, a quick, yet firm tug on either will seat it properly to the rod as needed. Weight of the inner and outer FG ferrules combined is less than 2g while a typical aluminum ferrule is 9g, a weight savings of more than 75%, especially advantageous considering its location half-way up the rod.
Flexing any structure, tubular in this case, results in the outside subjected to tension while the inside compresses, causing the round tube to oval or flatten. The further the tube is flexed, the more it flattens resulting in less vertical surface to resist the flexing until it bends, kinks or breaks. That is why tubing benders confine the sides from pushing outward. CARLs external and spigot ferrules work in union with each other and the rod itself to control this deformation. It could be considered the inverse of the “composite sandwich” process which utilizes a very lightweight core of foam, balsa wood, Nomex honeycomb or such which is skinned with CF, FG or such to produce an incredibly stiff yet extremely lightweight structure. CARL employs the theory inversely by utilizing flexible skins (the ferrules) to control the rigid core (the rod).The result is a tougher connection while encouraging the rod to flex naturally through the connection, all with minimal weight. While CF ferrules could be used for CF rods, CARL typically utilizes E-glass woven sleeves rather than S-glass, CF, Aramid or other composite fabrics, blends or hybrids as its properties are best suited for most rods.
The blank itself is utilized as a mold or “buck” to produce CARLs external and spigot ferrules with inherently and automatically identical tapers. If any steps or bumps are noticed on the blank, avoid those locations for the ferrule. The external ferrule is produced first by marking the blank where it will be cut then spiral wrapped with a continuous length of 0.5in wide household cellophane, overlapped 0.25in, extending at least 2in beyond the ends of the FG sleeves, to insulate it from the epoxy. A rod wrapper helps immensely for this. Care must be taken to minimize if not eliminate wrinkles. This might be the most frustrating operation of the entire process. A couple coats of mold release wax, or even automotive wax on the blank will greatly assist removing the cured ferrule from the blank later. Do NOT attempt to skip wrapping with cellophane as there is too much porosity in the surface of the blank for even numerous coats of the best mold release to allow the ferrule to be removed. Dial calipers are used to measure the diameter of the blank, including the cellophane, at the LARGER END, 1-2in from where the woven FG sleeve will end. A “removal washer” is made with a hole of the same or minimally larger size drilled in a 2 X 2 X 0.125in piece of aluminum and slid onto the blank to serve as a perch to be used later for removal of the ferrule from the blank after cured. Cut the FG sleeves a minimum of 2in longer than needed (6-8in). With the thickness of the cellophane on such a slight taper, the ferrule will end up moving down toward the butt a bit when positioned later without the cellophane. One FG sleeve is slid on, offset from cut mark on the rod slightly toward the tip and wet-out with composite laminating epoxy using the dabbing motion of a 1in cheapie, disposable brush. There is no need to wet-out the entire sleeve(s), in fact may be better to leave the outer 0.5in of the edges dry as long as the sleeves were initially cut long enough. It is then tightly and SLOWLY spiral wrapped with a continuous strip of 0.5.in wide perforated release film to compress the fibers and to allow excess epoxy and entrapped air to be squeezed out, then left to cure. Again, a wrapper is a blessing for this. Typical 1.5 to 2 mil clear plastic sheeting can be substituted with adequate results. Alternatively, composite specific shrink tubing can be used but adds to the cost and I personally find it difficult to use. After curing, the blank is positioned between the open jaws of a vice with the aluminum removal washer against the jaws and a quick yet firm tug on the blank will release the new FG ferrule from the blank, then trimmed and sanded. Before cutting the blank, position the ferrule tightly in place and adjust the previous cut mark if required. At this point, making a second, spare ferrule is a good idea as attempting to duplicate one after the blank is cut is much more difficult and time consuming than fabricating an additional one.
The blank must be cut prior to fabricating the spigot ferrule. The same basic procedures apply to producing the spigot but the location used to fabricate it is moved up the blank to accommodate and adjust for the difference in the blank ID and OD. The tip of the top section is inverted and slid into the top of the butt section until it stops, marked and measured. Knowing my FG sleeves are 0.012-0.013in thick, and the spigot will be two plies thick, producing a 0.025 wall thickness or 0.050 larger OD, I subtract 0.050 from the diameter at the mark and put a new mark up the blank at the corresponding value. This is the new center point for the spigot fabrication. The rest is identical to the external ferrule except two plies or sleeves are used. After the spigot is trimmed, sanded and fitted, an optional 0.5in long semi-rigid foam core (3 to 5lb/ft3 PVC or urethane) is pressed into the spigot and centered where the ends of the rod halves will meet to afford additional crush resistance with virtually no added stiffness or weight.
While not as imperative with the spigot, any cellophane remaining in the external ferrule requires removal. Use a pair of tweezers to grab and pinch the end of the cellophane and continually twist while lightly pulling outward to unwind it from the ID works quite well.
After the ferrules are removed from the blank, allow at least 2-3 days at 75+*F to cure before trimming and sanding. Post curing at =<150*F for 10-12 hours is better yet and the ferrules can be trimmed and sanded without waiting the additional 2 days.
Minimal fitting should be required. With 280-320 grit, lightly sand the OD of the spigot to blend the ridges left by the spiral wrapping. The thinner the plastic used to wrap earlier, the better here. Do not attempt to sand out the weave pattern inherently left on the surface as the pattern will assist insertion, removal, keeping the two sections together while in use and a bit of a cushion for any misalignment. To avoid the, “I cut it twice but it was still too short” syndrome, trim the ends of both ferrules a little at a time until both sections of the rod create a 0.125 to 0.187in typical gap. Snugly installing each ferrule each time, use a pencil to mark the end of both blank sections on each ferrule as a guide. The ends of the blank sections can be sanded, but best to leave this as a final step if needed.
There is the possibility the blank has an internal step near the intended ferrule location which is only discovered after the blank is cut. If such occurs, a longer spigot may be required and/or the spigot may need to be bonded to that section.
The resulting ferrule is translucent, allowing the color of the blank to show through. Pigments may be added to the epoxy if preferred.
Minimum suggested external ferrule lengths / plies (external, spigot);
<8lb rod = 2.75in, (1, 2)
<15lb rod = 3.00in, (1or2, 3)
>15lb rod =? I haven’t been there yet but common sense would prevail.
Admittedly, there are only three CARL equipped rods out there, two for customers and one for myself. I have less than 150 fishing hours on mine, but it has performed flawlessly, enjoyably and, at the risk of sounding boastful, has been happily stressed quite a bit.

Although it may seem rather involved, time consuming and costly, none are actually the case, even for a cheap, perfectionist bastard like me. Although an extra day is needed to allow the epoxy of the first, external one to cure, each ferrule requires approximately an hour to fabricate, trim and fit, three 9in lengths of FG sleeving is less than a buck, and the epoxy and two application brushes might be $5.00.
It is all worth the time, effort and mega-bucks. CARL is much lighter than a typical, commonly used external ferrule while certainly no heavier than the other two, is ultimately tougher than all of the other three, and, most importantly, adversely affects the natural flex curve of the rod less than any of the others. While we all love win-win situations, CARL is a win-win-win!


Material Suppliers:
Soller Composites sollercomposites.com
Composite sleeves (FG, CF, Aramid, blends, hybrids) laminating epoxy, shrink tubing. A+ supplier
PTM&W Industries ptm-w.com
“Aeropoxy” structural epoxy. THE best and only structural epoxy I use. A+ supplier

Mark Talmo
FISHING IS NOT AN ESCAPE FROM LIFE BUT RATHER A DEEPER IMMERSION INTO IT!!! BUILDING YOUR OWN SIMPLY ENHANCES THE EXPERIENCE.

Looks like something you could possibly get put in rod maker!

Double post



Edited 1 time(s). Last edit at 02/26/2017 11:58PM by Trace Butkovich.

I agree that this would make an outstanding article for RODMAKER. Thanks for outlining the process here but it would get more exposure and interest with a magazine article (with photos).

thanks mark...i,m sure you put in a lot of time to develope these ferrules it had to be very rewarding to see it work out so nicely...again thanks for sharing..i do agree, it would fit in the magazine very well.

hi mark..i,m sure your aware that the biggest problem with ferrules is how well do they wear over time...does the inner ferrule wear at the same rate as the outer, etc....or maybe they don,t wear at all, then you would really have something there, lol...just wondering..thanks.

To those responding,
You are welcome and thank you as well. I am flattered.
It is understood and obvious there is not as much need for ferrules these days, but, none the less, the possibility and need can arise. While most rod builders in need of making a multi-section rod simply order one with a tip-over-butt ferrule, I do not have the same luxury of ordering a 50 year old, vintage blank. And I certainly do not anticipate or expect builders to abandon the tip-over-butt design in favor of spending two hours making their own or even spending the additional <$10.00. Even though I am confident CARL is ultimately a better method, the tip-over-butt design has been around for a long time, works very well and I use it as well. Most people already choke when informed how much a custom rod costs, let alone adding an additional $60.00 for a ferrule.
Ben, you brought up a good point / question. While I consider the “…biggest problem” of a ferrule is limiting its effect on the natural flex curve of the blank, wear is also an issue, whether a ferrule, tires on your car, or the living room carpet. With less than 150 fishing hours on my CARL equipped rod, I cannot offer a precise answer. I will offer that it shouldn’t be any less than the prevalent tip-over-butt, spigot, or possibly chrome plated brass ferrules. I will admit that a high quality (and high dollar) hand drawn nickel/silver ferrule just might out wear any of the others, CARL included. The NS alloy was developed specifically for resistance to friction and galling to itself and performs extremely well in that aspect.
To be honest, I am not too concerned with the ware factor of CARL. Due to the fact CARL’s inner and outer ferrules are not bonded to the rod, the spigot can be popped out and given a thin coat of laminating epoxy or PG or both ends of the rod can be ground down slightly. That cannot be performed with any of the others.

Mark Talmo
FISHING IS NOT AN ESCAPE FROM LIFE BUT RATHER A DEEPER IMMERSION INTO IT!!! BUILDING YOUR OWN SIMPLY ENHANCES THE EXPERIENCE.

Mark,

I've been turning your design over in my head for a day now and I think it's neat, but I just can't see how your design is an improvement over existing ferrule designs. I'm hoping you don't take that the wrong way and that you can maybe show me what I'm missing.

You seem to be mostly working with vintage fiberglass blanks, which I also enjoy working on. Aside from the metal ferrule (which I think we both can agree has weaknesses in weight and flexibility) there are two prevalent ferrule types you see on these blanks - oversleeve ferrules and spigot ferrules. Your method seems to combine the two types - it's both a spigot and an oversleeve. In my mind it's increasing the length of the ferrule, meaning that the section where multiple layers of fiberglass are built up causing a stiffer section is larger than it would be with one or the other method. Or am I missing something?

I'm not saying this to be overly critical, but I love simplicity in design, and I feel like your method is adding complication without benefit.

Please set me straight if I'm misunderstanding something.

Tom,
I may not be the smartest man in the world, but like to associate with and learn from those who just might be. This forum is a great place for many things, that included. I appreciate your concern with, not only the design, but offending me as well. Rest assured I take no offence and appreciate anyone who would take the time to ponder and offer feedback.
Your point is a valid one. It is difficult to convey how something looks, let alone how it works in text. I will attempt to rephrase or redecsribe four related points made in the original post: 1.) Tubing deformation; 2.) Composite sandwich; 3.) CARL wall thickness; 4.) Not bonded. Consider rereading the original before proceeding to hopefully assist achieving a better understanding.
You are correct; CARL is a combination of both an “Oversleeve” and spigot ferrule. Most spigots are solid where as CARL’s is tubular. While CARL may not be the first to employ both simultaneously, typical ferrules are either external or internal.
1.) When a tubular structure is flexed, it ovals or flattens. When cut and held at those ends, or the original ends for that matter, the ovaling is greatly exaggerated at the cut where there is more concentrated leverage as well as no material extending further to help resist the deformation. The more it ovals, the weaker it becomes, flexes more especially at the tips, exerts excessive stress on a single-piece ferrule, all causing the original flex curve to change.
2.) While there is obviously a vast difference in the mechanical properties between a tubular structure and a flat one, allow me this basic comparison to describe the interrelated function of CARL’s external and spigot ferrules along with the rod itself. As a structure is flexed, the outer surface exposed to tension while the inner surface is subjected to compression. (I have often wondered if that means the precise center actually experiences zero stress) A composite sandwich is comprised of two fabric skins, we’ll say rigid, bonded to a lightweight core, we’ll say flexible. The resulting structure is incredibly rigid while extremely lightweight. Increasing the thickness of the core exponentially increases the rigidity while adding very little weight. This is all due to the tension exerted on the outer skin being counter by the opposing compression exerted on the inner skin.
CARL utilizes the theory inversely by allowing the flexible ferrules to control and assist the natural flex curve of the rigid blank by equalizing the deformation around the tips where cut. The ovaling encountered in the blank’s tubular shape is similarly controlled by CARL. The result is CARL limits the rods tendency to deform and give-up at the tips and consequently change its natural flex curve rather than controlling the deformation and encouraging the blank to continue its natural flex curve all the way to the very tips and through the joint.
3.) Consideration is calculated into the wall thickness of CARL, including the wall thickness and composite material of the blank. Typically, E-glass biaxial woven sleeves are incorporated due to its modulus of elasticity being lower or equal to that of most blanks. The smaller diameter, easier to flex spigot is typically thicker than the larger diameter external ferrule in an attempt to equalize their effect on the blank, remain flexible, and yet control the deformation of the blank. For a <8lb FG rod with a 0.040in wall thickness at the joint, the external ferrule is a single ply, 0.012in with the 2-ply spigot being 0.025in. The outer ferrule is designed 0.5in longer than the spigot to distribute generated forces over a larger area of the blank. It is difficult to find FG sleeves less than 0.012in thick without special ordering which would be cost prohibitive even though it would be advantageous to be able to fine-tune CARL’s qualities even further.
4.) Due to utilizing the blank itself to fabricate CARL, the interior and external ferrules inherently posses the identical taper of the blank. While important in and of itself, it also allows the ferules to be snuggly fit to the rod without bonding. This also limits CARL interference with the natural flex curve of the rod. Going back to flexing a structure, as the outer surface is put under tension, it stretches and inversely the inner surface under compression contracts. Allowing the rod to move a few tenths (0.0004in) within the ferrules is much better than restricting any movement.
I hope this shed some light on your questions. The most “complicated” part is trying to describe the theory and process. Once experiencing CARL’s attributes, the “benefits” are obvious. The benefits are no smaller than that of the use of micro guides! I will admit this could be considered splitting hairs, but then so is trying to shave 10g off a rod.
We should all be thankful for the tip-over-butt design. It works well, leaves a clean appearance on the rod and is widely accepted. I certainly would not cut one out and install a CARL. But given the need, CARL performs better than any other option when confronted with making a multi-section from a single-piece blank.
I am presently rebuilding a vintage FG Conolon surf rod which is in need of a new ferrule. I was able to readily purchase the odd-ball size from Mud Hole for less than $6.00, but after receiving and inspecting it, I decided this rod deserved a better, higher quality unit. I have absolutely no complaints with Mud Hole as the price was inexpensively more than reasonable, I just wanted something better. The build is on hold and will be until late April, early May as I wait for a nickel/silver ferrule to be fabricated. Cost? A mere $125.00.

Mark Talmo
FISHING IS NOT AN ESCAPE FROM LIFE BUT RATHER A DEEPER IMMERSION INTO IT!!! BUILDING YOUR OWN SIMPLY ENHANCES THE EXPERIENCE.

hi mark, this stuff is interesting..just one question..why not just double the wall thickness of the outer sleeve and omit the inner spigot all together or would it too much heavier.. thanks for all your work.

Mark,

It sounds like a large part of your design is aimed at eliminating the distortion of the rod blank, the ovaling effect you mention. I agree that you'll see ovaling exaggerated at the end of a tube, but I question whether you would actually see it in a well fitting spigot or oversleeve ferrule.

A solid spigot fit to the taper and epoxied into position should prevent the butt section from ovaling, whereas a tubular spigot will allow ovaling. I would think that a tightly fit tip section would also be prevented from ovaling by a solid spigot.

An oversleeve ferrule in itself would not prevent ovaling, but I have seen a number designed with a metal ring embedded into the open end of the ferrule, which would function to keep the ferrule and blank from distorting during flexing.

As you state, I don't think that it would be worth cutting off an existing ferrule to fit your system, but it might be a good solution for some of the older blanks which may not of had decent ferrules fit from the factory.

Ben,
Then a cheap rigid metal ferrule from yesteryear is sufficient. CARL’s flexible external and spigot ferrules perform together with the blank to allow it to flex naturally while controlling the excessive ovaling at the ends of the blank which alters and hinders the natural flexing (inverse composite sandwich).

Tom,
Considering your paragraph #1; You are correct; A solid spigot or stout enough external ferrule by themselves, let alone together, would confine the ovaling. But the cost is excessive stiffness which would produce inherent produce flat spots in the natural flex curve of the blank.
Paragraph #2; I am certain everyone in the rod build community, myself included, would be very interested and would benefit from learning of your method to fabricate a spigot with an identical, matching taper of the blank, whether easy, quick, or not. Again, you are correct as a “solid spigot fit to the taper” should prevent the butt section from ovaling. The flat spot in the natural flex curve it would create would only be enhanced by bonding it into the blank. Similar effect with tip section but less pronounced flat spot due to no bonding.
Paragraph #3; Excuse me for being confused. You state, “An oversleeve ferrule in itself would not prevent ovaling…” yet in paragraph #1 you seem to contradict yourself by stating,”I agree you’ll see ovaling exaggerated at the end of a tube, but I question whether you would actually see it in a well fitting spigot or oversleeve”. Allow me to suggest that you would be happier using the ferrule designs with the embedded ring you mentioned even if, from your description and earlier comments, the ring is in the wrong place.
Your comments seem to be focused on how an external or spigot ferrule functions by themselves. I apologize if unable to convey the concept of how the two can perform together and in conjunction with the blank itself in an understandable fashion.

Mark Talmo
FISHING IS NOT AN ESCAPE FROM LIFE BUT RATHER A DEEPER IMMERSION INTO IT!!! BUILDING YOUR OWN SIMPLY ENHANCES THE EXPERIENCE.

Mark,

I think I've got it now - just took me a bit to sort it out in my head. You're trying to reduce the distortion that the blank is going to undergo while bent (ovaling), while keeping the blank flexible through the joint. A solid spigot or a heavy enough oversleeve will cause increase stiffness, you've created a lightweight spigot and a lightweight sleeve that still reduce distortion but with less stiffness and weight.

As far as matching tapers, most of my work in that sense has been repair to ill-fitting spigots. I use a method similar to a method used by machinists of old (it's a bit of a dying art) called scraping, which is used to create perfectly flat mating and sliding surfaces on machinery. In scraping a very thin layer of bluing agent is rolled onto a known flat surface (such as a granite plate or previously scraped cast iron plate) and the mating surface is set on the plate. The piece is then picked of the plate, and the bluing agent highlights any high points on the surface. These high points are then removed using a scraper, a tool which scrapes off a very small amount of material. This process is repeated until the desired level of flatness is achieved. By removing just the high points you gradually flatten out the surface. With trying to match a taper I take a pencil and rub a thin coat of graphite on the spigot. Then carefully install the tip section (just until it fits, not forced on), rotate it 90 degrees, and carefully remove. Anywhere graphite is removed is a high point - sand it down a bit. Repeat the process until you achieve a good fit. Will it ever be perfect? No, but it will be close enough that the tip can self-lock on the taper without a lot of force.

hi mark and tom s., im i getting closer to understanding these ferrules by thinking that when a fishing rod is flexed you have forces stretching and compressing the rod on the outside surface and as well on the inside surface of tthe rod so it makes more sense to use a thin tube or sleeve on the outside and another thin tube or sleeve on the inside of the rod to transmit bending forces smoothly from tip section to butt section....you have two sets of forces to control , those on the outside and those on the inside surface.. no?

Ben,
You are basically correct.

Mark Talmo
FISHING IS NOT AN ESCAPE FROM LIFE BUT RATHER A DEEPER IMMERSION INTO IT!!! BUILDING YOUR OWN SIMPLY ENHANCES THE EXPERIENCE.

Disappointed with my ability to precisely describe how and why CARL works to a few, possibly all, I woke up at 3:30AM with possibly a better, and hopefully briefer, explanation. Due to the “Inverse composite sandwich” theory described earlier, CARL’s external and spigot ferrules do not need to be as individually rigid and/or strong as a typical external or spigot ferrule which is used alone. This allows CARL’s ferrules to not only minimize disturbing the natural flex curve of the blank, but still controls the deformation or ovaling at the ends where cut which allows the blank to “give-up” and additionally disturb the natural flex curve of the blank. CARL controls the ovaling from both sides of the blank’s wall which allows the external and spigot ferrules to be thinner, lighter and more flexible.
But, to each his own. For those who disagree, disbelieve or doubt, continue using a metal external ferrule or take the time to attempt making your own spigot ferrule with only a somewhat similar taper. At least I have afforded a method of fabricating ferrules with an inherently identical taper to the blank being used.

Mark Talmo
FISHING IS NOT AN ESCAPE FROM LIFE BUT RATHER A DEEPER IMMERSION INTO IT!!! BUILDING YOUR OWN SIMPLY ENHANCES THE EXPERIENCE.

Mark, thank you very much for sharing your design and methods. It appears to be a very nice system with great potential. I also think it would work well for repairing broken rods to help maintain flexibility. Even though I have a large stash of broken rods that can be used as potential ferrule material, it can be difficult to find pieces with the proper taper and modulus which will maintain a smooth curve when flexed. With your method one could temporarily join the broken pieces together with an internal plug (spigot) which does not need to perfect, just something to hold the two pieces together. This will allow the blank to be used as a mold for the external ferrule. The spigot would be made as you outlined, with everything glued in place. This should give a nice low profile splice that maintains flexibility.
Norm

Tom,
Where were you when I needed you? Your description is very good,,, and briefer.
Having limited exposure to the scraping you described, I have only seen it on the tables of rather old milling machines or the ways of old lathes. It is my understanding the scraping additionally affords the lubricating oil to remain on the ways of the lathe longer/better. Additionally, it looks beautiful. Unfortunately, as you mention, it is a dying art due to the pathetically precise milling and grinding machines of today.
Prior to designing CARL, I was initially looking for a business or person who sold FG ferrules. Through my ferrule research, I discovered, a few times, the “graphite-sandpaper” method you described to fabricate solid FG spigots. It seemed to be very labor intensive to achieve the precise taper required . At the risk of sounding rude but to be honest, that is what initiated me to employ my composite and mold knowledge to fabricate my own ferrules. At first, I wasn’t sure which would ultimately be used, the external or spigot, as both had benefits and weaknesses. It wasn’t until experimenting with both simultaneously I discovered the weakness of each being countered and overwhelmed by the benefits.

Mark Talmo
FISHING IS NOT AN ESCAPE FROM LIFE BUT RATHER A DEEPER IMMERSION INTO IT!!! BUILDING YOUR OWN SIMPLY ENHANCES THE EXPERIENCE.

Norman,
I am flattered a respected veteran as you approves. As you mentioned, utilizing CARL to repair a broken rod would work extremely well and, additionally, even if not bonded to the blank. Then one would have an additional rod section to loose in the hold of the boat. lol

Mark Talmo
FISHING IS NOT AN ESCAPE FROM LIFE BUT RATHER A DEEPER IMMERSION INTO IT!!! BUILDING YOUR OWN SIMPLY ENHANCES THE EXPERIENCE.

As a very new subscriber, I just want to add my $0.02 of appreciation for this thread. I'm trying to add a second section to an old Fenwick worm rod I built for my brother in 1973. He broke about a foot off the tip and it was lost. The rod has been sitting in the rebuild/spare parts bin for over 30 years. This method may just be the ticket. However, I have one issue that has held me back from progress. The butt end of the blank is sealed off, and I can't slide a tapered spigot in. Best option - tip over butt ferrule. I don't care if I have to make it into a one piece rod. So, once spigot and ferrule are in place, I'll wrap it and coat it.

I'll reread all of the the above, but any ideas would be appreciated,

Joe Parker