The quality of the guides has improved and that's pretty important. QC tends to be better now - but I have come across big differences in blanks that were supposed to be the same both in new and old production. I also think rod design has evolved and that the range of actions available now is probably broader. Possibly better prepregs allow for lighter longer rods to be built today. I would also say that craftsmanship and finish have improved but maybe the work of Russ Peak challenges that statement.

Does that mean whether any single rod is new or old can determine if it is good or bad or anything else about it?

I don't really think so. So maybe new rods have technical improvements incorporated in some details but it's very hard to say if and how they might be better as an instrument for fishing (note that I didn't say "tool" ).

In general, at least when it comes to trout rods, subjective attributes like action, feel and even looks tend to trump objective measures of performance so it's not even easy to know what better is beyond a pretty basic level of assessment.

Here’s a good example of what was offered in 1979 in England at least:

https://fiberglassflyrodders.com/forum/viewtopic.php?f=3&t=38599

You can see that Hardy only went down to 4wt in their glass line. So few of them come up for sale (and at high prices) that they must not have sold too many.

It’s worth noting that Hardy and others sold lightweight bamboo rods for many many years - the Marvel was introduced in 1922 (I think). I have one from the late 1960’s that is marked 4/5, but there are others out there that are marked 4 and maybe even 3?

When I started fly fishing in the 70’s I think that 6wt was pretty much the “standard” for trout in the west. This has migrated down to the ubiquitous 9’ 5wt over time. My guess is that 4wts used to be considered lightweight specialist rods the way that 2-3wt rods are now.

Leonard Fairy Catskill is rated for G-braid, which is a modern 3-wt, and many describe them as 4-wts.

most innovations are a marketing smoke screen to lure N+1 buyers.
Doubt if you can show any material improvements in glass rods since the 70s, which are notably improved over 1950s (materials and experience working the medium).
Exactly what are these new materials

and you're the one in Missouri. Show me.
Seriously, documentation of improved resin. Even a statement of new, improved resin used in rods.
There's post after post of speculation, without a single statement of fact.

"and you're the one in Missouri. Show me.
Seriously, documentation of improved resin"
I posed the question because of something I've read about Loomis' work and an interview with him in which he mentioned improved resins as though that had been a major advancement in graphite rod design on more than one occasion, so, perhaps the resins used interchange between the two fabrics. As I understand it the early graphite rods only changed the material of the cloth and not the resins nor the technology, but I'm not expert on the subject nor am I especially interested to become one.
My "speculation" is as I posted above "I would guess though, that around 1970-75 that the fiberglass fly rod was at it's zenith, with 30 years of experiments and learning going into most designs at that time, and all that (or most) knowledge lost since then as the old guys passed on and the tooling discarded in favor of the multi section carbon sticks."

Dusty linked to a worthwhile podcast discussion with Jim Bartschi of Scott Fly Rods. At 30:30 Bartschi states, "where there's not a ton of innovation going on the material side, the way to create something new is to innovate with what's out there." By 1980 the major technologies for fiberglass fishing rod production were in place (see the table). US fiberglass fishing rod production then declined to near extinction by the early 90s. In the years since glass made a slow comeback, but there were no major leaps in materials or methods. However, as Jim Bartschi states often in the podcast, rod design and manufacturing are always being refined, with continuous tweaks and improvements (discussion below the table). The podcast is definitely worth a listen.

Notable Glass Tech Milestones - Materials Version

• 1930s - glass fiber production was developed by Owens-Illinois (Owens-Corning PDF historic document - see page 4 of the document).
• 1935 - Borosilicate glass fibers (E-glass) and glass fiber reinforced plastics were developed (see page 6 of the PDF document).
• 1945/1946 - tubular fiberglass fishing rods were first marketed. Early glass fiber composites were based on phenol/formaldehyde (phenolic) and urea/formaldehyde resins. With time the market moved to the NARMCO production method of wrapping a fiberglass cloth impregnated with a binding resin (aka, pre-preg) around a steel mandrel followed by heat curing. Several companies developed high pressure autoclave curing to reduce voids in the phenolic resin (for example; Pacific Laminates, Phillipson, Grizzly/Fenwick, Conolon).
• 1947 - Lynco Grinding Company began commercial mandrel production (everyone bought their mandrels from Lynco).
• Early 60s - Phillipson begins building rods with 3M Scotchply pre-preg (uni-directional fiberglass with epoxy resins - Johnson & Johnson, Fiberglass Fly Rods, 1996). 3M markets Scotchply Type XP-231 "designed specifically for fishing rod manufacture" (3M sales flyer, 1967).
• Early 60s - S-glass was developed for military use. In 1967/68 S2-glass (the 'commercial' version of S-glass) was marketed by Owens-Corning (see Kinsella et. al., Mechanical Properties of Polymeric Composites Reinforced with High Strength Glass Fibers). For 50 years S2-glass has been the highest specification glass fiber on the market.
• 1965 - Fenwick tip over butt ferrule was patented (US Patent 3,186,122).
• 1968 - Jon Tarantino's spigot ferrule was patented (US Patent 3,554,590).
• 1973 - Fenwick and Shakespeare marketed graphite (the various graphite flavors aren't significant here, nor are boron or Carrot Stix).
• 1977 - S2-glass fishing rods are marketed. Fenwick offered Fenglass, a composite with S2-glass axial fibers and E-glass hoop fibers. In 1979 Sage initially sold their S2-glass rods alongside their graphite models. Likewise Lamiglas marketed their S2-glass rods in 1979. Berkley used S2-glass in their Specialist rods (anyone have a catalog for these?). With the exception of the Fenglass Lunkerstix, the market ignored S2-glass in favor of graphite.

On the modern fishing rod market there are two flavors of glass fiber, traditional E-glass and S2-glass. S2-glass is marketed in the US as S2-glass or Zentron (a tradename held by AGY) and as T-glass in Japan. The binding resin is invariably an epoxy, which allows heat curing without high pressure autoclaves. Epoxy chemistry has long been a mature field. While there are many epoxy choices available to a rod designer, the basic effect is the same - the epoxy efficiently holds the fibers in place. A third, very proprietary component is rarely mentioned. Sizing chemicals (see Kinsella et. al., section 3) are applied to the raw glass fibers to improve handling and resin adhesion. The phrase "new resin systems" refers to variations of the same basic chemistries.

Aeronautics, automotive, wind power, and military uses drive the market for stronger, lighter composites. With fiberglass this is done by improving the fiber/resin bond and increasing the amount of fiber with respect to the resin. Increasing the amount of fiber also increases the composite's elastic modulus. Skipping the math for now, a higher modulus composite allows the rod designer to obtain a relatively slender blank, or a thinner walled blank, or a combination of both. For instance, the classic Scotchply XP231 contained 47% fiber volume in the final composite. The Zentron product description indicates fiber volumes of 60%, leading to a 30% modulus increase simply by having a more efficient composite. This 30% increase was not a sudden leap of technology, but more like a bank account earning 0.5% per year. Forty five years of small improvements add up.

Modern rod rolling equipment is designed to handle thin graphite pre-preg materials. I measured two Phillipson six weight Epoxite blanks and the butt section walls were ~0.035". Scotchply XP231 yielded a fiberglass 'ply' 0.009" thick, meaning my rods were produced with only four wraps of material around the mandrel. Glass prepreg now comes as thin as 0.004", which would translate to 9-10 wraps of material for the same wall thickness. Thinner prepreg allows allows the rod designer more flexibility in designing those thinner walled blanks.

On the Swift Fly Fishing website (Epic rods) there is an interesting statement, "Materials may come and go, but fly rods are all about tapers." The materials market has provided years of incremental improvements. In the aggregate these allow a rod designer to pursue new tapers. Whether these tapers are better than, or simply different from, the classics of the 70s is a whole different discussion.


Tom

Great post Tom.

Large arbor fly reels were an innovation?

Hardy Sintrix, 3M Powerlux, and Loop Nanocross are designed to increase graphite composite toughness. The engineering terms strength and modulus are tossed around almost interchangeably in advertising and on web sites, but they are very different. Elastic modulus is like tugging gently on a rubber band - the harder the pull, the more the band stretches. Once the pull is released, the band goes back to the original shape. In terms of fly rod taper design, the elastic modulus makes the rod go. Modulus is a description of composite stretching within the working design range. When a rod bends, the fibers on the outside of the bend stretch (green curve in the image) and the fibers on the inside of the bend compress (red curve in the image). With a higher modulus composite, the green curve can contain less material, for instance a thinner walled rod blank.



Tensile strength is like pulling on the rubber band until it breaks. Strength is a description of composite stretching as the design fails. More important to a rod designer is compressive strength. For fiber reinforced composites, the compressive strength is always less than the tensile strength (see the fifth and sixth lines of the table). That means rod failure will first occur along the red line in the image before the the green line. Graphite composites are more susceptible to compressive failure than glass composites. With Sintrix and the like, nanometer sized particles are added to the same epoxy resins, much like a brick mason would add sand to mortar. The nano-particles somehow reduce the tendency of graphite fibers to buckle during compressive failure, thus increasing the compressive strength.

The nano-particle effect should work for glass fibers, but would be a solution to a much less significant problem. I attended the 2010 ISTD show in Denver - when Hardy released their first series of Sintrix graphite rods. I asked the Hardy rep when they would bring the same technology to their fiberglass rods. He replied that glass was already tough enough. So again, with regards to glass nano-particles are more of an incremental improvement, not a big game changer.


Tom

Yes, the rod cross section becomes oval as the rod bends. Tubular rods must have some hoop fibers to support the cross section. Even rods built with 'uni-directional' materials have hoop fibers. Without them the rod would collapse like a drinking straw.

If a rod builder uses thinner pre-preg, the rod blanks will have more wraps of material on the mandrel. One likely benefit might be a less apparent spine. As far the importance of locating a spine during a build, that's a whole different topic that has been discussed on forum many times.


Tom

Great details in the answer. Thanks!

I’m not particularly a fan, but I do think that the Large Arbor reel is definitely an innovation. It is different from what came before, changes the performance of the reel, and is widely adopted now. An important innovation? Mmmmm... dunno. FWIW, Loop claims they invented it...

https://lowflowfly.com/about-loop/history-of-loop/