Stiffening a noodle of a rod by filling with epoxy

[steelfish]

I think the two major risks would be ruining the balance of the rod by ending up with far too much weight in the butt, and creating a "hinge" point in the blank that increased the chance of breakage.

yep, I couldnt find a correct formula with I wanted to try on a blank

The real solution is to get more rods... and then more reels to go with these rods. And then more rods. Repeat.

I ended up doing that, I call it practicing so, my wife dont get mad compared to saying "Im building another fishing rod for me"   

[jurelometer]

Takek at that chart linked in my previous post.  Unreinforced cured epoxy is brittle and non-flexible. Expect a  result akin to what you would get from fiberglassing over a (silica) glass rod, just not quite as dramatic.

-J

[JasonGotaProblem]

To be clear I'm here asking because I don't have the answers, but if there was good adhesion wouldn't the blank and the epoxy reinforce each other? The blank is very elastic, the epoxy is not very elastic but will bend. So the elasticity of the blank would bring the epoxy back to shape after a bend, and the epoxy would resist the bend. Making it stiffer. Right?

In this case the first of the two is foam filled. So that idea is DOA for that blank. But I'll still consider experimenting with the other.

[jurelometer]

If it is not elastic, but is bending, then it is deforming. Permanent deformation is a destructive act. Can't deform over and over again and expect the material to hold up.

According to the chart, unreinforced epoxy is not elastic.  It probably depends on the type of epoxy on how much it deforms vs. breaks.

But to your point on the effect of the combined blank and solid core:

The ratio of blank wall thickness to hollow core diameter probably matters.  If the walls were huge, but the hollow core was tiny, then filling the core with epoxy would have little effect. But if you have a large diameter blank with thin walls, it would end up a broomstick.

As you get toward the tip of the blank, the ratio  wall to core increases. My guess is if you are able to fill with epoxy from butt to tip completely, you would have a stupidly stiff blank until you got near the tip, at which point it would be able to bend, but since the top section of the rod is now heavy, the extra weight will make for a larger oscillation amplitude (how far the tip swings) and a lower frequency.   Light tips cast nice because they don't have as much inertia that causes the tip to swing back and forth after the cast is released. What we call a damp rod is actually a rod with a light, stiff tip.

But hey, give it a try if you are so inclined. 

[funhog]

a fiend of mine stiffend his outriggers by spiral wrapping them with 1"fiberglass cloth-tape wet-out with resin. a light sanding and gloss coat and they worked perfect.
How about unraveling enough cloth until you have enough fiberglass sting and spiral wrapping the rod. Plenty of Fiberglass Supply places in FL. the even carry carbon fiber, if you want to go that way . Surfboard supply houses carry a wide variety of glass and resins and you can buy in small quantities

[boon]

To be clear I'm here asking because I don't have the answers, but if there was good adhesion wouldn't the blank and the epoxy reinforce each other? The blank is very elastic, the epoxy is not very elastic but will bend. So the elasticity of the blank would bring the epoxy back to shape after a bend, and the epoxy would resist the bend. Making it stiffer. Right?

I think over time the epoxy would get broken down to chunks/crystals/dust, or at least broken into section inside the blank, a bit like a dropped candy-cane.

[Brewcrafter]

As far as affecting the action of the rod, I like the thought of using spray in foam insulation.  But then again, that is a semi-unknown and semi-irreversible.  BUT - I have a potential solution that I guarantee if you try it you will cuss my name.  I have never done this, I am only speaking theoretically here...
Cut a plug to fit into the end of the rod that you can jam in there/glue in.  Then.... get a bag of styrofoam "bean bag pellets" and fill your blank.  When full, compress them with the plug and glue it in.  Lightweight, flexible, and the added benefit of you will find bean bag pellets scattered around your workshop/home for the next 6 months minimum no matter how careful you were. - john
-But I do think it can work 

[jurelometer]

Foams do the the same sort of thing.  Here is a thought experiment.  Take a chunk of the  fiberglass from a surfboard.  Pretty elastic, right?

Now take a foam surfboard blank.  Pretty non-elastic, and breaks pretty easy.

Now encase the foam  surfboard blank with that same thickness of fiberglass.  The resulting surfboard is now very rigid, and relative hard to break, but load it up too much and it will snap in two, similar to how the foam alone would fail.  It just requires more load.

Filling with pure eproxy is sort of like filling with foam, just heavier and a bit harder to break.

So here is a bit of amateur sciencing that roughly explains it (I'm not trained in material science):

Every type of solid material  will have a modulus of elasticity (AKA Young's Modulus).  This is a number that represents the potential for storing energy in a  material that has been elongated or compressed.  The MoE is used to calculate forces required, distance elongated/compressed, etc. 

The higher the MoE value, the more energy can be stored for the the same cross section area. The MoE for polystyrene foam and pure epoxy are both close to zero.  Single layer fiberglass/epoxy composite around 15 gPa, six layer around 400 gPa

In other words, I'm with Boon.  Not sure exactly how and when failure would occur., but until then it will be very stiff.   If you want to increase elastic strength, you want to use something that adds elastic strength, not something with no elasticity.  Just asking for trouble.

As funhog said and as the MoE numbers tell us,  adding layers is the answer, but I suspect that the outcome would not be very exact, plus the effort and expenses is kinda high  to justify  for beefing up an inexpensive rod.

-J

[Cuttyhunker]

I'm with Boon on this one just try using the slow action rod with a lighter drag, let the fish fight the rod and drag.  The fish will take a little more line on the runs but with the braids there should be enough capacity on most smaller reels.  If you want a faster rod just buy, trade, yardsale etc etc.

[Cor]

I won't comment on whether the filling may or may not work.  I once purchased a 10'6" surf blank from American Tackle, but when it arrived I found the but section of the rod too soft and flexible to cast effectively.

My plan was then to make an graphite insert from an old rod piece of around 1 mt long to fit tightly inside the but section and glue it in place with epoxy.

The result was a blank which was a lot heavier and not much stiffer.

What would probably have been a superior solution was to make a sleeve and fit it over the outside of the butt of the rod.

The reason is that the diameter of a blank is critical in determining the amount of flex it has.

I have quite often made ferrules in the same way.    The ferrule has to be made with a section of blank that fits inside the rod on both sides which makes the ferrule piece of much thinner diameter  and significantly weaker and more flexible than the blank.  The only way this can be done is by doubling or even tripling the thickness of the ferule by gluing one or two additional pieces inside.

[Cuttyhunker]

I do have A Penn 10/0 mounted on a quality factory rod that boasts urethane filled, I posted it a few years ago on the "Penn reels as you find them" thread a few years ago, so it has been tried, although I not sure of the reasoning. 

[jurelometer]

I do have A Penn 10/0 mounted on a quality factory rod that boasts urethane filled, I posted it a few years ago on the "Penn reels as you find them" thread a few years ago, so it has been tried, although I not sure of the reasoning. 

Ooh, interesting!

https://alantani.com/index.php/topic,15800.msg423161/topicseen.html#msg423161

A hard foam core would resist ovaling of the blank as it bends, making it stronger. But if the foam is hard, it will also inhibit bending and degrade when repeatedly bent.  If the foam is soft, it will last longer but won't strengthen much.  Maybe a foam core was something that they could get away with on a stiff trolling rod?

-J

[Cor]

Here's an alternative that I actually did myself...

Had a rod I really liked except for the floppiness, but found a way to stiffen it up real nice. I had a blank that happened to slide perfectly into the larger rod. So, I spread epoxy all over it and slid 'er in, gave time to dry, and bingo! The perfect action!

Only negative was of course the resulting rod weighs as much as two rods, but it's not as bad as say a solid glass rod. Worked out great for me. 

I did quite a few similar tricks, usually tried to stiffen the butt section but never had success using an insert.   The insert is to thin and does not provide the stiffness I wanted.    However a sleeve worked far better.   It may not look so nice but it can be hidden under some butt material or with a binding
Weight is always an issue and it adds a lot!

Filling it with some type of material may work, but with epoxy you would need to get product that has some flexibility, most of the stuff dries rock hard.

Maybe you could layer the epoxy on the inside by using your rod dryer and centrifugal force...... 

[CapeFish]

My grandfather's first rod was steel tube it was a 3 piece noodle he inserted bicycle spokes into the tubes to try and stiffen it, I think the rod must have been from the late 1920's, I tried to fish with it once or twice. Seems people have been trying to stiffen rods forever and a day.