Carbon Fiber Rodding

[coolhandchris]

I got a mailer from weha that had carbon fiber rodding in 1/8 x 3/8 size. Claiming it is stronger than fiberglass...

Has anyone tried this stuff?

[Dan Dauchess]

Regent dropped off two 40" pieces just before Christmas. I was going to do a head-to-head against 1/8" x 1/2" cold-rolled steel in the next week or so. I have some leftover regular fiberglass as well. Just got to find the time......

[kdnoel]

Carbon fiber is much stronger than fiberglass.

I just wish they would pre-impregnate it with a water based activator.

How many golfers out there use carbon fiber shafts?

High end bicycles are made of it.

And on and on...

[coolhandchris]

Carbon fiber is much stronger than fiberglass.

I just wish they would pre-impregnate it with a water based activator.

How many golfers out there use carbon fiber shafts?

High end bicycles are made of it.

And on and on...

Yeah, but they want it for the strength to weight ratio. When I am carrying a 3cm 108"x48"L with a 60/40 in the middle, I don't care about the weight of a little rod.

[ronald hannah]

The issue will be if we can get the epoxy to impregnate well enough to mitigate any slip.

The adhesive bonding to the stone and the rod is always the deciding factor. I don't believe, that in any of the SFA's testing, the rod has actually failed. It is always the bond to the rod or the bond to the stone that has failed.

Please correct me if I am wrong.

[coolhandchris]

I thought that the fiberglass rods would shear in two and actually break. I always rough up rods (aside from allthread)

Also, I would like to see how much strength it adds, if any.

I know steel flat bar adds strength, I currently use allthread on problem stones (90% of the time). Sometimes I use flat bar, but only on really bad stuff. I am not sure the allthread adds much strength, but it keeps it together for repairs.

[Dan R.]

DISCLAIMER: I am not a fan of rodding.
Rodding is only for holding it together during handing, correct?
Why wouldn't one use the best (flat stock) on everything? Is it that much more expensive?
The rodding tests I participated in concentrated on the actual pressure to break the stone, not the rod. I do not recall any rodding material actual breaking apart. I would think the rigidity or the rod and the bond of the glue/rod would be the key factors. There seems to be 2 schools of rodding:
#1. merely hold the piece together for the eventual repair, should it break.
#2. add strength so the piece will not break

it would appear to me, that every rodder must define what they expect from the process )#1 or #2) and proceed from there.

[Mark Meriaux]

The individual carbon or glass fibers are only strong in tension, but don't offer much in flexural rigidity until you layer or build them up. The "rod" of fibers will offer some flexural rigidity, but as Ron mentioned, the failure point then is not the rod itself, but the bond between the adhesive and the rod. This has been true in most of the demos that I have witnessed. The rod breaks free from the glue under extreme stress, and that little movement can allow the stone to fail.

[DavidL]

From dealing with Carbon Fiber in marine environments I think you should be able to get enough uneven surface area to get the glue to adhere to. But what about the expense. Carbon Fiber guys like to get paid alot for their materials, would this be any different? I am sure time will tell.

[Matt Lansing]

The plain white fiberglass rods with the smooth exterior would actually shear itself right across the crack in the stone. The sink top would break rod and all.

I would be curious to hear about the carbon fiber rods strength tests.

[Dan Dauchess]

I was thinking about the testing method and came up with this:

40" pieces of 4" ubatuba backsplash with a single rod of each type embedded in acrylic epoxy. (steel, fiberglass, carbon)
Place splash flat across two bricks spaced 36" apart.
Stack samples on center of splash until it cracks and then until it breaks.
Pictures of the process and the aftermath....

Any other refinements?

[Matt Lansing]

That is pretty much what we did at my workshop a few years back.

[kdnoel]

From dealing with Carbon Fiber in marine environments I think you should be able to get enough uneven surface area to get the glue to adhere to. But what about the expense. Carbon Fiber guys like to get paid alot for their materials, would this be any different? I am sure time will tell.

It always has been expensive but maybe that has changed on the raw material side.

[coolhandchris]

It is like 60 cents a foot. The white fiberglass is 50.

[Nick]

First, rodding is stupid.

Second, Chris hit the the most important nail on the head. Whether it is the hood/roof of an exotic sports car, or a photograghy tripod (yeah, I kinda get obsessed with researching new hobbies), the purpose of carbon fiber is NOT neccessarily strength, but the rigidity or strength to weight ratio (as chris said) which serves a very good purpose on a fast car or tripod someone is carrying all day, and (as Chris said) not so much on a 150 lb piece of stone, if the number varies by +/- 2% (and it wouldn't be nearly that much from SS to carbon fiber) it is inconsequental. 55lbs less(and an extra $3000) on an M3 sedan and 2 pounds (and an extra $450) off a 5 pound tripod are instances. I know that Chris is probably looking into Picking up a 2012 Mercedes SL500, and he will be happy to find that his near 100K sports car is having a carbon fiber makover and in addition to the weight loss, the center of gravity of the car is also transfered to a more deep seeded and lower position thus making it probaly handle better.

Third, based on the above examples, carbon fiber is a material that is used for maxuim performance in luxury goods where it is OK to start seeing large diminishing returns as the dollar amount increases alot and the performance does imporve, but much less based on a per dollar standpoint. Other than sounding cool, I have no idea how carbon fiber for rodding has its place in granite. And on top of that, I bet it is absolute garbarge carbon fiber and really may not perform better than other stuff you guys already use.

Fouth, Rodding is stupid. Rodding with carbon fiber is like the Fonz getting a 700 on his SATs.

[Nick]

Chris just posted when I did.

For .10 more than fiberglass it has to be of complete garbage quality. Anyone know how to test it?

[coolhandchris]

Chris just posted when I did.

For .10 more than fiberglass it has to be of complete garbage quality. Anyone know how to test it?

Postby coolhandchris on Thu Dec 30, 2010 7:39 pm

Post by Nick » Fri Dec 31, 2010 6:55 am


Yeah, bro, exactly the same time.
Maybe I hadn't posted and then you wrote your carbon fiber series and posted. Only like a 10hr difference.


I think the carbon fiber could be a good idea, just because there will be strands holding the rod together. Like the old mythical rodding that I hear about, but doesn't exist.

Plus, it will save like 8 grams on a 150kg top.

[Ken Lago]

First, rodding is stupid.

Second, Chris hit the the most important nail on the head. Whether it is the hood/roof of an exotic sports car, or a photograghy tripod (yeah, I kinda get obsessed with researching new hobbies), the purpose of carbon fiber is NOT neccessarily strength, but the rigidity or strength to weight ratio (as chris said) which serves a very good purpose on a fast car or tripod someone is carrying all day, and (as Chris said) not so much on a 150 lb piece of stone, if the number varies by +/- 2% (and it wouldn't be nearly that much from SS to carbon fiber) it is inconsequental. 55lbs less(and an extra $3000) on an M3 sedan and 2 pounds (and an extra $450) off a 5 pound tripod are instances. I know that Chris is probably looking into Picking up a 2012 Mercedes SL500, and he will be happy to find that his near 100K sports car is having a carbon fiber makover and in addition to the weight loss, the center of gravity of the car is also transfered to a more deep seeded and lower position thus making it probaly handle better.

Third, based on the above examples, carbon fiber is a material that is used for maxuim performance in luxury goods where it is OK to start seeing large diminishing returns as the dollar amount increases alot and the performance does imporve, but much less based on a per dollar standpoint. Other than sounding cool, I have no idea how carbon fiber for rodding has its place in granite. And on top of that, I bet it is absolute garbarge carbon fiber and really may not perform better than other stuff you guys already use.

Fouth, Rodding is stupid. Rodding with carbon fiber is like the Fonz getting a 700 on his SATs.

It's mean to say stupid, haven't you heard that? My daughter tells me that all the time.

[Nick]

It is funny when you say something is stupid and then (as Chris pointed out) in doing so you say something much more stupider .

[pkomorowski]

Anyone have a photo of this carbon fibre rod?

[Dan Dauchess]

My samples are out in the truck - will take pictures....

The carbon fibers appear to be applied to the typical fiberglass rods along the skinny edges in order to increase the strength of the rod much like an I-Beam. The rod also has a formed groove on each wide side - perhaps to increase adhesion surface area.

[Dan Dauchess]

A picture.....

Carbon-Fiber Reinforced Rod from Weha.jpg (414.08KiB)Viewed 2018 times

[pkomorowski]

Looks like a fibreglass rod with something glued to it. Doesn't look impressive.

[Dan Dauchess]

I would be suprised if it had significant performance advantages over standard fiberglass.....

[Nick]

But you can tell your customers you use carbon fiber to rod their granite, that has to be worth $50 in cool points and getting the job , maybe??