Carbon weight for blades

[foreright]

Hi all,

I’m 20 or so blades into my building “journey” at this point, the last 10 or so being carbon, ALC and a couple of other fibre attempts. These have been mostly successful - have managed to get a few into the hands of so county and national players for their comments and those have been generally positive which is nice.

One thing though, I’ve discovered that my personal preference is actually for inner carbon and by that I mean actual straight carbon fibre rather than any of the mixes I’ve tried so far. My current main blade uses hinoki, ayous and kiri but is a little in the chonky side at 98g.

On that point I was wondering if any other blade makers could weigh in (haha) with what weight of carbon or fibre they are using in their builds? IIRC my main blade uses 240gsm CF which is probably why it’s a little on the lardy side. For my next build I do have some CF which is 150gsm or so but I’m thinking of experimenting with 90gsm as that would result in a pretty substantial weight saving.

I’ve not been able to find any real information about this anywhere - anyone have an opinion? Ultimately I can’t imagine you really need the strength of the thicker carbon in a table tennis blade and it’s going to be mostly dead weight over a thinner cloth, right?

 

[Archosaurus]

I don't know about blade making, but there's one thing to keep in mind:

For the most part, the blade is a spring in series, so its effective K is determined more by the softest part. Even if you make the carbon 10 times stiffer, it might only result in a relatively small stiffness increase for the actual blade.

IIRC wood is typically something like 8 GPa for the bending modulus, while carbon fiber is typically 70 GPa although of course both highly depend on the direction and so on. Either way it's something to think about.

EDIT: I would like to add that the "for the most part" refers to how the back of the bat surface which isn't hit by the ball isn't receiving a force, so it's not a true spring in series in some ways. It will be different depending what you're looking at. I don't fully understand a lot of it, though.

 

[foreright]

Yes well this is kind of my point - in reality the forces involved in a shot in table tennis are not going to require F1 level composites - my guess is that even the lightest composite cloth is going to achieve the desired effect (whatever that might be…) and that anything thicker is just going to result in dead weight and/or unnecessary stiffness (lol).

it’s worth noting that the modulus of elasticity of wood varies HUGELY - there’s quite a difference between something like balsa (modulus approx 4 gpa) and ironwood or jatoba (modulus >20 gpa). It would not be that difficult to make a blade from say jatoba that has similar stiffness to CF - it would however be thick and very heavy which is the primary advantage of composites - ie. Weight saving.

Regardless I’m going to give this lighter cloth a try and see what happens xD

 

[belllfador]

Hi all,

I’m 20 or so blades into my building “journey” at this point, the last 10 or so being carbon, ALC and a couple of other fibre attempts. These have been mostly successful - have managed to get a few into the hands of so county and national players for their comments and those have been generally positive which is nice.

One thing though, I’ve discovered that my personal preference is actually for inner carbon and by that I mean actual straight carbon fibre rather than any of the mixes I’ve tried so far. My current main blade uses hinoki, ayous and kiri but is a little in the chonky side at 98g.

On that point I was wondering if any other blade makers could weigh in (haha) with what weight of carbon or fibre they are using in their builds? IIRC my main blade uses 240gsm CF which is probably why it’s a little on the lardy side. For my next build I do have some CF which is 150gsm or so but I’m thinking of experimenting with 90gsm as that would result in a pretty substantial weight saving.

I’ve not been able to find any real information about this anywhere - anyone have an opinion? Ultimately I can’t imagine you really need the strength of the thicker carbon in a table tennis blade and it’s going to be mostly dead weight over a thinner cloth, right?

You have 2 carbon layers with area close to pi × 0.076^2=0.0181m^2, or 2× 240x 0.0181=8.7g weight of the carbon. Going to 90gsm will cut this value to 3.3g, or 5.4g lighter blade.

IMO, 90gsm is very thin carbon layer do give you additional speed. Ask @SDC, he uses a lot of types of composite materials.

 

[Archosaurus]

Yes well this is kind of my point - in reality the forces involved in a shot in table tennis are not going to require F1 level composites - my guess is that even the lightest composite cloth is going to achieve the desired effect (whatever that might be…) and that anything thicker is just going to result in dead weight and/or unnecessary stiffness (lol).

it’s worth noting that the modulus of elasticity of wood varies HUGELY - there’s quite a difference between something like balsa (modulus approx 4 gpa) and ironwood or jatoba (modulus >20 gpa). It would not be that difficult to make a blade from say jatoba that has similar stiffness to CF - it would however be thick and very heavy which is the primary advantage of composites - ie. Weight saving.

Regardless I’m going to give this lighter cloth a try and see what happens xD

Yep, that's what I mean. By changing out the wood, you will more effectively influence the final stiffness because you're changing the softest part.

If I had to guess the reason everyone isn't using super thin compositions is because other things also change, maybe very nonlinearly, such as the torsion stiffness and so on. Maybe there's some real downsides to using the lightest viable carbon layer.

 

[lodro]

Yep, that's what I mean. By changing out the wood, you will more effectively influence the final stiffness because you're changing the softest part.

If I had to guess the reason everyone isn't using super thin compositions is because other things also change, maybe very nonlinearly, such as the torsion stiffness and so on. Maybe there's some real downsides to using the lightest viable carbon layer.

Maybe there's some real downsides to using the lightest viable carbon layer.= Maybe, maybe not . After all it depends what one wants to achieve. Lots of blades are now using "soft carbon" which is not woven carbon but more like a very thin felt. 90 gr woven carbon could be ideal. It is very finely woven but of course it is twice the price. I would like a 90gr ALC but can't find any.

 

[foreright]

Yeah the carbon felt is the other option - might give that a go next. As you say, 90gsm cf is expensive but I’m going to give it a go and see what happens - just need some time now to get building xD