Question for Blade-Builders

[Choosikick]

I am always curious to know how much pressure you compress the wood with and with which device. I also suppose that when you put more or less pressure on your wood it affects the characteristics of the blade.

You're right, it also affects the stiffness of the blade. I have two blades with the same wood, glue, structure, thickness, size and weight, but glued together with different pressing forces. So, a blade with less pressing force on the same rubbers feels softer.

 

[latej]

Sorry but this is not correct. A single layer is stiffer than any of the other combinations. If all three layers are oriented vertically then the difference is negligible, but it also depends on the glue used. There is really no benefit for this type of structure unless you are using a different wood for the central layer. However, if the center layer is horizontal, you lose longitudinal stiffness and gain transverse stiffness, so case 1 is stiffer than case 2. Case 2 will feel more homogeneous than 1.

Thank you @hipnotic for dispelling the myths. TBH, I also thought the blade with more layers would be stiffer... E.g. there is the Vodak 4APC King Stiff&Spin, which really feels signif. stiffer than my Vodak Horejsi ALC. Also, a friend of mine (from another club) uses a blade with like 9 or 11 thin layers, and when I tried it, it felt very stiff, it also felt hard and fast, too fast (especially when engaged) for me. I knew the number of layers won't determine softness/hardness, because the Vodak 4APC King still feels soft, but I definitely thought the: more layers => more stiff implication holds. Also I thought that a blade with 1 thick and 2 thin layers will be less stiff than a second blade with the same thickness, made from 3 identically thick layers (all other things being equal). That, I assume now, is wrong too. Cheers.

 

[Choosikick]

To confirm my words, there is also this blade - Donic Epox Topspeed OFF +. It is made only from longitudinal layers of ayus or kiri glued together with epoxy glue. This blade is fast, light and tough.
I think it's hardly possible to play with a single-layer ayus of the same thickness at all.

 

[Choosikick]

Donic Epox TopSpeed

Donic Epox TopSpeed table tennis blade reviews and ratings on Revspin.net.

revspin.net

My blade was also about 7mm thick and weighed around 84 grams, just like the person in the reviews, but was very stiff and fast. Unfortunately, I did not measure all its parameters then, since I sold it along with all the factory blades, since my homemade blades are much better for me

 

[Choosikick]

Thank you @hipnotic for dispelling the myths. TBH, I also thought the blade with more layers would be stiffer... E.g. there is the Vodak 4APC King Stiff&Spin, which really feels signif. stiffer than my Vodak Horejsi ALC. Also, a friend of mine (from another club) uses a blade with like 9 or 11 thin layers, and when I tried it, it felt very stiff, it also felt hard and fast, too fast (especially when engaged) for me. I knew the number of layers won't determine softness/hardness, because the Vodak 4APC King still feels soft, but I definitely thought the: more layers => more stiff implication holds. Also I thought that a blade with 1 thick and 2 thin layers will be less stiff than a second blade with the same thickness, made from 3 identically thick layers (all other things being equal). That, I assume now, is wrong too. Cheers.

I will not dissuade you, since for you the opinion on the forum turned out to be more important than your own practical experience.

 

[hipnotic]

Sergio, layers of glue affect the rigidity of the blade. If you assemble three longitudinal layers, for example, with epoxy glue, this will significantly increase rigidity.
Do this experiment - take a sheet of cardboard and apply a layer of glue on top and bottom, will the cardboard become stiffer than cardboard without glue? It will become significant.

I'm going to pull a BB here and bring out some formulas. This is how you determine the stiffness of a cantilever beam, which is an analogy to our situation:

Can you tell me how you determine E and how it is important?

As I said, it will depend on the glue. But if the glue in a core is affecting the stiffness of your blade, then you are using too much glue.

You're right, it also affects the stiffness of the blade. I have two blades with the same wood, glue, structure, thickness, size and weight, but glued together with different pressing forces. So, a blade with less pressing force on the same rubbers feels softer.

Here you start talking about stiffness but end up with softness. They are different concepts.

To confirm my words, there is also this blade - Donic Epox Topspeed OFF +. It is made only from longitudinal layers of ayus or kiri glued together with epoxy glue. This blade is fast, light and tough. It is hardly possible to play with a single-layer ayus of the same thickness at all.View attachment 27834

Sorry but this is the worst example you could have come up with... What you claim are multiple layers is just a protection layer all around the blade. The true composition is a fineline top layer / carbon / Balsa core. So exactly the opposite of what you are saying.

Thank you @hipnotic for dispelling the myths. TBH, I also thought the blade with more layers would be stiffer... E.g. there is the Vodak 4APC King Stiff&Spin, which really feels signif. stiffer than my Vodak Horejsi ALC. Also, a friend of mine (from another club) uses a blade with like 9 or 11 thin layers, and when I tried it, it felt very stiff, it also felt hard and fast, too fast (especially when engaged) for me. I knew the number of layers won't determine softness/hardness, because the Vodak 4APC King still feels soft, but I definitely thought the: more layers => more stiff implication holds. Also I thought that a blade with 1 thick and 2 thin layers will be less stiff than a second blade with the same thickness, made from 3 identically thick layers (all other things being equal). That, I assume now, is wrong too. Cheers.

This is different. More composite layers will make the blade stiffer, that is their role.

OK, 9 or 11 layers, but what is the total thickness? How are the layers oriented? Do they have some sort of composite between?

If the material is the same, then the only variables that will affect the stiffness are the bonding material and the distance between the interface of the bonded layers. The initial proposition was a 3mm core with layers of the same thickness, so 1mm layers. With this distance you cannot create a significant increase in stiffness without altering the original problem, only if you use a reinforced bonding layer. This of course changes if we increase the distance between the bonded layers, let's say for example if we had a 7mm blade with 1+5+1mm, this would be stiffer than 2+3+2mm.

 

[Choosikick]

Ok, what do you say about the cardboard?

And further

This of course changes if we increase the distance between the bonded layers, let's say for example if we had a 7mm blade with 1+5+1mm, this would be stiffer than 2+3+2mm.

But what about this?

A single layer is stiffer than any of the other combinations

What???

Where did you find the information on the blade Donic Epox Topspeed, show everyone so as not to be unfounded.

You can also tell us in more detail about the formulas that you reset, how you understand them, it will be interesting to know. Please don’t hide behind the BB, tell us what you know and how you understand it, because you were the one who posted the formulas, which means you understand this.

 

[hipnotic]

Ok, what do you say about the cardboard?

And further

But what about this?

What???

Where did you find the information on the blade Donic Epox Topspeed, show everyone so as not to be unfounded.

You can also tell us in more detail about the formulas that you reset, how you understand them, it will be interesting to know.

How thick is the layer of epoxy? If you take a 3mm piece of cardboard and apply a 1mm coat on each side of course the stiffness will increase, but if you apply 0.05mm which is even more than a regular glued layer on a blade, it will barely have an impact.

Let's stay consistent and compare oranges with oranges please. We can't talk about a blade as an example, and then another blade with a completely different structure and say the difference in behavior is due to just one thing.

Name on blade on the market that has a 3 ply core with the layers oriented in the same position. You can't because there isn't, it's purely inneficient. "let's pick up this piece of wood, saw it in pieces and then glue it exactly how it is". You want a practical example? One ply Hinoki blades are among the stiffest blades on market. 3 ply Hinoki blades also exist, and they all have an horizontal core, they are also less stiff than the 1 ply variant.

Sorry, my bad, it's not a Balsa core it's Kiri

 

[Choosikick]

The initial proposition was a 3mm core with layers of the same thickness, so 1mm layers. With this distance you cannot create a significant increase in stiffness without altering the original problem, only if you use a reinforced bonding layer.

So it is possible to achieve an increase in rigidity?

Or is still true?

A single layer is stiffer than any of the other combinations.

Isn't the glue itself a

reinforced bonding layer

?

 

[Choosikick]

How thick is the layer of epoxy? If you take a 3mm piece of cardboard and apply a 1mm coat on each side of course the stiffness will increase, but if you apply 0.05mm which is even more than a regular glued layer on a blade, it will barely have an impact.

Let's stay consistent and compare oranges with oranges please. We can't talk about a blade as an example, and then another blade with a completely different structure and say the difference in behavior is due to just one thing.

Name on blade on the market that has a 3 ply core with the layers oriented in the same position. You can't because there isn't, it's purely inneficient. "let's pick up this piece of wood, saw it in pieces and then glue it exactly how it is". You want a practical example? One ply Hinoki blades are among the stiffest blades on market. 3 ply Hinoki blades also exist, and they all have an horizontal core, they are also less stiff than the 1 ply variant.

Sorry, my bad, it's not a Balsa core it's Kiri
View attachment 27836

You are confusing something, this is not Donic Epox Topspeed.

DONIC Epox TopSpeed

купити DONIC Epox TopSpeed з доставкою по всьому світу

tt-maximum.com

There are some nice photos on this site where you can see the layers. Your blade looks completely different

I held this blade in my hands more than once, and I also carefully examined it - there was no protective tape at the end. By the way, there is also no protective tape on your blade and the handle with the emblem is not visible.

 

[Choosikick]

Here you start talking about stiffness but end up with softness. They are different concepts.

Here you are right, the blade actually feels softer, not more flexible.

 

[hipnotic]

So it is possible to achieve an increase in rigidity?

Or is still true?

Isn't the glue itself a

?

You need to re-read everything I said because I would just be saying the same thing again. Glue is not a reinforcement layer, it's a bonding layer without expressive thickness. Reinforcement fibers.

You don't seem to have a grasp on what stiffness means, I would have to explain the meaning of young modulus and moment of inertia and I just don't feel like it. You build blades, don't take my word for it, go ahead and try it.

You are confusing something, this is not Donic Epox Topspeed.
I held this blade in my hands more than once, and I also carefully examined it - there was no protective tape at the end. By the way, for some reason there is also no protective tape on your blade and the handle with the emblem is not visible.

It's Epox whatever, it's from the same line and I assumed they all followed the same structure, just did a quick Google search and apparently I was wrong and your were right about the composition. Still, it's a 7.1mm blade and they are not all oriented vertically. Top layer is fineline and the other made from another wood. Do you know any other 7.1mm one ply blade made from the same material so you can compare it? Is this blade stiffer or harder? I'm replying to all your questions but you are not replying to any of mine.

 

[Choosikick]

One ply Hinoki blades are among the stiffest blades on market.

At the same time, having such an impressive thickness, they are playable. With the same thickness, a composite blade will be much stiffer and will simply be impossible to play with.

 

[Choosikick]

You build blades, don't take my word for it, go ahead and try it.

This is closer to the point. .
I think I answered all your questions.
It’s already very late, and I didn’t notice how time flew by during the lively discussion. Tomorrow, that is, today I will be like a boiled shrimp.
I still have a question about cardboard for later. But that comes later. Good night, Sergio.

 

[hipnotic]

This is closer to the point. .
I think I answered all your questions.
It’s already very late, and I didn’t notice how time flew by during the lively discussion. Tomorrow, that is, today I will be like a boiled shrimp.
I still have a question about cardboard for later. But that comes later. Good night, Sergio.

Yeah, it was getting late so I went to sleep, but I won't debate this much more.

You didn't answer, at first at least. If you go back and edit your answer I won't know. If you don't understand the formulas then there's no point in discussing it, I'm not going to give a physics course over here. Forget I even mentioned it.

Just name one blade on the market that has 3 layers of the same material arranged vertically.

In fact, take any practical example from any field, it's just inefficient. The materials are always cross-arranged, you lose longitudinal stiffness but gain traverse stiffness and homogeneity, basically what we like to call sweetspot. The only scenario where that is viable is by using stiffer outer layers and a filler (different) core, then you can save material and weight and achieve even more rigidity.

At the same time, having such an impressive thickness, they are playable. With the same thickness, a composite blade will be much stiffer and will simply be impossible to play with.

You keep confusing concepts, now you are throwing fibers into to the mix. We are talking purely about wood, specifically layers of the same species. Go do the experiment, build a 5 ply blade and a 7 ply, don't change anything, same thickness, same glue. For the 7 ply just use 3 layers for the core with the same total thickness as the core on the 5 ply and arrange them any way you want, come back with your results. I don't need to do it because I've already did, and I have the empirical confirmation for what the formulas say.

 

[Choosikick]

The materials are always cross-arranged, you lose longitudinal stiffness but gain traverse stiffness and homogeneity, basically what we like to call sweetspot.

Yes, that's right.

And when gluing three layers located longitudinally, the rigidity will definitely increase, both longitudinal and transverse due to the adhesive layers and impregnation of the wood with glue. The result will greatly depend on the glue and gluing technology.

Also, the final characteristics of the product will be influenced by the pressing force. So to say that
"A single layer is stiffer than any of the other combinations", how did you say it, this is absolutely not a true statement.

 

[Choosikick]

but I won't debate this much more.

At the same time, you continue to do this. Moreover, you are trying to accuse me of not understanding formulas, despite the fact that I didn’t say a word about it, but wanted to hear from you first about it, since you brought it up as an argument and at the same time in the essence of this argument You didn't write anything.
Also, the issue with cardboard, about which I have already written to you at least three times, has not been resolved.
And the third is the Donic Epox Topspeed blade, which for some reason is not made of three layers with a one and “stiffer single layer” core, in your words.

 

[Choosikick]

Go do the experiment, build a 5 ply blade and a 7 ply, don't change anything, same thickness, same glue. For the 7 ply just use 3 layers for the core with the same total thickness as the core on the 5 ply and arrange them any way you want, come back with your results. I don't need to do it because I've already did, and I have the empirical confirmation for what the formulas say.

If you have already done this, please share your results. What glue did you use to assemble this, did you try using other glues and pressing forces, what were the results?

 

[Choosikick]

One ply Hinoki blades are among the stiffest blades on market.

Let me clarify my previous post on this topic, since this is not clear to you.
Single ply hinoki blades, which are among stiffest blades on market, are not the stiffest blades due to their single ply construction as you claim. Stiffness is primarily based on their large thickness while maintaining reasonable weight.
These blades are on sale and people play with them because having this stiffness, they are quite soft and playable. BB forgive me, they have control.
Creating more stiffest blades with a different construction not single-layer has no problem, but it does not make sense, since this threatens a loss of control and I doubt many people will like it and buy it

 

[igorponger]

Carbonized timber is an advanced material now widely adopted for blade layers, both inner and outer. Dont confuse with some natural woods of dark coloration.

Factory carbonization on veneers in steem chamber at 350 * C