Sponge Hardness new Video

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I have the same durometer as you. Along with the durometer were instructions on how to use it. You're supposed to use both hands with the index fingers cradling the bottom and two thumbs on the top part.

I also found that I can get the durometer to read 60+ degrees if I just press down fast as hard as I can.

However, with the above two handed technique and constant slow pressure, the readings become very consistent. By this I mean I will measure one rubber 6 or 7 times and it'll be within one degree of each reading. Then I'll do the same with a different rubber and have the same consistency. This is true if the rubber measured is 45d sponge or 51d. Also, I measure from both sponge side and topsheet side.

You maybe want to redo your video with a different technique.

Thanks for sharing this. No instructions on measuring technique came with my durometer.
 
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I've found that measuring rubber cuttings gives you inconsistent readings compared to the whole sheet. When measuring entire rubber readings are consistent within 1 degree or so. With cuttings it can be 3-4+ difference. I wouldn't rely on cuttings.

When I said "edges" earlier I actually meant "corners". So these are approx. 4x4 cm pieces of the rubber, and the measuring head of the durometer is 2mm. I never measured sponge only, I measure on the sponge (not on the top-sheet), but the rubber is whole. I think measuring on the top-sheet is too imprecise with that durometer, because you may hit pip, or the hole in between, or some mixture. For that, a bigger head would be required.
 
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Yeah, I know it doesn't really convert. But It should still be in the ballpark, as we're not comparing hardness of different materials, we're comparing the same materials but measured with different scale. Otherwise, how could we ever compare the hardness of anything? The scale for shore A and asker C shows that 40 on shore A is somewhere in the range of 65 on asker C, that's a roughly 20% difference compared to the general consensus of it being around 55 of whatever scale ESN is. Which is why I highly doubt ESN is using asker C as their scale. Or it could be the other way around, ESN is using asker C, but DHS isn't using shore A.

Also I need to point out that using a durometer to measure a combined hardness of rubber and sponge isn't a good representation of what the hardness says on the package. For example, I bought a shore A durometer a while back and tested it on two sheets of Victas TD, I measured 10 spots on the rubber (four corners, four sides, two in the middle) and averages to around 37. On the package however it is marked as 57.5.

Anyway, I believe that people shouldn't be too focused on what the actual hardness of a rubber is. As long as it works for you why bother? And comparing hardness among different brands, or even among different models of the same brand doesn't really get you anywhere.
Not even in the ballpark. Conversion charts only work for readings taken with different hardness scale on the same specimen. They don't transfer well from specimen to specimen, let alone different manufacturers.

It is beyond doubt that DHS use Shore A for in-house rubbers and highly likely Asker C for ESN rubbers. There is a paper from 1999 by DHS on the making of sponge, authored by none other than the former senior engineer, and a female, who developed the Hurricane series etc., in which it is stated the Shore A hardness scale is used. Other than the articles in Table Tennis World, there is also the official DHS FAQ from the 2nd link from 2017 above (reproduced below).

From official DHS FAQ,

为什么金弓5&8的度数都比较高?
依照德国套胶的传统,金弓5&8采用了邵氏C硬度标准,红双喜狂飚等套胶则一直使用邵氏A硬度标注。邵氏A为针孔式测试,邵氏C则为球形测试方法,这两者不可直接换算。
一般来说,同样的海绵,邵氏C的测试硬度数值较大。海绵越硬,两种测试方法下的硬度数值差越大。
金弓的42.5度相当于邵氏A的32-33度左右,47.5度相当于邵氏A的34-35度左右,50度相当于邵氏A的36-37度左右。
"Conforming with the tradition of German rubbers, Gold Arc 5&8 use the Shore C hardness scale, whereas DHS Hurricane series uses the Shore A hardness scale. Shore A is a pin type test, while Shore C is a ball type test, therefore there is no direct comparison between the two.

In general, for the same sponge, Shore C has a higher hardness value. The harder the sponge, the greater the difference when tested by the two scales.

Gold Arc 42.5 is roughly equal to 32-33 Shore A, 47.5 is roughly equal to 34-35 Shore A, and 50 is roughly equal to 36-37 Shore A."

Compare those numbers with the ones in the conversion chart provided by 729 below (3rd link from 2017 above (reproduced below).

On the back of 729-08, "Shore C scale(Int. Standard) and Shore A scale(Ind. Standard)" are printed on that label.
Zm7VKyN.jpg

Compare again with the ones in the conversion chart provided by Yinhe when they switched from highly likely Asker C to Shore A in 2010 below.

Left - Shore Ball Type (Tianjin School)
Right - Shore Pin Type (Shanghai School)
ovupT5u.jpg


For the Victas rubbers, you're comparing readings in Shore A with one highly likely in Asker C. Table Tennis Kingdom have measured many popular rubbers, as is (topsheet + sponge), with Asker C durometer in 2015 and 2021 (see values for Triple below). There is no doubt overall hardness will measure differently from sponge hardness, but the difference would still be closer than comparing between different hardness scales.

Victas
Triple Double Extra 57.5±3
Asker C 57.9 (n=4)
Triple Extra 55±3
Asker C 52.8 (n=1)
Triple Regular 42.5±3
Asker C 49.1 (n=1)
 
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When I said "edges" earlier I actually meant "corners". So these are approx. 4x4 cm pieces of the rubber, and the measuring head of the durometer is 2mm. I never measured sponge only, I measure on the sponge (not on the top-sheet), but the rubber is whole. I think measuring on the top-sheet is too imprecise with that durometer, because you may hit pip, or the hole in between, or some mixture. For that, a bigger head would be required.

OK I see. While the measuring pin is very small indeed, I was able to get consistent readings measuring from the top sheet. I measure the top sheet in several different locations. A few towards the middle and a few towards the edges of the racket. Generally all readings are within 1 degree of each other. I write down the rough average of all the readings as a single number in my spreadsheet.

I don't know if I got a more consistent model of the durometer or if the method I'm using is more consistent, but I'm confident in it's consistency.
 
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OK I see. While the measuring pin is very small indeed, I was able to get consistent readings measuring from the top sheet. I measure the top sheet in several different locations. A few towards the middle and a few towards the edges of the racket. Generally all readings are within 1 degree of each other. I write down the rough average of all the readings as a single number in my spreadsheet.

I don't know if I got a more consistent model of the durometer or if the method I'm using is more consistent, but I'm confident in it's consistency.
will this spreadsheet ever be published?
 
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will this spreadsheet ever be published?
I've only measured about 8 or 9 sheets of rubber and none of them are very popular. At some point I've commented on all of them. I was thinking we can have a shared spreadsheet, but we'd have to use the same model durometer and technique for it to be accurate. Seems to be very picky with different results for us.
 
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@ zeio

Uniformity of testing standards should be some bounty to the customers.

-- Actually, it brings in much of confusion with customers as they encounter with so many hardness standards on the market. We recently came out with a proposal that manufacturers all should agree on solely using Shore A as a standard hardness scale. It is expected to help a lot for our players when looking for a specific rubber from different suppliers on market.

Also, we found it necessary to mark every sponge on market with an "identity print", on the backside. This is to prevent players from replacing original factory sponge. We are now reported some players using non-rubber materials as a bottom sheet on sandwich rubbers. No control breeds cheaters, sorry.

_________________________
FAIR PLAY FIRST
 
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Not even in the ballpark. Conversion charts only work for readings taken with different hardness scale on the same specimen. They don't transfer well from specimen to specimen, let alone different manufacturers.

It is beyond doubt that DHS use Shore A for in-house rubbers and highly likely Asker C for ESN rubbers. There is a paper from 1999 by DHS on the making of sponge, authored by none other than the former senior engineer, and a female, who developed the Hurricane series etc., in which it is stated the Shore A hardness scale is used. Other than the articles in Table Tennis World, there is also the official DHS FAQ from the 2nd link from 2017 above (reproduced below).



Compare those numbers with the ones in the conversion chart provided by 729 below (3rd link from 2017 above (reproduced below).



Compare again with the ones in the conversion chart provided by Yinhe when they switched from highly likely Asker C to Shore A in 2010 below.

Left - Shore Ball Type (Tianjin School)
Right - Shore Pin Type (Shanghai School)
ovupT5u.jpg


For the Victas rubbers, you're comparing readings in Shore A with one highly likely in Asker C. Table Tennis Kingdom have measured many popular rubbers, as is (topsheet + sponge), with Asker C durometer in 2015 and 2021 (see values for Triple below). There is no doubt overall hardness will measure differently from sponge hardness, but the difference would still be closer than comparing between different hardness scales.

Victas
Triple Double Extra 57.5±3
Asker C 57.9 (n=4)
Triple Extra 55±3
Asker C 52.8 (n=1)
Triple Regular 42.5±3
Asker C 49.1 (n=1)

You missed the point there. All I'm trying to say is what ESN is using as their scale is purely based on speculation. And also this:

I believe that people shouldn't be too focused on what the actual hardness of a rubber is. As long as it works for you why bother? And comparing hardness among different brands, or even among different models of the same brand doesn't really get you anywhere.
 
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BEWARE OF THE MISLEADING HARDNESS PRESENT ON 729 RUBBER PRODUCTS.

妈 锦 硬 度 数 照 表
郡 氏 C 硬度 郡 氏 A 硬度
国际 标准
行业 标准
49° 40~41°
47° 38~39°
45° 36~37°

Supposedly, this numerical hardness specification labeled on the 729-08 packet offers a misleading data. The "C" hardness don't look reliable. Hence, we only accept the Shore A numbers.
729 labeled hardness .jpg
 
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Soulspin@ rubber maker came out with an expert vision of the rubber selection by hardness.
( all given numbers are taken with Shore O durometer, using a ready-made combination sponge + topsheet )

https://soulspin.de/en/tips/table-tennis-rubber-hardness/

General guidelines in brief to remember.

Generally speaking, the more skilled you are, the harder rubbers you can play. If you like to play rubbers with a lot of "katapult", you should go for soft to medium-hard rubbers.
 
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There is some good stuff and some bad in this link.
There is also some contradictions and obviously a lot of opinion.

1 I think it is good they test the top sheet and sponge together. However, the top sheet has more affect on the hardness than the rubber. What if the top sheet was very hard and the sponge soft. Some frictionless antis are like this. Frictionless antis often have top sheets that are very stiff or brittle. They won't bend without causing a crease that won't go away. What I object to is that the durometer uses a small pin instead of a bigger object that would better represent a TT ball.

2.
The more the sponge is compressed, the longer the ball has contact with the rubber. Accordingly, you as a player have more time to influence the ball in terms of direction, speed and spin
True

. At the same time, this compression makes the rubber less precise
Why? Apparently having more time to influence the speed and spin is bad. IE Dwell time is bad.

and reduces the speed.
Maybe. How hard the sponge is isn't as important as the COR ( coefficient of restitution ).
In both cases the ball, topsheet, spong and blade will absorb ALL the kinetic energy of the impact. Some light softer sponges have more air pockets that are very springy and return a lot of energy to the ball. The article mentions this below. It is a contradiction.

3 hard rubbers.
Hard table tennis rubbers usually have little catapult and are therefore easier to control in short-short play . The balls are not catapulted out of the surface as much and are easier to control. Short strokes are also easier to play with hard rubbers. Hard table tennis rubbers are generally easy to calculate in all game situations.
True, but it is the catapult effect that give the rubber more speed. This contradict what the article said before.
Also, how hard it do hard?
If hard rubbers are good for short-short play, why isn't hard rubber good for beginners that most play close to the table? Another contradiction.

However, to fully exploit the potential of rubbers with hard sponge, you need a lot of training and conditioning. You have to work with strong arm pull and a lot of footwork and always stand right to the ball.
Why if the claim is harder rubbers are faster then why does it take extra paddle speed to get the ball back over the net?
All rubbers require footwork. Even the push blockers with LP 0X or frictionless anti.

The harder the rubber, the more power it has.
BS. Rubbers don't have power. The have a normal and tangential coefficient of restitution.

Higher rotation speeds can be played.
Again, BS. The trampoline effect works both in the normal and tangential directions. The stretching of the top sheet and snapping back adds extra spin.

However, as any table tennis rubber becomes harder, it also becomes harder to play. It is not for nothing that table tennis professionals mostly play rubbers with hard sponges.
This is an opinion. I think it depends on how you play.

4 medium hard
They have a longer ball contact time than harder rubbers because the ball can compress the sponge more at impact. The longer ball contact makes them a little easier to control and more forgiving of mistakes.
This contradicts what was said earlier in the article where it says that hard rubbers are easier to control. Oh well, yet another contradiction.

Rubbers with medium hard sponge are often equipped with a strong catapult. This has the advantage that you can get a lot of speed into the ball even with less arm pull and footwork.
This contradicts and earlier statement that says that harder rubbers are faster. Another contradiction.

BTW, foot work is still required for medium hard rubbers. You still need to get the paddle in front of the ball.

5 soft rubbers
That’s why you have the highest control with them, at least with soft topspins and soft undercut balls.
Again, another contradiction of previous statements.

5 conclusion
Table tennis rubbers also need to be tried out and tested to see which degree of hardness best suits one’s own game.
YES! Hardness is a preference and has advantages and disadvantages. Choose what is best for you and how you play?

Generally speaking, the more skilled you are, the harder rubbers you can play.
Non sense. It isn't about skill level but more about how you play.

If you like to play rubbers with a lot of catapult, you should go for soft to medium hard rubbers.
Another contradiction. Medium hard rubbers may have a lot of the trampoline effect but the article admits that hard rubbers don't. Another contradiction.

@Igor! Why are you posting this garbage! I thought you were an engineer that would see all the contradictions!
 
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You missed the point there. All I'm trying to say is what ESN is using as their scale is purely based on speculation. And also this:
What I'm saying is that one cannot deduce (or rule out) the hardness scale simply by looking at a conversion chart. That's how some folks (mostly in Europe) come to the conclusion that ESN use Shore O, by "converting" Shore A value and matching it to whatever hardness scale that "sounds close enough".

ESN using highly likely Asker C is not "purely based on speculation". There is mounting evidence that points to it being the case.

Your last quote is essentially the same as saying "We're all gonna die someday. What does it matter?".
 
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What I'm saying is that one cannot deduce (or rule out) the hardness scale simply by looking at a conversion chart. That's how some folks (mostly in Europe) come to the conclusion that ESN use Shore O, by "converting" Shore A value and matching it to whatever hardness scale that "sounds close enough".

ESN using highly likely Asker C is not "purely based on speculation". There is mounting evidence that points to it being the case.

Your last quote is essentially the same as saying "We're all gonna die someday. What does it matter?".

As long as no one from ESN comes out to say they're using Asker C, it's just speculation. And it's not the same as saying "We're all gonna die someday. What does it matter?". But if that's what you want to believe then it's what you believe, I just believe that sponge hardness is just a number, as long as the rubber helps one play better, why does it matter if it's 55 or 39 or 45?
 
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The forum is too hung up on rubber hardness. There is such a thing as too soft or too hard. Hardness is a preference but hardness is mostly determined by the top sheet. If the top sheet is hard like modern frictionless antis then the sponge will not matter much. It is also not realistic to use a small point to provide information about a much rounder TT ball. Also, there aren't any useful units for hardness. How is hardness used in an equation? What people should pay more attention is the coefficient of restitution. The COR can be used in an equation. The COR is representative of how "springy" or the "trampoline" effect is. I have been saying this for years but no one seems to listen. I think it is because the manufacturers don't provide COR number for their rubbers. That would be too informative. Instead the TT manufacturers mislead and distract the ignorant with "hardness"

There is too hard and too soft and in between is a preference.
 
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Hey Duke, important is not the number, but the relation to other rubbers, which we get via those numbers.
The important thing is not the relationship to other rubbers, it's how they make you feel when you play with them. I'm pretty sure mostly everyone knows that the hardness is for the sponge only, not the entire sheet (sponge + top sheet = entire sheet).
 
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As long as no one from ESN comes out to say they're using Asker C, it's just speculation. And it's not the same as saying "We're all gonna die someday. What does it matter?". But if that's what you want to believe then it's what you believe, I just believe that sponge hardness is just a number, as long as the rubber helps one play better, why does it matter if it's 55 or 39 or 45?
Me: I could narrow it down to Asker C or Shore E with a single image, and one from ESN.
You: Nothing but speculation and conjecture.

Who do you think people will find is closer to the truth and more informative? Refer to first image below to see why knowing the specific scale in addition to the number is useful. Refer to second image below to see why knowing something is better than knowing nothing.

https://www.researchgate.net/publication/348184425_Science_Speculation
Despite wide recognition that speculation is critical for successful science, philosophers have attended little to it. When they have, speculation has been characterized in narrowly epistemic terms: a hypothesis is speculative due to its (lack of) evidential support. These ‘evidence-first’ accounts provide little guidance for what makes speculation productive or egregious, nor how to foster the former while avoiding the latter.

http://www.sundns.org/discuz/forum.php?mod=redirect&goto=findpost&ptid=257228&pid=6111427
PKvil6p.png


https://web.archive.org/web/2012081...ristics-of-blade-materials/Page-3.html#120733
G9W7cqK.png
 
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Me: I could narrow it down to Asker C or Shore E with a single image, and one from ESN.
You: Nothing but speculation and conjecture.

Who do you think people will find is closer to the truth and more informative? Refer to first image below to see why knowing the specific scale in addition to the number is useful. Refer to second image below to see why knowing something is better than knowing nothing.

https://www.researchgate.net/publication/348184425_Science_Speculation


http://www.sundns.org/discuz/forum.php?mod=redirect&goto=findpost&ptid=257228&pid=6111427
PKvil6p.png


https://web.archive.org/web/2012081...ristics-of-blade-materials/Page-3.html#120733
G9W7cqK.png
So ESN is not Shore O? I thought everybody said it is Shore O
 
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