Daily Table Tennis Chit Chat

[Archosaurus]

I'm much more inclined to think your measurement is wrong than the manufacturer, because Shore A 23.5 would make Tenergy somewhere around 33 ESN, and that's obviously not the case.

Scales are not directly comparable on nonlinear elastomers. Even on Chinese rubber the methodology doesn't add up, and a 40A sponge can measure 40A but measure anywhere from 49 to 55 O typically.

Dignics sponge measures 46 and is reported as a 40, so with the less progressive Tenergy sponge, at 36 hardness, I would not be surprised if it's closer to 40. Eventually I'll get a Tenergy 05 sheet for myself and just post numbers.

FWIW my measurement doesn't differ more than 1deg from what ESN claims for their products. My Europe Vega DF for example measured 37.3 - 37.5, with a claimed hardness of 37.5. Nittaku rubbers also measure exactly. So I don't think my durometer is miscalibrated.

Bear in mind that if you press the durometer into the sponge, it will measure harder artificially. You just need to sink the needle.

 

[jonol]

Well, you can post whatever numbers you like but I can assure you that no one is going to believe you that Tenergy is 23.5 Shore A/33 ESN, a full 14.5 degrees less than Fastarc G1 - and 12.5 degrees lower than Butterfly's rating.

Your readings are clearly not consistent, if not entirely wrong.

 

[Archosaurus]

Well, you can post whatever numbers you like but I can assure you that no one is going to believe you that Tenergy is 33 ESN, a full 14.5 degrees less than Fastarc G1.

Your readings are clearly not consistent, if not entirely wrong.

Tenergy is not 33 Shore O because that's not how this works at all. The only time you can compare scales is when you're measuring a rubber brick that has no progression whatsoever. These 2mm thick elastomers with complex air cavity geometry are really far from that. Especially Spring Sponge. To get an idea you'd need to measure it with at least 3 scales which sink to different depths, then test with other models as a control.

Fastarc G-1 is 47 - 47.5 O.
Tenergy 05 Hard is 29.5 A.
Dignics 09C Commercial is 32.5 A.
Dignics 09C JNT is 34.0 A.
Dignics 80* Commercial is 46.0 O.
Dignics 05 CNT is 32.5 A.

EDIT: And if the scales have different indenter head shapes and thus different contact pressure, it's not comparable anyway. A and O differ. To get an actual accurate measurement, you'd need to change the spring without changing the head. As per ASTM D2240 the maximal spring force is 8.065N although the actual contact force differs, I think O is 12N while I don't remember A.

EDIT 2: A and O are 8.065N spring and both have 12.5N contact force at 100.

A tip area is 1.96mm^2 and O tip area is 4.45mm^2. This isn't *really* accurate but it's relatively comparable to get the idea.

12.5 N / 0.00000196 m^2 = 6.377,551 Pa or 6.38 MPa.
12.5 N / 0.00000445 m^2 = 2,808,989 Pa or 2.81 MPa.

Point I'm trying to make is that even if the maximum contact force is the same and the indenters are the same length (2.5mm), you're going to get quite different real results when measuring anything that's not fully solid.

That nifty conversion that says O is roughly 10-13 higher than A is pretty usable if what you're measuring is dense and large. I find Chinese sponges in the harder measurements don't differ so much from that. +-5% K roughly.

 

[NextLevel]

If I go to a club, I will do the two I recommend. I could definitely do the pancake one without going to a club.

So the qualiry ans video length is expect are to be higher than this but posting thoa so that people realize ir is not impossible. I do want to give away blades lol.

 

[Archosaurus]

So the qualiry ans video length is expect are to be higher than this but posting thoa so that people realize ir is not impossible. I do want to give away blades lol.

Does bouncing the ball on the bottom of the handle count? Totally not posting this because that's the only trick I do on my breaks and I have an unfair advantage.

 

[NextLevel]

Does bouncing the ball on the bottom of the handle count? Totally not posting this because that's the only trick I do on my breaks and I have an unfair advantage.

Its not on the pre approved list unless Freitas did it in the video above and if not amd you decide to submit it, good luck!

 

[Archosaurus]

Its not on the pre approved list unless Freitas did it in the video above and if not amd you decide to submit it, good luck!

I can do about 8. Maybe 10 on a good day. Does that at least get me a picture of a blade?