Not again about boosting please

[brokenball]

Not fair !!!
All I posted were facts.
Namely 3 pieces of rubber off -cuts with 3 different treatments. Nothing more and nothing less.

I have found that TT forums aren't fair. So what is new. Just doing these test gives the noobs they idea that there may be something to it.

Furthermore, when joining this forum no qualifications were demanded of me or anybody else.

That is a problem.

No IQ test was needed

That is a bigger problem

and no trick questions needed to be solved.

I never liked trick questions either.

This means even complete half senile old gits like myself can post here. 😂😂😂

What is sad is that you are one of the more sane ones.

Life is hard 🤣

Yes, and it get rapidly harder as we age. I am right behind you. BUT!!!......

We can't mislead the noobs or give them any bad ideas.

BTW, I had to look up git. Would you guys stop making up new names for things we already have names for? It is like you are trying to separate US-English from AU-English from UK-English even more until they will be completely different languages. I have used geezer and curmudgeon before.
git is a way of saving versions of software. I have .git directories of revisions on my computers.

 

[tabletennisdaily1]

can you explain how you would one test the normal and horizontal coefficients of restitution of a rubber?

 

[lodro]

I have found that TT forums aren't fair. So what is new. Just doing these test gives the noobs they idea that there may be something to it.


That is a problem.


That is a bigger problem


I never liked trick questions either.


What is sad is that you are one of the more sane ones.


Yes, and it get rapidly harder as we age. I am right behind you. BUT!!!......

We can't mislead the noobs or give them any bad ideas.

BTW, I had to look up git. Would you guys stop making up new names for things we already have names for? It is like you are trying to separate US-English from AU-English from UK-English even more until they will be completely different languages. I have used geezer and curmudgeon before.
git is a way of saving versions of software. I have .git directories of revisions on my computers.

Old git is older than the pc software version.
I googled it for you :

Meaning of git in English

a person, especially a man, who is stupid or unpleasant: You stupid/lying git! He's a miserable old git. Synonyms. rotter mainly UK old-fashioned. much

 

[TensorBackhand]

Now you will have to do exactly what I did. You have to repeat the experiment on the 2 patches, the one on the left and the middle one.
The patch on the left has the glue applied before being treated with the oil and YES, the glue is inhibiting the action.
The reason however why i suggest you do your own experiment is because you are using speedglue which may show completely different
results

Well I am certain that the booster is traveling down to the sponge. Because the rubber curves up after boosting and expands.

But I wonder if its expanding less than it theoretically should without the layer of rubber cement.

 

[lodro]

Well I am certain that the booster is traveling down to the sponge. Because the rubber curves up after boosting and expands.

But I wonder if its expanding less than it theoretically should without the layer of rubber cement.

Well, like I said, look at the picture. On the patch on the left it is 3 layers on top of glue and in the middle it is the same 3 layers without glue.

Don't wonder, experiment, it's fun 🤣

 

[brokenball]

can you explain how you would one test the normal and horizontal coefficients of restitution of a rubber?

I could. I am internationally recognized for being able to do industrial testing. So why would I bother? I am retired now. This should have been addressed 10 years ago.

Maybe if I get an apology from TableTennisDaily.
USDC, knows I know how to do this.

 

[lodro]

can you explain how you would one test the normal and horizontal coefficients of restitution of a rubber?

maybe this helps ????????????????????

https://iopscience.iop.org/article/10.1088/1757-899X/36/1/012038/pdf

 

[brokenball]

This forum is full of the blind leading the blind.
Only those that see get banned.

The drop test is a good start. The problem is that the coefficient of restitution is not linear.. At higher speeds the COR starts to drop off. This was also shown in the old Tieffenbacher document. Look it up!.

 

[tabletennisdaily1]

I could. I am internationally recognized for being able to do industrial testing. So why would I bother? I am retired now. This should have been addressed 10 years ago.

Maybe if I get an apology from TableTennisDaily.
USDC, knows I know how to do this.

What? You would bother so I can understand what you are talking about. Because from my perspective, COR tells little valuable information.

What should have been addressed 10 years ago?

 

[tabletennisdaily1]

This forum is full of the blind leading the blind.
Only those that see get banned.

The drop test is a good start. The problem is that the coefficient of restitution is not linear.. At higher speeds the COR starts to drop off. This was also shown in the old Tieffenbacher document. Look it up!.

Okay, drop test is standard way to measure COR. Please explain, what is this "normal" AND "horizontal" COR you speak of? That's what's confusing me here.

Also as you previously said, COR are the only things that matter, which I don't understand because obviously spin performance and feel both matter as well. COR doesn't account for that

 

[lodro]

Okay, drop test is standard way to measure COR. Please explain, what is this "normal" AND "horizontal" COR you speak of? That's what's confusing me here.

Also as you previously said, COR are the only things that matter, which I don't understand because obviously spin performance and feel both matter as well. COR doesn't account for that

As this has nothing really to do with this thread, I suggest you two get a room 🤣

 

[Tony's Table Tennis]

well, let me add something to ponder about.

H3 commercial (orange sponge), 4 weeks old, with South African bought J&J baby oil - love it (I was surpised)
This was maybe over a decade ago, I can't remember how many layers I put on, maybe 5 or so.

few years ago, I had baby oil at home, so took an old H3 blue sponge national. Baby oil was bought in Taiwan.
Nothing happened. just made the sponge surface so sticky and it left stickiness on the blade (huge regret)

over a decade apart, 2 different countries baby oil, 2 different sponges.
One with great dome and that other flat flat flat

I know baby oil is useless, so I don't recommend waste time or energy on it.
But how many of you have tested baby oil from different countries?

 

[Tinykin]

Old git is older than the pc software version.
I googled it for you :

Meaning of git in English

a person, especially a man, who is stupid or unpleasant: You stupid/lying git! He's a miserable old git. Synonyms. rotter mainly UK old-fashioned. much

I have deliberately not looked up the dictionary meanings, but from usage in my circles, these days git is more equivalent to a small level above 'grumpy old man'. Whiler 'rotter' as in rotten, is completely different. Rotter is more equivalent to 'charlatan' or dead beat dad etc

 

[latej]

Linus said he named the git after himself .

He is a great man.

Btw. I like the 1st one, nice and uniform, I am surprised it didn't dome. How many glue layers did you put? I do only 1, it domes later, but it does dome.

 

[lodro]

Linus said he named the git after himself .

He is a great man.

Btw. I like the 1st one, nice and uniform, I am surprised it didn't dome. How many glue layers did you put? I do only 1, it domes later, but it does dome.

Actually the patches in their "virgin form" all domed very slightly the wrong way, so even patch one did dome a little.
Of course I am using the word DOME here with slight reservations. Maybe i should just call it REACTIONS 😁

My standard gluing method is 2 layers on the rubber and 1 on the blade. The glue is Revo3, the thick version but I thin it down to my liking.

BTW patch 1 an 2 have been done about a week ago and patch 3 was done on the 25th of dec 22
None of the patches show any change after 1 day of their treatment.

 

[phillypong]

In the end there seems to be very little measurable rubber characteristics data available to consumers. Its because of marketing i guess. How can we as end consumers know the real difference between rubbers/boosting etc ... Just by trying the rubbers? $$$$$ ... in the pocket of the rubber dealers ;-)

For most of us any rubber can do the job well enough, we should work more on our technique/tactics/physical abilities.

I only boost with lamp oil (kerosene), and only to restore most of the grip that can be lost after a few months of play. A few drops on the sponge before glueing and after that every 3 months on the rubber -> i can play my DHS Hurricane rubbers for 3 years each ;-) -> less money in the pockets of the rubber dealers/pushers ...

Happy ping-pong-ing guys!

 

[lodro]

In the end there seems to be very little measurable rubber characteristics data available to consumers. Its because of marketing i guess. How can we as end consumers know the real difference between rubbers/boosting etc ... Just by trying the rubbers? $$$$$ ... in the pocket of the rubber dealers ;-)

For most of us any rubber can do the job well enough, we should work more on our technique/tactics/physical abilities.

I only boost with lamp oil (kerosene), and only to restore most of the grip that can be lost after a few months of play. A few drops on the sponge before glueing and after that every 3 months on the rubber -> i can play my DHS Hurricane rubbers for 3 years each ;-) -> less money in the pockets of the rubber dealers/pushers ...

Happy ping-pong-ing guys!

I wholeheartedly agree.
btw, I think my patches come from Kokutaku rubber but you probably use a more expensive version

 

[igorponger]

No two tensors are alike. You don't know which rubber has a better trampoline effect unless you test the rubber with a laboratory testing machine known as Schob pendulum. Likewise you could surely know if the boosting procedure make a rubber sheet more bouncy or not. To my awareness, most of large-pore sponges are prone to become less bouncy after oily treatments.
Pre-warned is pre-armed.

Be happy

 

[lodro]

No two tensors are alike. You don't know which rubber has a better trampoline effect unless you test the rubber with a laboratory testing machine known as Schob pendulum. Likewise you could surely know if the boosting procedure make a rubber sheet more bouncy or not. To my awareness, most of large-pore sponges are tending to become less bouncy after oily treatments.
Pre-warned is pre-armed.

Be happy

Pleas note 2 things : 1 I am happy and 2 this was never going to be an exercise to prove anything or make any kind of statements.
I am however quite happy when more knowledgeable people get involved and sort things out.
The bottom line here is to show that indeed SOMETHING is happening when one applies chemicals and/ potions to the sponge.
What exactly has changed and if the changes have been positive or negative is not so important to me.
It is just A PLAY with some left over corners of a rubber.

If qualitative changes are important there are 2 kinds of ways to measure these.
The first one needs some machinery like for example the one you are showing and the second one is to simply compare the performance of the
home-treated rubber against the factory version on identical blades. Naturally, for some players a result might be positive while for other player it
might be highly undesirable.
C"est' la vie 😁

 

[brokenball]

Okay, drop test is standard way to measure COR. Please explain, what is this "normal" AND "horizontal" COR you speak of? That's what's confusing me here.

Also as you previously said, COR are the only things that matter, which I don't understand because obviously spin performance and feel both matter as well. COR doesn't account for that

The drop test works but it only tests and one impact velocity. Tieffenbacher showed that the normal COR changes depending on impact speed.

You seem not everyone knows what I think is obvious.
Normal is like perpendicular only perpendicular only applies to a line. Normal is similar but it applies to a plane. A flag pole is normal to the ground.
Tangential would be any motion or force along that plane that is normal to the flag pole. Now since the earth is round, a plane that is is normal to the flag pole would leave the ground as the distance between the point on the plane and the flag pole increased.

So when the ball hits the paddle, the two exert a force on each other. The force the paddle exerts on the ball can be broken down into a normal force and a tangential force. So there is a tangential and normal COR. The normal COR affects speed and the tangential COR affect spin. The COR number are between 0 and 1 but for most modern rubbers they are probably between 0.6 and 0,7. A normal COR of 0.7 means that if the ball hits the paddle at a speed relative to the paddle of10 m/s it will have a normal rebound speed of 7 m/s relative to the paddle but if you are moving the paddle towards the ball at 5 m/s the ball will be moving at 12 m/s relative to the ground/ table.

If the paddle has a tangential COR of 0.5 and the paddle is moving horizontally at 10 m/s is horizontal. The ball will travel forwards at 5 m/s or or less. Much depends on the force of impact. The tangent COR changes depending on the impact speed. Obviously, to me anyway, that if the ball only drops from 1 cm that the ball will not impact with enough force to to grip and propel the ball forwards with back spin.

I have been posting the Tiffenbacher document for years and now realizing the few understood any of it.
https://deltamotion.com/peter/TT/199408014 - Tiefenbacher - Impact.pdf
Tieffenbacher is German so he used the term Epar and Tpar for Normal COR and Tangentia GOR.
Pay attention to the second small paragraph.