What Are Hybrid Table Tennis Rubbers and Why Are They So Popular Nowadays?

[Archosaurus]

Cool I will check @Archosaurus thanks! And agreed, it's always a bit of a puzzle with Chinese products, naming of versions and subversions goes a bit left and right haha

Sellers seem to suggest that the packaging changes are just branding changes and the product is the same. Maybe they've changed it, but at least it's not a separate version.

So there's Training, Pro, Classic Pro and Professional.

 

[victormanriquey]

None of this is scientifically verified, but:

The different National versions are more or less dense formulations of Seamoon with a dye. The order should be something like Black > White > Yellow > Seamoon. I don't know where Red, Brown, 2017 or any other obscure versions fall.

The peak effect lasts a day or two or so, then a stable high effect for 1 to 2 weeks (Haifu claims +8.5% for 1 week for Black), then drop off to nothing after about 3 to 4 weeks.

They all soften the sponge maximally as much (Maxing out at around 9deg softening for many sponges I've boosted 4-6 times to see where it reaches asymptote) although the stronger national boosters soften it faster, and denser sponges soften more per layer.

Black softens the sponge the easiest and Seamoon the hardest. However you need less of Black to get a similar elasticity effect as with Seamoon, so maybe there's a breakpoint where you get more elasticity than you get softening. I have no clue where the idea that Black softens the sponge less comes from; I find on average 1deg more per layer (2ml or so) than with Seamoon.

I've found on less dense sponges with Seamoon it can be as little as 1deg per layer, while on dense sponges with Black it can be as much as 3deg per layer.

In practical use I haven't noticed a real difference other than National boosters are stronger so you can get less added racket mass for the same softening and elasticity. Black and White are a lot stickier and much harder to evenly apply than Seamoon, and harder to drain back into the bottle. I haven't tried Yellow but under spectrometry it's identical to Seamoon so it's probably just a denser variant as well.

Yeah its really hard to find something scientifical on this, it's just tests of people doing their best
But indeed I agree my new national yellow is thicker than the commercial I have, that I can tell you.
There is indeed a peak period of 1-2 weeks in the commercial, then it's back to like semi boosted, then after around 1-2 months its pretty much dead again with a slight feeling of being boosted, it does play easier then.
For the national they claim that it lasts longer, let's see, it would make sense if its more concentrated.
I haven't tested black so I trust you on that @Archosaurus , need to test more in future the different colors to say

 

[Archosaurus]

Yeah its really hard to find something scientifical on this, it's just tests of people doing their best
But indeed I agree my new national yellow is thicker than the commercial I have, that I can tell you.
There is indeed a peak period of 1-2 weeks in the commercial, then it's back to like semi boosted, then after around 1-2 months its pretty much dead again with a slight feeling of being boosted, it does play easier then.
For the national they claim that it lasts longer, let's see, it would make sense if its more concentrated.
I haven't tested black so I trust you on that @Archosaurus , need to test more in future the different colors to say

The top end speed and hardness reduction does go away quickly. In fact most of the hardness reduction probably reverts towards the unboosted level just from gluing, because the hardness goes way up as soon as I glue then measure topsheet when it's attached to the blade. I don't remember how much it is because I never wrote it down, but most of it comes back after gluing. I would expect hardness to go down further because there's more stuff in series with the rubber.

I should check some time if it also goes up a bit more after removing from the blade right after. I didn't confirm when I measured one time if it was an effect of the gluing or the removing, I only measured it after removing. Hardness on a Battle 2 Gold went from 44.0 O to 47.0 O from gluing then removing. Unboosted was 49.0 O.

So most of the effect you will lose is the top end speed. However I feel like the bottom speed lasts somewhat permanently, until you've boosted around 6-8 layers after which that starts to reduce as well.
Although so much boosting in my case has always been coupled with use over a couple months, so it might just be the trauma from impacts destroying the sponge and topsheet.
If you boost a sheet once or twice even infrequently, it will become a bit more hybrid-like somewhat permanently. Maybe not for months and months, but longer than a few weeks. Until you overdo it and then it seems to become worse overall.

The thing you need to be careful with here is that:
A: It's really difficult to measure things like elasticity without destroying the sponge, so forming a curve of measurements with reliable parameters is very difficult/costly
B: It's really difficult to make useful inferences from lab data because practical use often isn't normalized to what you'd normalize the lab data to
C: Finding what to normalize the lab data to is very difficult because a lot of parameters are inherently tied to eachother

So us tabletennis equipment sickos will probably never actually find a definitive answer to the physics aspect of it which is why I stick to very practical-normalized things like "layers" and not masses or volumes.

A simulation would help a lot, but rubber is one of the more complicated materials to model and small errors can really skew the outputs of the simulation a lot due to the relatively high volatility of the structures, so you might even make the wrong conclusions from a sim unless it's very expertly made.