At our club, different players are using the Xushaofa *** (seamless) plastic balls. They are very good except when we are hitting on the edge of the bat, balls break.
To prevent that, we made tests using ''SPONGE RUBBER TAPE'' (self adhesive) and it's working great. No more broken balls when you hit on the edge, the black sponge is protecting. (this tape is mostly used to seal windows)
There are different sizes available but thickness of 0.125 inches (1/8'' or 3mm) and width of 0.375 inches (3/8'' or 9mm) is fine. Easy to install, just remove the white paper backing and press it on the edge of your bat. Moreover, you can remove it and put it back many times as the glue is staying on the black sponge.
It will increase the weight of about 1 gram if you put it all around your bat. (you can put it only at one part of your bat)
It's protecting your blade much more than the conventional edge tape if you hit the table. (no black scratch on the table too)
It seems that there is no ITTF rule indicating that it is not legal. (if there is, just remove it for the tournament and put it back after)
It's not expensive and it's available at any home maintenance retailer. For example, $8.00 for 17 feet (5.2 meters) long (nearly 13 bats) at Home hardware.
Here is this ''SPONGE RUBBER TAPE'' at Home hardware:
http://www.homehardware.ca/en/rec/index.htm/Hardware/Builders/Weatherstrip/Foam-Tapes/1-8-x-3-8-x-17-Black-Rubber-Sponge-Weatherstripping-Tape/_/N-2pqfZ67l/Ne-67n/Ntk-All_EN/R-I2395429?Ntt=Sponge+Rubber+Tape
