Balsa and anti-spin rubber.
This post is an attempt to explain how balsa works in blades when combined with anti-spin rubbers. Balsa comes in about 50 varieties, with each variety having slightly different properties; anti-spin rubbers come in varieties as well; so general statements about them are bound to be inexact, but in my opinion need not be inconclusive. Both balsa and anti-spin rubbers have basic properties which are the same for all their varieties, viz. balsa is a wood with a low density resulting in a typical catapult, and anti-spin rubbers have low friction and are attached to sponges; I’ll argue that these basic properties explain the basic problem occurring when balsa and anti-spin rubbers are combined, viz. a variability that conflicts with control in most situations (not in all) for most players (not all).
In relation to the use of anti-spin rubbers balsa’s main problem is that its catapult is increasing disproportionately with increasing impact. In practice, this means that on low impact balsa has a dampening effect, absorbing speed, and an accordingly high dwell-time; at high impact it has an accelerating effect and an accordingly diminished dwell-time. This also means balsa’s throw will be lower with increasing impact. The effect balsa has, as a result of this, on sandwiched rubbers is that on low impact the sponge seems to be a slow thick one and at high impact it seems to be a thin fast one; the top-sheet seems to have more grip at low impact and less at high impact; and the trajectory of the ball on return will be flatter with increasing impact.
Anti-spin rubbers depend to a great extent on their sponge for their grip on the ball and to a lesser extent on their top-sheet. At low impact the grip of the sponge will be high, the grip of the top-sheet will be high as well, and so the trajectory of the ball will be high too, but speed will be very low, so the trajectory will be short and will curve down quickly (especially when incoming backspin is partly reversed and the dropping effect of the topspin returned is added to gravity). As impact increases, the combined grip of the rubber’s top-sheet and sponge will decrease and the trajectory of the ball will become flatter and longer.
In practice this means that returning slow balls you will be at risk of dumping them into the net, whereas returning faster balls you are at risk of overshooting the table. This will feel as a lack of control and it will be increased during play, because the first balls in a rally tend to be the slower ones and you will tend to compensate for the short trajectory of the ball by opening your blade a bit, which will be disastrous when returning the next, faster ball, as it will go extra long because of the effect of the catapult combined with the blade’s angle. The growing feel of lack of control will influence the player’s game negatively, so the physical problems with balsa and anti-spin rubbers will be added to the resulting psychological problems, and the combined result will be even more negative.
With normal inverted rubbers the combination of balsa’s catapult and the player’s response to its effects is much less disastrous. Slow balls are looped or pushed, as a rule, and with those strokes the extra grip and relative high throw will increase effectiveness and induce a feeling of safety. Fast balls are hit, blocked or chopped; doing that with low throw and high speed tends to be very effective, even if there is a risk of the ball going long or touching (or ending up in) the net. Since the strokes tend to work out effectively it is also easier psychologically to adjust, as you will not feel that you have lost control. All in all, then, in practice balsa will tend to work out pretty well with inverted, especially for players who have an active game.
The effect on rubbers without sponge is different again, because now there is no sponge, so the effect of balsa to make sponge feel thicker and slower on low impact and the reverse on high impact, simply is not there. Handling low speed balls the rubber will feel slow, but as there will also be slightly more grip, adjusting to it by using a more active stroke will be effective and so the player will feel no loss of control. Aggressively pushing low speed balls will feel easier, in fact, because of the increased grip. Blocking high speed balls the rubber will feel faster, but throw will be lower – as there will be backspin on the ball, and the player knows this, he also knows that the ball will not land on account of the spin, but because of gravity, so he will tend to compensate for the incoming speed by blocking soft (which will take the speed extra effectively off the ball, as the balsa’s catapult drops fast) and by placing as short as he can (which will prevent the ball from sailing long). So, as a combination of psychological factors and the way wood and rubber interact, it is unlikely the player will feel a lack of control. Balsa will work out partly positive on OX rubbers and this provides a feeling of safety which will work out positively on the players game.
The above is a very general analysis, so now let’s look at some details, concentrating on anti-spin rubbers and how they are generally used.
If an anti-spin rubber is used for attack, the tactically most important stroke is the one with high impact. For attack, typically rubbers with thick sponge are used (2.0 to 2.5 mm), as the sponge has to grip the ball (the top-sheet won’t do that, as it is low in friction). A sponge this thick will dampen impact considerably, making the effect of the balsa less pronounced; but the effect will still be present, and more so as impact is higher, so it will interfere with the anti-spin rubber’s desired property (its sponge grabbing the ball) but may enhance another one (the lack of grip of the top-sheet, resulting in spin-reversal).
Anti-spin attack rubbers are as a rule combined with inverted rubbers used for quick attack; when hitting hard, the balsa will disrupt their grip on the ball as well, but players will likely be able to compensate for it (see above).
All in all, the situation is rather complex, possibly confusing in some situations, so less than ideal.
If an anti-spin rubber is used for pushing Solja-style, the most important stroke is aggressively handling slow balls – incoming speed is low (as backspin balls tend to be slow), but the ball is attacked, so the resulting impact will almost always be medium high. The rubber’s sponge has to be thin and hard to maximize reversal and for the same reason the top-sheet will have very low grip. This means that the effect of the balsa is not diminished much by the sponge, but is pretty constant on account of the type of stroke used. As a result, control will be constant too, but only insofar as the player is able to use the same aggressive push in every situation. For when impact is low, speed will be absorbed to a great extent; this makes the push less aggressive and so it has to be avoided. When impact is high, for instance when the player blocks a fast ball or hits, the balsa will increase the speed and diminish the grip, which will lessen control. As a consequence, if the player does not have the best possible tactical and technical abilities, the situation is less than ideal. Amelie can pull it off, but who else?
If anti-spin rubber is used for passive blocking, in order to disrupt the opponent’s play by absorbing his speed and reversing his spin, all kinds of impact will occur. If the sponge of the rubber is relatively thick and hard, it is possible to dampen the impact to some degree, which will reduce impact to being moderate or low, and the combination of balsa and rubber will more or less function as desired. However, this kind of sponge will likely not provide the required degree of reversal. If the rubber is relatively thin, the balsa will interfere in a negative way, unless the player will be able to compensate in the same way a very thick sponge would – this requires very fine touch. Veteran superstar Herbert Neubauer is playing like this nowadays, but even he is less successful using his antis on balsa than he was using his OX long pips on balsa.
If anti-spin rubber is used for chopping at mid- and long-distance, impact will be medium to low. As anti-spin rubbers for this type of defence tend to have medium thick sponge, the effect of the balsa will be present to some extent. At long distance, impact is always low; balsa will dampen the speed; but speed is needed to get the ball on the table, so the player has to chop with more forward force and this will interfere with reversal and adding spin. But at mid-distance, impact is mostly moderate; the speed required to return the ball is also moderate; so the effect of the balsa will be rather constant and not interfere much, which means the combination with anti-spin rubbers is viable in this situation.
If anti-spin rubbers are used for all-round play, all types of situations occur, so the combination with balsa will be at times negative and at times positive; as this makes play as a whole hard to predict, a definite lack of control will be felt, and hence the combination is less than ideal.
Summing up, balsa and anti as a rule do not go well together, except when impact is consistently of one kind only.
It has to be added that the effects of balsa increase dramatically with the thickness of the ply or plies used in a blade. They are very small if the balsa plies are under 2.0 mm thick. Normally, if a balsa effect is wanted by a builder, the minimum thickness used is 2.5 mm. Plies over 4.5 mm thick produce a large effect.
So when playing with anti you would like to have a balsa blade (for example because you want it to be light-weight), using it for mid-distance defence, or the same combined with close to the table attack, which for regular players seem to be the two types of play which are practically compatible with balsa, you should probably look for a blade with a thin balsa core or two very thin inner balsa plies (combined thickness between 2.0 to 4.5 mm), offering a moderate balsa effect. For anything else, the balsa should be less than 2.0 mm thick, or not there at all.
Without opponent, no match.