Is it permitted to inflate balloons and airbeds on Shabbos?

The halachik issue pertaining to the inflating of a waterbed on Shabbos is one of Makeh B’patish – completing an article.

The Shulchan Aruch [1] teaches us that one may reinsert down (feathers and fluff) into a pillow and eiderdown but they may not be inserted for the first time. Even though the insertion does not entail physical force or any unique expertise, nevertheless it is a melacha called Makeh B’patish.

This is because the combination of the pillow and the stuffing form a k’li.

We can therefore deduce that combining two items to form a k’li will involve the issur of Makeh B’patish. Accordingly, it is prohibited to inflate a water or air bed, even when using a mechanical pump, because introducing the air or water into the bed “completes” the bed and transforms it into a usable k’li. [For the moment we are referring to the initial inflating of the water bed (the first time), as for consecutive inflating we will see further on be”H].

The same could be said when inflating helium balloons.

Why do you not say the same about regular balloons that are filled with CO₂ (air)?

Let us first examine the issue of inflating rubber ducks and then we will see the status of regular balloons.

The difference between rubber ducks, swimming pool rings and waterbeds is that the former are inflated for a limited period of time and subsequent to use are deflated, whereas a waterbed is usually inflated permanently. It is not so much the time factor that makes the difference rather it is the purpose and intent. Here is the explanation.
One does not say that a deflated swimming ring is broken, just as one does not say that a fan or light that is switched off is broken. On the other hand one does say that a waterbed without air is not fulfilling its purpose. Here is another approach.

A wind-up toy is not broken when it is not wound up and moving about because such a toy is made to wind up, be played with and put away, whereas a wristwatch that has stopped (as a result of unwinding) is considered “broken” [2] and winding it up is considered “repairing”, since a watch is supposed to tick continuously and not stop.

Accordingly, inflating a rubber duck would not be called making it, rather using it and inflating a helium balloon would be called making a balloon.

 …and a regular balloon?

A regular balloon is somewhere in the middle, because children sometimes enjoy inflating and deflating balloons, thereby using it as they do a rubber duck, but more often it is inflated and tied, which would categorize it with a water bed, and hence its inflation would be ossur.

For yet another reason one must not inflate balloons on Shabbos. After inflating a balloon one usually ties a permanent knot, which is forbidden on Shabbos. Even if one were to say that one will inflate it without tying, it is ossur, because we find that one may not thread a string through an article of clothing when one regularly ties a knot of threading. [3] Therefore one must not inflate balloons on Shabbos. [4]

If that is the case, then one should be permitted to re-inflate a waterbed on Shabbos, just as one may reinsert the down into the pillow and it is only the initial inflating that is forbidden?

We find a beautiful machlokes between the poskim on that, but we must first reintroduce another concept. One is permitted to reinsert down into the pillow it came from but it is ossur to insert other down into the pillow or insert old down into a different pillow. [5] In short, one may only reintroduce the same down into the same pillow.

Rav Weiss ztz”l says [6] that since one is not reintroducing the same air or water that was inside the bed (or soccer ball, for that matter) it is similar to inflating the bed for the first time and it is ossur to do so.

Rav Shlomo Zalman Auerbach ztz”l, on the other hand, says [7] that air is air and therefore once an air or waterbed etc. has been inflated for the first time, one may re-inflate it on Shabbos because one is reinserting air similar to the reinserting of the down into the pillow.

To Summarize

It is ossur to inflate waterbeds or soccer balls for the first time. After the first time it is a machlokes. One may not inflate a balloon on Shabbos.

It is permitted to inflate a rubber duck and a swimming ring even for the first time on Shabbos.