We were puzzled in our Shiur as to whether a wick (pesilah) is considered a keli or not?
On the one hand, Rashi brings that Ein Godlin Pesilah BeYom Tov. The Mishnah Brurah brings the Meiri that the reason is because one must not make a Keli.
On the other hand, the Gemoro says that according to Rebi Eliezer, Kipul Eino Mo'il, so it is still a Beged, and as he lights it, it becomes a "broken Beged", i.e. Shever Keli, and he continues to light this Shever Keli.
Now, if the wick is a keli, it appears that before lighting, it is both a Beged and a wick. After lighting, it is a "broken Beged", but surely it is not a Shever Keli as far as the wick is concerned. Why can he not continue to light using the wick?
Meir Eliezer Bergman
A very nice Kashya!
Tosfos 47a DH 'Hanach' specifically refers to a whole (usable) wick (as opposed to Shivrei Pesilah) as a K'li.
What we need to understand is, why one may not kindle with a broken Beged? You think that it is some intrinsic Din of only being permitted to light with a complete K'li, but not with a broken one; but that is not the case.
The reason that one is not permitted to kindle a broken K'li is because it is Nolad (Muktzah, as the Bartenura explains) - in which case, even if it becomes another k'li, it is still Nolad (it is no worse than a non K'li that becomes a K'li on Shabbos, which is Nolad too).
Consequently, according to R. Eliezer, after lighting the folded piece of Beged, it becomes a Shever K'li, and is therefore Nolad, and one may not kindle it further (even though it has now become a wick).