What would be the problems with the mesh tallit katan? I have heard several things:
1.) Since it’s not made of wool or cotton, it’s patur from tzitzit.
2.) The many holes in the mesh material invalidate it as a beged.
3.) On Shabbat you would be forbidden to wear a mesh tallit katan, because it’s not obligated in tzitzit.
Would you be allowed to make a bracha on such a tallit? Why or why not? I would assume not if it’s chayav of tzitzit.
Essentially all garments need tzitzis, even if they are made out of materials other than wool or linen. It is controversial though if they need tzitzis m’dorayso (opinion of the Rema) or only m’rabonon. The Mishna Berura concludes that it is therefore preferable to wear tzitzis made of wool in order to do the mitzvah according to all opinions on a d’orayso level. The exception to this is a leather garment. The reason being since it is not woven from different strands, rather it is already a whole piece. There is controversy among the poskim with regard to garments made of synthetic materials, (nylon, rayon, polyester, etc.) which are made from crude oil. Some poskim (including R’ Moshe Feinstein zt”l) say that it is not chayiv in tzitzis. other poskim conclude that if the garment is made from threads that it needs tzitzis, but if it isn’t made of various strands, even it appears that way then it should not be used for tzitizis. According to the poskim that we cannot put tzitzis on them we may not walk outside with such a garment (that has tzitzis on it) on shabbos, nor may we make a bracha on them.
Aside from this, there are poskim that say that the fact that it is made of a mesh material is another controversial issue, since it isn’t a garment that one would wear to cover himself in public.
Regarding making a bracha in such tzitzis, even if someone is going to wear it, he should not make a bracha on it.
O:CH 9-1, 10-4, M:B 9-5, 10-11, Aruch Hashulchan 10-9. Regarding polyester the osrim Igros Moshe O:CH 2-1, Shut Mahari Steif 28,, Kovetz Teshuvos (don’t make a bracha on it), Har Tzvi 1-9, Oz nidberu 7-53, , Halichos Shlomo Tefllah 3-16, permit it if it is made from threads. Divrei Yatziv 1-3, permits it in all instances. Regarding if it is made of mesh, see L’horos Nosan 2-2 that says that it isn’t kosher for tzitzis, whereas Oz nidberu permits it.