Keilim 3:3-4
Keilim 3:3
Let’s say that a jar was purified by piercing it, then repaired by sealing the hole with tar, after which it was broken. If the part that was sealed with tar can hold a reviis (about 3 oz.), it is susceptible to ritual impurity because it hasn’t lost its status as a vessel. If a pottery shard was purified by piercing it, then repaired by sealing the hole with tar, then even if it can hold a reviis, it is not susceptible to ritual impurity because it has lost its status as a vessel.
Keilim 3:4
If a jar cracked and was repaired by coating it with dung, it is susceptible to impurity because it hasn’t lost its status as a vessel; this is so even in a case where removing the dung would cause the pieces of the jar to fall apart. If the jar shattered and he glued pieces of it together, or if he brought other pieces and sealed them together with dung, it is not susceptible to ritual impurity because it has lost its status as a vessel; this is the case even when the pieces would stay together after removing the dung. If one of the pieces would hold a reviis, then the entire vessel is susceptible to ritual impurity by being touched but only the part facing it is susceptible to ritual impurity through its airspace.