[If] one cut [the oven into] segments along its width, [each segment that is] less than four handbreadths is tahor. [If] one plastered it with clay, it becomes susceptible to tumah from when he heats it enough to bake sponge cakes in it. [If] one distanced the [clay] coating from it and placed sand or pebbles between them, of such [an oven] they said: A niddah and a woman who is tahor may bake in it and it is tahor.

An oven that came in pieces from the artisan’s workshop, and he made hoops for it, when he puts them on [the oven] it is [still] tahor [and then] it is tamei. [If] he removed its hoops, it is tahor. [If] he returned [the hoops] to [the oven] it is tahor. [If] he plastered it with clay it becomes susceptible to tumah, and he need not heat it, since it was already heated.

[If] one cut [the oven into] segments and placed sand between the segments, R’ Eliezer rules [it] tahor, but the Sages rule [it] tamei; this is the oven of the [coiled] serpent. Arabian cauldrons that one digs in the ground and plasters with clay: If the clay can stand on its own, it is tamei, but if not, it is tahor; and this is the oven of Ben Dinai.

An oven of stone or of metal is tahor, but [the metal oven] is tamei as a metal utensil. [If] it developed a hole [or] became damaged [or] cracked [and] one made a [clay] coating for it or a supplement of clay, it is tamei. How large must the hole be? [Large] enough for the flame to pass through. And the same applies to a stove. A stove of stone or of metal is tahor, but [the metal stove] is tamei as a metal utensil. [If] it developed a hole [or] became damaged [or] cracked [and] one made feet for it, it is tamei. If one plastered it with clay, whether on the inside or on the outside, it is tahor. R’ Yehudah says: On the inside it is tamei, but on the outside it is tahor.