Can air-dried earthenware become tamei?

Question

According to mishna Keilim 4:4, earthenware is not susceptible to tumah until it has been baked in an oven.

‮כלי חרס מאימתיי מקבלין טומאה? משייצרפו בכבשן, והיא גמר מלאכתן.

When does earthenware become susceptible to tumah? From when one bakes it in an oven, and this is the end of their manufacture. (translation partly from Kehati)

Nowadays, one can purchase air-dried (or self-hardening) clay, which is clay with some additive to make it harden even without firing.

Are pots made from air-dried clay susceptible to tumah? Do they have the status of earthenware vessels (כלי חרס), and so are not susceptible as long as they aren't baked? Or perhaps since the completion of their manufacture does not involve an oven, they are susceptible to tumah as soon as they're ready to be used?

Answer 1

The question is if a glue that is strong anough to make them utensils give them a status of Keli cheres despite they are not baked. Maybe that we have a proof that it is not the case from the Mishna 11.4.

וְכֵן מִן הַחֲלָמָא וּמִן הַגְּלָלִים.‏

And similarly for a mixture of white earth and dung that plays the function of glue and is itself a material from which one can make an utensil (with a special status), ...

Rambam explains in his comment:

וכבר זכרנו ג"כ שכלי גללים לא יטמאו. וחלמא טיט דבק לדמיון לובן ביצה ולזה יקרא חלמא כמו אם יש טעם בריר חלמות וכאשר נתערב הטיט בגלל ונעשה מקבוצן כלי מבושל והוא מעורב מכלי חרס וכלי גללים:‏

We already taught that utensils made from dung wouldn't be Unclean. "Chalma" is a white earth... When there is a mixture of Chalma and dung, from which an utensil is made, when the utensil is baked, this utensil (that is now baked) is a mixture of Keli Cheres and Keli Galalim. {explanation, before the baking it was surely not a Keli Cheres, even if the majority of the mixture is Chalma. But after baking, the Chalma reaches a status of Keli cheres, then, if it is the majority, the status of the utensil will be Keli Cheres.}

We can learn from this that pots made from air-dried clay are not susceptible to tumah before baking.

Answer 2

Rav Ovadia M'Bartenura writes (ibid):

(Source from Sefaria)

משיצרפם בכבשן. וקודם צירוף הן כלי אדמה ואין מיטמאין

When they are baked in the oven: And before this baking, they are earthenware [i.e. not clay] vessels and are not suseptable to Tuma

Based on this, air dried clay vessels would not be susceptible to Tuma.

Hope this helps!