YD 120: IMMERSION OF UTENSILS
A Jew must immerse in a mikveh, with a blessing, any metal and glass food utensils purchased from or through a Gentile. Thus, a convert who immersed and converted should also immerse their utensils with a blessing. Others disagree and rule that as utensils that have been the valid utensils of someone who is now Jewish, they do not require immersion. Although the first view makes more sense, a convert ought to immerse these utensils but without a blessing with God’s name, since a number of authorities rule that no immersion is needed. Alternatively, the convert should purchase a utensil that requires immersion with a blessing and immerse all of their utensils at the same time. Rabbi Yitzchak Yosef proposes a further compromise: metal utensils, which require immersion as a matter of biblical law, should be immersed without a blessing while glass utensils, which require immersion only as a matter of rabbinic law, need not be immersed.
The most logical explanation of the view that one need not immerse utensils upon conversion is found in the writings of Rabbi Asher Weiss who presents two competing arguments in favor of non-immersion of utensils.
First, however, he concedes that the most halachic authorities agree that immersion is required. He states:
In truth, I repeat that I know that most great and wonderful halachic authorities agree that a convert needs to immerse his untensils. Such I heard from the lips of Rabbi Yosef Shalom Elyashiv shlita, and Rabbi Chaim Kanefsky shlita and such is written in Shevat haLevi (4:92) and Teshuvot Vehanhagot (1:249) who all state that the convert immerses with a bracha; see there.
Rabbi Weiss then notes his disagreement based on silent precedent:
However. I have always felt in my heart, now and in the past, that since we have not seen this halacha cited in the rishonim and the poskim of the prior generations, we have no better proof than this that a convert need not immerse his utensils. This is not a case of a specific incident, rather this matter is relevant to every single convert who has ever converted. From the silence of the decisors of previous generations, we see that they did not require such. I have cited in many cases that which the Chazon Ish states (Shave’it Chapter 7, page 218) that in such cases that silence of the poskim is the “resolution superior to all other proofs.”
Finally, Rabbi Weiss explains the substantive rule:
As to the substance of the matter, it appears that the whole idea of immersing utensils is limited to cases where the utensil is transferred from owner to owner through a conveyance of title. When the utensil transfers from the title of the Gentile to the title of the Jew, that is when the duty to immerse applies, as is simply noted by the Tur and Shulchan Aruch in YD 120:1 which states “One who purchases new utensils from Gentiles”. Such is not the case for a convert after conversion whose ownership of his utensils has not been abrogated and the utensil and not been transferred from one person to another. Thus there is no mitzvah to immerse the utensils [of a newly converted person].
This approach inclines one to rule (as Rabbi Weiss notes) that it is better for a convert to immerse untersils without a bracha.