Recently my wife and I replaced the sink in our kitchen with a two bowl stainless steel sink. When we ordered it from our local plumbing shop its description said that it was soundproofed, but when we received the sink we discovered this was stretching the truth a little bit, as the “soundproofing” consisted of four thin rubber rectangles glued to the bottom of each bowl (see the second photo).
Like any good nerd, I searched the Internet for a better solution and found many, including from spray on foam, automotive undercoating, and pickup truck bed liner. All of these solutions required careful masking, followed by a generally messy application of the product – all with mixed results. I am happy to say that the product that I used requires no masking, is easy to apply and works wonderfully – if you tap the inside of our new sink all you will hear is a dull thud.
What I used is 3M Automotive Sound Reduction Mat, a self-adhesive, flexible mat that is designed to reduce road noise and vibration. It is often applied to the inside of the door panels when installing automotive stereo systems, but it also works great on stainless steel sinks. You can find the 3M or equivalent product at most automotive supply stores or from a car stereo shop. The 3M product is a semi-stiff sheet about an eighth-inch thick with a black shiny finish and a diamond pattern. It is self-adhesive, protected by a peel off backing. For me, it came two sheets to a box, which was enough to do one bowl so I purchased two boxes.