ExactlyI had used clear silicone but the washer looked like it was squeezed out on the thin side so I took it off, the silicone hasn't really stuck to much.
Flat steel plate? What did I miss?Mait doesn't set, it will slowly migrate like Ikea sink sealer.
I would go with Kram's suggestion and add a waxed or cling filmed flat steel plate to keep the required flat profile
It is new but I've had it sitting here for months.
FWIW, if the top side is sealed properly, water should never get near the underside. The only time threads would need sealing is on a basin, where the overflow enters through the side of metal waste.
Do a dry assembly without the rubber washer which you are being advised to discard. That will verify that the threads on the strainer are cut long enough for the nut to tighten without bottoming out. If the nut won't tighten, a solid nylon or stainless washer could be needed as a spacer.







