Sealing new pop up sink plug

boardtc

I'm way outside my comfort zone having dismantled a seized popup sink plug. I got a new one on Screwfix and fitting it was grand .. but I need to seal it.

I'm wondering about where to put the plumbers mait on this sink. On the picture the black plastics piece is a slip on which can go tight underneath. Would you recommend putting the plumbers mait above it or below it (and then adding another poly washer)?

Wearb

Put the putty at the top side, the side where the plug normally goes. Put a pencil sized ring of it underneath the lip, between the fitting and the sink. Tighten from underneath. Remove the excess from the top and retighten a bit more.

boardtc

Thanks very much. I just did that but water dripping underneath:

Wearb

Perhaps there's an overflow built into your sink and fitting.

septictank

Silicone or putty like Wearb said around the bottom of the sink where the black rubber ring is and some PTFE tape on the metal threads the screw joint.

Check just to be sure that there is a rubber ring seal inside the plastic waste connection, can fall out but as there is water in your picture above that connection I doubt it.