New bath waste not sealing

[tonton]

I think the single rubber washer the new bath waste came with is not thick enough to take up the space between the bath and the flange of the new fitting as the recess of the bath's hole is quite deep, so it's not sealing well. The previous waste had been fitted with a lot of plumber's putty. What is the best way to get it to seal?

I've attached a pic of the washer on the bath and the type of waste fitting I'm using.

 

[denso13]

I don't unless I have to but you might need some silicone on the washer or plumbers mait.

 

[Madrab]

The water tight seal isn't normally created on that side of the waste - it's usually created on the underside of the waste by the thick washer in between the nut and the bottom of the bath.

If there is a weep underneath then ensuring the base of the bath at the waste hole is nice and clean and flat then take the nut and the washer off, a little bead of silicone where the body of the waste meets the underside of the waste hole of the bath and then refit the washer and nut. Then as hand tight as possible and an extra half a turn with grips should do it. Leave it 1/2hr then test.