FItting Strainer Trap in Kitchen Sink

[wytco0]

Hi All I bought a new Strainer Waste for my kitchen sink today (this one Strainer Waste ) It came without a washer for the inside of the sink.

I can't reuse the old washer as its broken and B&Q don't seem to sell any suitable washers for strainer wastes?

What is the best way of fitting these? It must need some sort of washer or compound to seal it properly but screwfix say they don't know?

Thanks

 

[Burnerman]

Yet another candidate for a good squidge of silicone beneath the waste rose and the sink hole......don't underdo it!
John