I've just heard that it's a no no.. to mix putty with plastics so I dont do it... I've read on a abs p.o plug dont use it... maybe it doesn't really attack it but if the putty is a petroleum product and plastic is a petroleum product there is a possibility there is some reaction...
Correct, there is some reaction but it isn't enough to cause damage or we would be seeing failures indicating such in the field. If anything it helps the putty seal in my opinion.
There is a guy at work never uses either... like obviously there are some things its needed for but.. he just says the rubber is what seals the basket strainer..
Now we've had this conflict before and he says rubber goes on bottom I say top... i dont know anymore because other guys say the top aswell but I trust him... whatever he does it works never have had a call back to fix his things plus hes been doing this work for 40 years plus... he said 2020 will be 43 years for him.. just an addition to stir pot lol..
The large rubber seal for a basket strainer goes below the sink. Mind you there are two(most common) types of basket strainer and this is true for both. One has a small nut and no fiber washer but does have a rubber washer. The other has a large nut with a fiber washer and then rubber.
I guess neither has to have putty(or silicone) as when you squish the rubber washer it should expand in as well as squishing out and thus seal against the basket. I have never relied on this and don't really want to. Either way the putty(or silicone) is mainly there to fill the small gap under the lip of the strainer so no food sticks in there and rots. It also makes a seal.
Not using putty(or silicone) on a pop-up seems fine except again for the issue of stuff getting in that gap like soap and rotting or corroding the metal. The rubber washer has to make a seal whether you use putty(or silicone) or not because the holes for the overflow are there.
Honestly now that I think about it I am questioning if putty(or silicone) is really needed at all on sink baskets or pop-ups. I know that every plumber I have worked with has used putty and every one i have taken apart even from 80 years ago has had putty. But the more I think about it the more I can see how putty(or silicone) isn't really needed.
I feel like these putty(or silicone) posts need to be moved to a dedicated thread where we can debate this subject.
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