I recently bought a Pegasus granite sink from Home Depot. I also bought the
matching drain made by Watts. The instructions for the drain (which is part
plastic) states "DO NOT use an oil base putty - it may cause discoloration".
I am assuming this is because of the plastic. But I have also discovered
from the labels of several brands of plumbers putty, that it should not be
used on marble, granite and other surfaces. This sink is real granite. It
is 80% crushed granite and 20% resin. After talking with numerous hardware
people, the recommendation was to use caulk. I used DAP Kitchen and Bath
Adhesive Caulk and let it sit for two days before using the sink. The caulk
is not working and my sink is leaking. Is there a water based plumbers
putty? What else can I use? I am not as concerned about the plastic drain
as I am about the granite sink. If there is a sealant that is safe on
granite but not on plastic, I will replace the plastic drain with a
stainless steel drain.