Mandinca
Member
I know this is an old post, but I wanted to comment because I had the same struggle making this Delta 400 tub drain seal correctly. I agree, the Delta instructions are POOR regarding the drain. As everyone mentioned, beneath the tub there is a layer of black plastic, and there's an air gap between the two layers where the drain passes through. First attempt, mine leaked like crazy. I had only sealed between the drain and the top side of the tub, which is normal; but with this application, the water made its way back up the threads and leaked between those two layers.
My solution was to put a thick bead of plumber's putty (non-petroleum based for the acrylic tub) between the drain and tub, AND ran a thick line of Blue Monster Thread Sealant around the male threads. I let it sit for 24 hours before testing it, and it now holds perfectly. I hope this helps someone else, because it was incredibly frustrating!
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I have this exact same issue. Can you recommend a non petroleum based putty to use - whenever I search all I get is results for "non staining" rather than "non petroleum".
Also, Home Depot sells two versions of the Blue Monster, one with PTFE - which did you use ?
Lastly, your drawing shows blue monster in two locations....or is the lower location just representing where the threads will be when the drain is screwed down ?