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Old 12-29-2011, 11:44 PM
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Practical Q's on Plumber's Putty, Dope, Tape

A few questions why a new bathroom drain assembly may be leaking either at the drain's flange or from the (underside) nut. Note: I've researched this well via Google leading me to Youtube demos and various boards, like this one, but these questions remain unaddressed, or not fully answered:

a) Plumber's putty (for the drain flange) does not say how long to let set before wetting. Can it get wet immediately and work fine? Also, is plumber's putty known not to bond to some surfaces, such as vitreous porcelain which is very smooth? (After re-doing all my work the first time, it seemed the plumber's putty squished out down the drain making me wonder if won't bond to some surfaces.)

b) The nut in the drain assembly (beneath the sink) has been tightened to the point where I dare not go any further (to avoid causing damage). The male threads are coated in teflon tape. Would plumber's dope work better? Online plumbing advice says dope, not tape, on a drain. Is that the convention? Why?

Thanks in advance... Just Plumbing the Straight Dope on plumber's dope!
Old 12-30-2011, 01:52 AM
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Join Date: Feb 2008
Location: Chicago, IL
Posts: 10,970
Quote:
Originally Posted by Jinx View Post
A few questions why a new bathroom drain assembly may be leaking either at the drain's flange or from the (underside) nut. Note: I've researched this well via Google leading me to Youtube demos and various boards, like this one, but these questions remain unaddressed, or not fully answered:

a) Plumber's putty (for the drain flange) does not say how long to let set before wetting. Can it get wet immediately and work fine? Also, is plumber's putty known not to bond to some surfaces, such as vitreous porcelain which is very smooth? (After re-doing all my work the first time, it seemed the plumber's putty squished out down the drain making me wonder if won't bond to some surfaces.)
You can use it immediately. The thing about Plumber's putty is to use a LOT more of it than you think you need. Roll it into a tube, put it around the hole, overlapping the ends, then press down the drain flange. A lot of excess putty will squirt out both the top and bottom, but it does not matter. Collect the excess and put it back in the tub.

Quote:
b) The nut in the drain assembly (beneath the sink) has been tightened to the point where I dare not go any further (to avoid causing damage). The male threads are coated in teflon tape. Would plumber's dope work better? Online plumbing advice says dope, not tape, on a drain. Is that the convention? Why?
My brother the plumber is a fan of both Teflon tape and dope.
Old 12-30-2011, 01:56 AM
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Join Date: Jan 2010
Location: Norfolk, VA
Posts: 1,081
The purpose of plumber's putty is to form a water blocking seal as opposed to a bond and sticking to a surface is unnecessary. Actually, if it did form a bond this would make it more difficult to remove later when time arrives to replace a component. There is no wait time after the putty has been compressed and should stay flexible for many years.

On the drain nut, I presume it's still leaking after tightening but it's difficult to answer your question without knowing what specific fitting you're using. Some have rubber washers and others plastic compression fittings and usually neither teflon tape or plumber's dope are needed for a drain line but some apply it for a little 'insurance'. If you have a round plastic washer it should be tapered and you may have inserted it onto the pipe backwards. Look closely on the inside of this fitting and you should see a matching taper to tell you how the compression ring should be inserted to form a tight seal. I recommend trying a new plastic washer because the old one may have been damaged/deformed.

Finally, if you use tape, make sure you wind the teflon tape onto the threaded fitting properly. As an example, with the threaded fitting in your right hand, wind the tape tightly with your left hand moving clockwise (as seen by someone standing to your left) using about 3 layers of the tape onto the threaded fitting. Winding the tape in the opposite direction can cause it to unravel when attaching the fitting leading to a potential leak.
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