# reducing pipe size for sink drain



## bluebee1314 (Mar 24, 2007)

I'm trying to install a pedestal sink in my bathroom. The drain assembly is 1 1/4 diameter, but the copper waste line in the wall is 1 1/2. (The house is circa 1939.)

I'm hoping to use brass/aluminum rather than pvc pipes. I have one set of each, a 1 1/2 assembly and a 1 1/4. How and where can I transition from the 1 1/4 sink drain to the 1 1/2 wall pipe? 

Also - this will be my first soldering job. I've practiced on scrap pipe, but if this is going to require a lot of additional soldering, I should probably just use pvc. 

Thanks!


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## Ron The Plumber (Jun 7, 2006)

There a washer 1-1/4 to 1-1/2 thats all it will take use it on the drain off the bottom of the sink, then use the 1-1/2" trap. Use the PVC trap for easy installation


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## bluebee1314 (Mar 24, 2007)

Thanks! Although finding one was a bit of an adventure.  Local place didn't have it, Home Depot knew what it was but didn't have it, Lowe's said there was no such thing (and didn't have it). So while staring blankly at the plumbing aisle at Lowe's, I discovered a chrome trap with 1 1/4 inlet and 1 1/2 outlet. There was only one left, and it was in the wrong place on the shelf, so I figure it was divine plumbing intervention. ;-)


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## Ron The Plumber (Jun 7, 2006)

That will work also, traps usally come with this washer in the package there wraped in.


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## Jantique (Nov 26, 2007)

*More plumbing joint questions! Thank you.*

On paper, the plumbing in my kitchen rehab seemed like something I could reason my way through doing, but it's the end of my first day of plumbing and I'm humbled. The seals at the joints are causing me to go searching on the net for answers. 

Just to be sure, that drain pipe reducing washer (from 1 1/2 to 1 1/4) is only used when changing the pipe size, right?

So when I connect two slip fittings together, no washer is used if the pieces are all the same size... right? And no purple primer with clear glue because those are the places I would need to unscrew to dislodge a clog or retrieve something that might fall into the drain. What about teflon tape and/or plumber's putty? 

And, when I insert the PVC pipe to be glued into a threaded end of a slip joint, how many inches should it go in to assure that it won't slip out?

And, are baffle connectors pieces a bad idea on a kitchen drain system? Seems like they would trap debris. I was going to use them to create a slight downward slope on the horizontals between the two basins.

If not a baffle connector, then should I use a heat gun to create a slight slope in PVC pipe? How do you get the joints to meet squarely when there's a slight downward slope? 

And for the air gap valve that will sit beside the faucet to vent the dishwasher, is it OK if the discharge line up from the d/w to the air gap is slightly smaller in diameter than the discharge line exiting from the air gap valve and going into the garbage disposal? What is ideal -- different or the same diameters? 

Thanks very much! Never realized how many decisions need to be made!


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## majakdragon (Sep 16, 2006)

I will attempt to answer as best I can since I can't "see" the piping. When connecting slip-joint pipe, the nylon washer is used. The flat side goes into the nut and the beveled side is outwards. This forms a seal in the threaded connection on the pipe. There are two types of nylon washers. One is for connecting same size pipes and the other is a reducing washer for going from 1-1/2" to 1-1/4" pipe. They use the same nut though, the body of the washer is just thicker to compensate for the size differences. No glue or putty for slip-joints.2) On the glued fittings, there is a "stop" inside the fitting being glued. It is about an inch deep depending on the size of the piping. Apply glue, after primer, and slip the pipe into the fitting. Give a twist to assure the areas are covered with glue. Hold for about 5 seconds to make sure it doesn't push back out. It won't move after that. On the sinks crossover pipe, since they are also slip-joints, just push the farthest side from the drain pipe, up a bit higher than the other sinks drain. (if it is not a slip-joint, cut the tailpiece that comes down from the strainer basket 1/8" shorter). Do not heat the piping to bend it. 3) Forget the baffles. 4) Are you sure you are required to install an air-gap? Many States that used to require them have discontinued the practice. The connections on the air-gap are two different sizes so you will need to purchase the tubing from the air-gap to the disposer. Hope this helps. Good luck.


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