Novel,

http://s349.photobucket.com/user/Nov..._0172.jpg.html
There seems to be a lot of questions regarding my 3" pipe.. I am the
OP here. Some said to measure with a ruler..I went a step further by
circling it with a string, than lied it down a ruler and it measured
6". So half of that, I believe would be the diameter...so do the math.
It was circled around the red tape area cause that is where it was
inserted into the T-pipe.

I'm terrible at math, so I used an online calculator to find the diameter:

http://www.onlineconversion.com/circlesolve.htm

6" circumference = 1.91" diameter

Then I looked up the outside diameter of galvanized pipe:

http://products.anssteel.com/viewite...ized-standard-
steel-pipe

1-1/2" galvanized appears to be closest to your 1.91" measurement.

That's a bit smaller than I expected. Dang, I guessed 2" pipe.

I knew it wasn't 3" based on the size of the bleach or vinegar bottle next
to it. The PVC tailpiece is usually 1-1/4 or 1-1/2, and the trap looks
larger than the tailpiece. The P-trap also looks like it reduces slightly
where it drops from the red taped area. 2" seemed the most likely.

I blame it on trick photography and/or photoshop.

It's one of those infinity photos where 3" pipe drains upward into a 1-
1/2" stack.

Thanks for clearing up the debate. Like trying to guess the number of
marbles in a jar, that was a fun side diversion.

Anthony Watson
www.mountainsoftware.com
www.watsondiy.com