I need some tips for dry fitting pvc before glue. Seems easy enough but I have issues.

Should I be inserting them all the way? In most cases I cant do this or if I think I have it inserted all the way I cannot easily remove them or when I apply glue it pushes it in even further.

What is the proper technique? seems my drains always end up just a hair or two mismeasured because of my dry fitting.

Measure properly, do NOT try to dry fit it.

I've always dry-fitted pvc, and put orientation marks on the fittings and pipes. I've never had a problem assembling and dis-assembling with a twist. I'm no plumber, and getting an offset right by measurement alone, just wouldn't work out well for me.

I never dry fit, I allow 1 1/2" for a 3" fitting hub, 3/4" for 2" + 1 1/2".

As a DIYer, I dry fit for the most part to get the orientation right, and use a marker to mark on the hub and pipe precisely where to align the two pieces. I don't try to push it all the way in during dry fit as all I am concerned with is the rotational aspect. For example, I learned from here if you roll up a wye 45 degrees and insert a 60 degree elbow into the branch you will get a perfect 90 degree turn out of it. On length I just measure from end to end and add in the two socket depths.

Good plumbers measure center to center and then deduct for the fitting.

Dry fit if you have no chance for screwing up because you only have the fittings needed...for 1 1/2 and 2" pipe if you chamfer the PVC it allows for dry fitting and requiring little strength to pull it apart. Yes, a sharpie is your best friend for marking pipe and fittings. Doesn't make sense though if you are not a plumber to invest in a chamfering tool.

Time is money. While there is nothing wrong with dry fitting, I think you would find that the guys doing this day in and out do not dry fit.

As a foreman of 20- 30 guys I can tell you when I catch a guy dry fitting I throw a fit. To many times a guy dry fits something then goes to break or lunch and comes back thinking it has been glued.

good point PP....

no visible primer should be a dead giveaway.

True--if it's a requirement within said jurisdiction.

hj says: " Good plumbers measure center to center and then deduct for the fitting."

Why is that?

I would think subtracting the fitting distance is harder to do because different manufacturers like Charlotte, Lasco, Mueller etc...may have different dimensions to center of fittings?

Because measuring center to center first and subtracting the fittings is how it should be done. If you do it that way every time for any job, you will always have it right the first time. Any job may require any number of fittings of varying shapes and sizes. Unless you are doing rough installs and making 400 houses with the exact same plumbing, you won't be memorizing pipe lengths for particular sections. And if you were able to look at blueprints for Exact lengths, it just means that someone already did the same math. Anyone that does quality work will use measurements; it should never be a case of "I have 3 feet of pipe, let's put it here and see what we can do with it".. unless it is 'art'

Even if they did, which is not likely, you have the fitting in your hand so just measure it. In fact, you only need to do it once since they will be the same.

In fact, someone mentioned the Y rolled into a 1/6 bend which makes a perfect "rise and 90 degree branch". The "run" piece between the two fittings is MUCH easier to calculate when using center to center dimensions rather than "cut and fit".



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I was the one who mentioned the rolled up wye with a 1/6 bend. You were the one who taught me that two years ago in this little project where I had to wet vent the tub.





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Two years ago and still no tub?

KCRoto that's a two year old pic!

lol, ok, thought you went downstairs and snapped that. I wouldn't have kept a picture of the pipes.