How much engagement is enough?

hhcibtpaun · Mar 26, 2009

So, I have yet to master measuring all the lengths correctly, when assembling my pvc piping. I measure and mark, but it always seems like I come up short.

I am on my third rendition of a simple sink drain and on the last piece I get about 1/4" of engagement between the pipe and the 45 connector I am using? Is this enough? I plan to pressure test, then it will be sealed into my slab...

I can redo it if it is 100% necessary, but if it is acceptable I will leave it, and move on.

So is 1/4" of engagement acceptable, or should i go for 1/2"...Thoughts???

Thanks...Mike

Nate R · Mar 26, 2009

You want full engagement. There's a certain amount of bonding area needed for a strong joint depending on the fitting diameter.

PVC can be a bit tricky because you can't dry fit it and use those lengths. The solvent actually partially melts the plastic and fuses 2 pieces into one. So, you can't insert them all the way together dry, usually. But when you go to glue them, they slide in all the way. You have to account for the full depth of the joint when you measure.

I'm not a plumber, so let one of them give their input before you do anything.

Sponsor · 2022-01-29T12:20:58-0800

SewerRatz · Mar 26, 2009

The pipe cut needs to be square, and a debured on the inside as well the outside and needs to fully engage the fitting.

NHmaster · Mar 26, 2009

1 1/4", 1 1/2" and 2" fittings all have about a 3/4" engagement. 3" and 4" have 1 1/2"

Redwood · Mar 26, 2009

Apply primer to both surfaces, Go over it several times with the swab you want to see the pvc actually clean up...

Apply cement to both surfaces and twist it back and forth as you assemble it. Then hold it until it sets up or it will push off...

You want full engagement. If you can't get it you are doing something wrong...

hhcibtpaun · Mar 26, 2009

OK...I will redo it...When I get the primer and glue I can get full engagement...I just end up cutting the pipe a little short...I will try again...Thanks for the input...

Mike

99k · Mar 26, 2009

Practice makes perfect ... you need to do a little metal math when dry fitting and make a compensation because the assembly will shorten once it is solvent welded and fully seated in the hub.

hhcibtpaun · Mar 26, 2009

99k said:
Practice makes perfect ... you need to do a little metal math when dry fitting and make a compensation because the assembly will shorten once it is solvent welded and fully seated in the hub.

Yeah I have been doing that, but I think now I will just measure the distance between fittings, then add 1 1/2"...It's killing me because this is a nice simple run....I did the drain on the tub which was all convoluted and that worked like a charm....

At least I am getting close to being done....

Thanks...Mike

hj · Mar 27, 2009

engagement

The ONLY proper engagement is completely into the bell of the fitting. That is the ONLY way to insure that the interior of the line has a smooth flow. Poor engagement creates "valleys" between the end of the pipe and the bottom of the bell.

How much engagement is enough?

hhcibtpaun

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Nate R

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SewerRatz

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NHmaster

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Redwood

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hhcibtpaun

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99k

Radon Contractor and Water Treatment

hhcibtpaun

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hj

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