What is consequence of bottoming out a fitting during dry fit for ABS?

DavidTu · Apr 7, 2014

ABS pipe is not supposed to bottom out during dry fit in fittings. However, if you dry fit a few times (for example to work out a complex geometry) or wiggle the pipe in the fitting a bit it seems like the joint often gets loose enough to actually bottom out, or nearly so.

The fittings are tapered and the tolerances are supposed to be pretty tight for the solvent weld to do its thing... in theory at least -- in practice I am wondering if there is much consequence to a pipe bottoming out in a fitting during dry fit. Is the concern that the joint will fail OVER TIME or will fail immediately (upon test)? If a rough-in is water tested with water through the roof and it PASSES is that proof enough that one escaped any consequence of bottoming out or is it somehow more insidious than that and it will fail, perhaps, some time later?

Jadnashua · Apr 8, 2014

If you read the ingredients in the cement, you'll usually see it also contains some of the respective plastic...this helps to fill in while the solvents melt the pipe and fitting to make the bond. Dry fitting is chancy, there's almost always a gap at the bottom of the fitting and that can mess up any carefully assembled system's final position. It doesn't have to be big to add up, and it can be a major pain to get a dry fitted joint apart.

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Gary Swart · Apr 8, 2014

This is why they invented tape measures. LOL

Terry · Apr 8, 2014

DavidTu said:
ABS pipe is not supposed to bottom out during dry fit in fittings. However, if you dry fit a few times (for example to work out a complex geometry) or wiggle the pipe in the fitting a bit it seems like the joint often gets loose enough to actually bottom out, or nearly so.

The fittings are tapered and the tolerances are supposed to be pretty tight for the solvent weld to do its thing... in theory at least -- in practice I am wondering if there is much consequence to a pipe bottoming out in a fitting during dry fit. Is the concern that the joint will fail OVER TIME or will fail immediately (upon test)? If a rough-in is water tested with water through the roof and it PASSES is that proof enough that one escaped any consequence of bottoming out or is it somehow more insidious than that and it will fail, perhaps, some time later?

You're thinking way too much. Just glue it up.

What is consequence of bottoming out a fitting during dry fit for ABS?

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