In article ,
blueman wrote:

HerHusband writes:
If your can of PVC cement is old, it's
probably gelled by now anyway.

Ok.. question... at what point does PVC cement go bad and not perform
well in "welding" a PVC joint. Obviousy if it is so hardened that it
won't coat the PVC, then it is bad. But what if it is just a bit
gelled (as in a little thick) but still is able to give a nice liquid
coating to the PVC? Will it still be just as strong?

I only occasionally end up using PVC so the cement and primer can end
up sitting around my basement for years. I do a good job of sealing
the cans tightly and then put them in air-tight plastic bags, so the
stuff does seem to stay fresh longer than one might expect -- on
principal, I hate to throw things out, but obviously, I would if
needed for an optimum weld.

Any thoughts?

"Just a bit gelled" is somewhat subjective, but I've used less than
perfectly fresh stuff successfully on many occasions. Most important
thing IMO is surface preparation. I carefully and thoroughly sand both
pieces with 180-220 grit to break the glaze. I know the primer is
supposed to do that, but then I've never had a joint fail, as have
several of my non-sanding friends. Also of course the rotation during
assembly helps distribute the glue evenly.