On 10/15/2012 11:13 AM, Existential Angst wrote:
Assuming they are still dry, of course. A local home center guy said yes,
prolonged exposure to air renders it unusable.
How old is old? How to test? My own little spot tests (small mounds on a
board) are really crumbly, but I haven't compared it to fresh stuff yet.


I'm not a super expert on concrete and mortar but I've used enough over
the years to find that it's hygroscopic and will absorb moisture from
the air if it's not kept sealed up. When I was installing automatic
doors and store fronts, I used a lot of QUIKRETE® and self leveling
cement for thresholds and such so I kept the stuff in 5 gal buckets with
snap on air tight lids. ^_^

TDD