In the other post I should have worded that it becomes inactive, using the phrase "stop" indicates permanently. Cure #1 is effected by temperature. The closer you are to 40° and staying in the safe zone the better the environment. As the environment gets colder, the rate that it converts slows. If you get below 36°F, it almost becomes inactive.
Cure #1 starts working immediately. In sausage, if you distributed the cure well into the meat, you can start smoking/cooking right away. For best distribution you should mix the cure with the water you will be adding to the sausage.
If my sausage doesn't have powdered milk or soy protein concentrate, I will let is sit over night prior to stuffing to let the flavors fully mingle and to ensure equal distribution of the cure. If I add one of the products I've mentioned above, I will stuff right after mixing, and smoke right away. If not the sausage may bind to tightly, and become difficult to extrude. Once stuffed if you like you can refrigerate overnight and then smoke.