[HDowse]

Hi Ed, I don’t have specific info on the TCP primer but every primer I’ve used does settle and needs quite a bit of stirring. You can buy a rig that goes in a drill that helps a lot. If you’ve used one you know not to raise the unit out of the paint while the drill is running.
Also, I often take an old can of primer or paint to my local hardware store and they put it in their paint shaker upper rig. As far as shelf life it’s probably just fine but others will chime on.