If I recall correctly the rule of thumb has been to toss it after 48 hours or so. But why? I've found that especially if kept indoors, the stuff seems to be good for months and months later. As long as it keeps its same consistancy and doesn't try up... what else happens that causes it to be useless?

Is it possibly just the ZFX effects that are compromised but not the Z2 itself? If so then it's still useful as long as you don't intend to do more than one coat a day and already have a base coat down, right?

A few days ago I was going to apply Z2 to my wife's 4runner and I realized I had left a couple of 1/3 full 2oz bottles w/ ZFX already mixed in and I didn't want them to go to waste.

So did I waste my time? Will the durability or shine not be as good? It was obvious (visually and tactilely) freshly waxed. I don't know if the shine was as absolutely great as it could have been with 'fresh' Z2, but if it wasn't, it was close enough that I couldn't tell.

 

Usually if air is allowed to mix into the Z-2/Z-5 - ZFX mixture it will thicken up over time, having said that there are many times where I have used less than the amount I mixed up, and many time a week or two later I apply it to something, and it's still ok. What happens is the ZFX will break down over time when mixed with the polishes, so I add a few more drops of ZFX and all is good. I would not make a habit of mixing over 1 oz at a time, because over time it will not always stay liquid, and mixing up a batch only takes a few minutes.

 

I did not add anymore ZFX but from what I understand the 'more expensive than liquid crack' ZFX serve no purpose if if you've already applied your first coat and don't intend to apply a second coat in the next 24 hours. Right?

 

Not really, with ZFX added to the Z-2 Pro and Z-5 Pro, you will get a brighter and a harder finish, can you or I see the difference, probably not, but you will lose "some" durability, not a big deal for garage queens, but the daily driver many get less months of service compared to using ZFX.