Mortar Shower Pan Timing Question

[digitalsam]

Hello, We are converting a tub to a shower and have questions about curing times.
I put down the first layer of mortar to create the slope and am about to lay down the PVC liner and put up the cement board on the walls.
My question is: when I put down the second mortar layer, how long do I wait to tile? I have read that you have to do it within 16-24 hours or the mortar enters a "green" stage and you can't tile for 28 days? I have also read that you should wait 3-4 days. There is a lot of differing information out there.

Thanks for any input you all have.

 

[Jadnashua]

Other than to wait long enough for things to firm up so you can work over it (generally, overnight is okay but don't put something like a ladder on it!) pretty much when you get to it. There's enough texture to a mud pack that the thinset will get worked into the pores when you spread it out prior to adding enough again to notch it for setting the tile. It doesn't hurt to wipe it down with a wet sponge prior to spreading the thinset. It's not too wet unless there's liquid water standing in/on it. That keeps the thinset from being sucked dry and changing its texture and maybe depriving it of the moisture it needs to cure. Curing cement is a chemical reaction initiated by adding the water...water literally becomes part of the cement and any excess evaporates.