How soon can I take the spacers out of wall tiles?

[Avocet]

I'm having a go at tiling my bathroom wall to about half way up. I'm using white tiles that are 220mm square and 8mm thick. They're going on to plasterboard that has been plastered for about 20 years. It was painted in white emulsion but I've sanded that off to bare plaster and painted a coat of "Primeplus" on it.

I'm using Tilemaster standard set "Setaflex" adhesive.

The reason I ask, is that there's some adhesive that has oozed out between the tiles and it feels quite hard and dry on the tiles but the stuff behind it (in the grooves) is still relatively soft. I wanted to scrape off the excess and sponge them down before it set too hard.

I'm working indoors in a very dry, modern house at about 20 degrees C.

 

[bobasd]

immediately clean off the face of the tile any squeezes out adhesive - dont allow it to harden.
and clean out the joins to allow grout.

you can temporary remove small groups of spacers and replace them after cleaning their joins. start at the top courses.
however, spacers can sometimes be totally removed after an hour or two - it depends on conditions.