If the mortar is setting off too fast, then use cold water to add to the mortars. Or when all else fails just mix smaller batches of mortar at a time, enough to cover the area that will not set up too soon. Also make sure the surface you are adhering to or the tile you are grouting isn’t too hot. Cool it down.

How do you slow down a concrete setting?

Spray the concrete with the hose. Apply a light spray over the entire surface. Let the water dry and repeat. Spray the concrete repeatedly over a period of several days to slow the curing process.

What is the setting time for mortar?

MORTAR CURE TIME Mortar typically will cure to 60% of its final compressive strength within the first 24 hours. It will then take about 28 days to reach its final cure strength.