Retarding Plaster (with lime Putty)

[JohnD]

I have a friend over from Australia, who is renovating his 1850's house. The walls are brick which he gives a scratch coat of Lime/sand mortar; a level coat of lime/sand, and a final skim of mixed lime putty 50% and "hardwall plaster" 50% (there is not much variety of plasters available over there as this is not a common finish).

He finds the skim finish sets in about 10 mins from mixing, and asks if there is a way of retarding the set. The temperature (South Coast) in not high, about 15-20C

 

[Third_Eye]

I have heard if u leave a big bucket full of water in the middle of the room that this slows down the drying process, but all windows must be shut and doors.