Damien,
My father was a tradesman Plasterer, he told me years ago that the set speed can be, sped up or slowed down. Using milk & Salt. the problem is i can't remember which is for what.
Salt (it's inorganic) speeds up the setting time. Years ago I made some experiments, and I don't recommend using it. If you use too much, the dried plaster tends to crack, and if you use not enough there is no apparent reaction. There's no use to bother with it.
Vinegar and milk (both are organic!) slow down the setting time. Again take care with the amount: Too much of the stuff and the plaster doesn't set at all.
Like David I would suggest to vary the setting time by mixing more or less water with the plaster/Hydrocal powder. Pancake batter consistency is a good rule-of-thumb :thumb: for covering larger areas; for rock or masonry wall castings mix it stiffer, like mud in a drying-out puddle.
cpNscale,
I usally have to apply it with my hands which is very messy.
Once you have really started covering your layout with a landscape shell, handling this messy stuff can become outright funny!
Just be sure to cover the floor with newspapers - and don't wear your best clothes for that occasion.
Ron
