which class did you attend?
the mixture for "practice lime putty" - the one that is done from construction lime should be as thick as possible as you mix it, you need a drill - heavy duty one, you will burn out the cheap one.
You should not look for high calcium hydrated lime and better off with Type-S construction lime for practice lime putty. When you get comfortable get good slaked calcium fresco putty.
The reason being is that high calcium hydrated (dry) lime is produced for agriculture and it is very much inert due do the process. I will take forever to set and it will feel wet also.
before you scoop, you should drain the water from the top of the putty and mix at least 2qarts of putty to 4quarts of sand.
if mix is still too wet, put it into the bucket and cover with plastic, just lay it over the plaster and tuck the ends around.
in a couple of days access water will separate - pour that water out, collect with a sponge i needed.
remix, you should be ok.
go to www.frescoschool.org and register or simply put you name on Only Fresco list there.
at the end of this month we will be pre-releasing first video "Fresco Plaster" of Buon Fresco Foundations - Video Set (5 videos)
learn fresco at http://FrescoSchool.org
fresco painting video tutorials: http://www.FrescoSchool.com
Fresco School Video Channel
Contemporary Fresco Gazette
commission fresco or mural http://iLAdesigns.com
Contemporary Fresco Painting Resouce Center