PREPARING THE POSITIVE

Putting that first piece of clay onto a lifecast to create something new is a great feeling. But first, there is a bit of cast preparation to do. I will presume that your lifecast positive has been cleaned up—minor imperfections repaired and edges smoothed and rid of any roughness. Often it is necessary to brush a very light layer of petroleum jelly over the surface of your stone positive, then rub it into the surface; this will help the oil clay adhere to it. Make sure that there is no dust left over from your cleanup of the positive before you apply the petroleum jelly. If there is, wipe the cast with a damp cloth or paper towel to remove dust or tiny pieces of Ultracal that might mix with the petroleum jelly and make a gritty or otherwise yucky surface.