hairline cracks in mortor between fieldstone
by steve fenimore
I am jointing the fieldstone with a bakers bag, then cleaning the joint with a jointer and smoothing out with my finger and then brushing. It has been 85 - 90 degrees direct sun. I am noticing hairline cracks in the mortor. the mortor mix is type -S mortor with 1 part mortor to 2 parts sand one cup black dye. The field stone is layed over a 4" concrete slab and adheared to concrete with 3/4 to 1 1/2" portland and mortor base. what am i doing wrong that i am getting these hairline cracks?