I am trying to set a fence post by the house to fix up a gate door. The usual "bag mix" for this job is a mixture of quarter inch stone and cement and lime. However, I also have a bag of type S mortar that I haven't used and would like to use or be rid of. Would it be compromised or ineffective to use some stone and type S mortar to set the fence? or is there too much sand and lime in the mix?