Compared full strength to full strength, the answer is NO. Actually they stay wet longer. If an adhesive must be cut with water for it to flow in a paste machine like Roman’s or Gardner’s clays, the added water will extend dry time, BUT job failure is a very high risk. Why? Clay adhesives are formulated with less water for use with wallcoverings that tend to bubble, curl at edges/seams. Cutting a clay paste with water will almost guarantee problems.