Observing cracks in your silver layer is often caused by the overuse of reducer solution, which in turn causes the silver to flake off. The presence of grease on the substrate's surface can also cause improper adhesion and flaking. If this happens, make sure to remove the grease thoroughly with a good degreaser (#87) solution. If no grease is present, reduce your quantities of #87 degreaser and C-22 wetting agent used. If none of these factors are viable, it is possible that temperatures above 70F can sometimes cause this problem. If that is the case, increase your reducer dilution by changing it to a 1:30 (reducer to DI water) mix.