Hi Barbara, I found some information for you....I hope it is of help.It's about repairing chipped cookware, not sure if that's what your issue is, but even if not this may help you.
What is the enamel on? A photo would help.
Do you have a picture of what is cracked? is it an appliance? If so they sell appliance repair.
here's a great post on enamel repairs.
Enamel on what?