How can I make a facial mold?

I would like to make a cast/ mold of a face to make a life like mask of my kids faces. Are there commercially available material kits for doing this? Any help/ tips appreciated.How can I make a facial mold?
Done this many times.You need plaster of Paris,Vaseline and some straws.Mix the plaster to a fairly thick consistency,smear the persons face with Vaseline, make sure the eyebrows get a fair share.Start to spread the plaster, leave the nose area till last, put the straws into the nostrils have the person hold them,some people can get a little panicky. Now wait till the plaster dries, it depends on how much plaster was used, if it takes too long to set start over and use more plaster. Good LuckHow can I make a facial mold?
Craft stores sell ';paper mache'; strips - gauze strips that are coated with a powdery substance that become sticky and very flexible when wet. You can cut the dry strips into any size or shape; triangles (rather than strips or rectangles) are easy to shape on a 3-D surface. I recall seeing instructions on the package for making a mask, and I think that you'd have to protect the skin first by applying cold cream. Depending on the age of your children, I'm guessing that the hardest part will be getting them to sit still!! Good luck!