Hand and Feet casting after 6 months of age

I know that it is recommend that you don't cast childsrens hand and feet from the age of 6 months to 2 years, but I have several people asking me to do it. I have been searching the internet to see if there is anything out there that will allow me to do it and I came accross a business in the UK that uses a material they call Magic Custard. The product sets in 5 seconds (approx.). Peels off children clean and easy(and it doesn't matter if your children wriggle!)

The name 'Magic Custard' refers to the exclusive casting method, which uses a specially developed form of alginate. The speed at which this sets enables highly detailed impressions to be taken quickly and easily with no discomfort to the child (or parent). The result is a beautiful, completely individual piece of art unique to that child at that time.

Has anyone heared of this type of product and where I could pruchase some. I was also wondering if Liferite would be a similar type of product.

Any idea. All comments and ideas welcome