It is not often that I encounter a game changing blog but this is the exception to the rule. I found David's blog when searching for information on shaping blue foam, his tutorial is truly excellent and has enabled me to use blue foam properly.
Here is the URL:- David Neat
May I just share his excellent work with you
A blow-by-blow instruction of how David created this can be found here
Please note that I have no connection with David except as an admirer of his work.