I work with MMF a lot, the only down side is it just collapses when taken outside for long.

Is gumpaste a product to add to MMF so that it hardens and does not "melt" or do you use it alone instead of MMF to create decorations that will not collapse because of humidity or other things??

I make my own MMF and it works beautifully, but I need something that will hold up outside for my next project. Thanks.

Do you just mean figures or to cover the cake? Gumpaste will help your MMf to stay harder. I make my own MMf too and if I am molding people or animals etc... I mix it 50/50. It may be better tough if the humidity is really high to use just gumpaste

Gumpaste doesn't taste very nice. It makes your figurines hard and sturdy but it is not easy to eat. I haven't tried the 50/50 mix but when people use it, it is still generally for modelling work.