I can ice a cake put the fondant on and before I get finished it will be cracking in spots?

I have had that same issue with satin ice. Many decorators on this site have changed from using it. They  have changed to fonderific, fondx, etc. Pettinice is a great fondant to use also. I would knead the satin ice really good with criscoand then roll on a mat with that has been rubbed with crisco(don,t use a whole lot  and then pick up mat with  rolled out fondant and apply to cake. work fast. hth

I notice, too, that my satin ice cracks sometimes.  I knead it for a while (at least 10 mins) with a little bit of crisco.  I don't coat my work surface with crisco, though... I've found it makes the fondant tacky and harder to work with.  i use straight corn starch on my surfaces.  The times I notice cracking are when I haven't kneaded enough.  Makes for very tired (but very strong!) arms.  

I may try the other brands listed above...  I started using satin ice based on global sugar art's work.

I knead ( about 5 minutes ) my satin ice fondant until it is smooth with a tiny amount of Crisco/shortening on my hands.

Then, I roll it out with a regular silicone rolling pin on a silicone mat.

Next, I flip the mat over my large pvc rolling pin and then I peel the mat back.

I pick up the large rolling pin/pvc pipe with the fondant on it and drape it over the cold cake and it works perfect!

Thank you