How to repair cracked dash?

[warwgn]

Keep in mind that when I did mine I found the spray foam was a waste of time. I stated the was just an experiment to see how it would hold up but in the future I will redo it again and just use felt and fiberglass resin. The main thing I want to know is how the flex seal holds up in the sun and cold and humidity and time before I invest time and effort in doing it right. It has already cracked a little from flexing it when I put it in but did not get worse yet, but we will see what the summer heat and sun do to it.