Working time on bondo filler, glass, and hair is only about 5 minutes. It takes 20 minutes to fully cure.
I ussually start sanding after 15 mins....
The putty glaze is not necessary, but it helps. You will have all these tiny little divets when you finish with the glass. most of those will fill with bodyfiller. However some tiny ones will be left as well as some of the deeper sanding lines. It just means you need to use more filler primer and more wetsanding.
