I’ve been hand building medium to large prices lately but haven’t been successful in firing at all…

Cups are fine but plates or anything bigger than 20cm (hand builder)come out with cracks.
Even from bisque firing….

What could course this?

I dry my pieces until bone dry for about 2 weeks in plastic bag and finish drying in the kiln 50c for 5hrs.
Then bisque fire.

My schedule at the moment for bisque is 60c to 600c then 200c to 1010c. I think it’s rather slow and careful?

I was wondering if anyone use special kiln schedule for hand built pieces??

I’m struggling to find out course of this problem..