paul,it depends on the size of the microwave and what you need to do to it and the size of the object being microwaved,when I`m turning thin bowls green,I put it on defrost for 30 secs at a time then leave for a couple of mins to cool,but in this case don`t let it cool,and you`d probaly be ok with 1-2 mins on defrost,(its old and has a twistknob)newer ones you`d have to programme.