orange peel effect why

when i spray on flat surfaces like a bonnet or boot or roof i get orange peel effect but when i spray say doors wings i dont i am using 2k paint so i dont need laquer afterwords as its all in one also when i spray 2k paint after 3 coats its not very shiney i dont realy want to put to much paint on in a coat incase it runs so i do i go about getting it shiney wivout runs hope you can help thanks

Few reasons are plausible:

A) Not enough paint
B) Spraying to far away
C) Improper mixture
D) To low pressure
E) which stands for etc.

There are several reasons that could be going on. Personally, I hate enamels.

on my airbrush the main reason is that there is not enough thinner..