The goal is to have the finished paint as flat as possible, without any sort of ripple or distortion in it. To get there, every step of the way matters.
- Getting the body filler work straight. There are a lot of techniques and things to cover on how, but the foundation needs to be correct first.
- Primer Texture. Every time product is sprayed, it has texture in it. This texture needs to be cut out of it completely. This is a very important step, that gets mildly over looked. Sure, primer gets blocked out, and it looks completely smooth and nice...but everything is hiding. The key is to use as sharp of sand paper and possible, with as hard of a block as possible.
- There isn't very much of a difference between completely flat and almost flat. To get to completely flat, everything matters. This is why using 80 or 100 grit matters, and why using the correct sanding blocks matters, because there is no way to cut that very last bit of texture out with a durablock that is just a hard chunk of foam. Yes, you can get pretty good results, but they aren't the best. **Polyester primer has to be sanded completely flat, everywhere, with no finer than 100 grit. 120 will sand it, but it won't be flat enough.
- Clear Texture. This is the same exact theory as getting the primer flat, except that the end result is dependent on how flat the primer is. Clear must be sanded completely flat with 600 grit (800 works too) and a hard block. The hard block is even more important with clear coat.
- Again! The clear will never be completely flat if the primer isn't completely flat. This is important!!
- All this is the entire reason I believe so strongly in True Blox. They work, and if you are trying to achieve exceptionally great results, nothing else works. It's not a sales pitch, it's reality.