I made this compressed air system because I had wanted piped air in the workshop for ages and spray painting my rusting VW van was the impetus.
There were three main elements as I saw it:
1. Conditioning the air, so that it was water and oil free (this is not standard on cheap DIY compressors and even some expensive air compressors).
2.Creating the pipework from a bunch of scrap metal pipes I was given, so that the air compressor(s) could be out of the workshop where the noise wouldn't be so annoying.
3. Ensuring enough airflow to use pro grade paint spraying guns. (This is a lot of CFM at a reasonable pressure).
And here is a video of the whole van painting saga using the new compressed air system.