This project is all about convenience. My compressor lives in the basement, near my electrical panel, which makes sense as it is a 220 volt compressor, and its big and heavy and hard to move. Dedicated 220 volt outlets are expensive. Air hoses are cheap. So the compressor lives its life in one place.
So the best plan would be to just mount some kind of airline permanently on the outside of my house, with quick connector fitting, to the place where most projects happen. Just power up the compressor in the basement, hook up your airline outside and you are off and working. Sounds great, yes? But his brings up a few issues of its own.
1) Any work you do on a house you own should be well crafted, and designed to last a while and not rust or make a mess.
2) It should be designed with weather in mind, and should not compromise the envelope of your house.
3) If is mounted in a place where you can see it, it should look nice, and not like a large kluged together eyesore
I spent a while trying to figure this project out to make it look good. Every time I would stop at gas station that had a repair garage I would look and see if they had an airline outside and how it was installed. Most of them were horribly done. So the goal was to make this project look nice and get the number of pieces down to a bare minimum. Standard design principle: Less Parts = Better Design. And Make it weather tight. And make it look nice. And get it approved by my wife. This last part is important. This is what I came up with.