I used truck air hose to connect the black pipe to the compressor.  Since the air brake compressor had the same 175# pressure, I had no problems.  My hoses were looking bad on the truck, so I bought the pretty coiled colored lines to replace the black hoses that kinked so easy.  Used the lines previously used on the truck to connect the compressor to the black pipe, and again to connect the black pipe to the hose reel.

At a factory where I used to work, (Anaconda American Brass--now called Anamet) we made a special copper connector that was convoluted copper inside with a wire braid outside that was for connecting compressors in air conditioner units.  This would work great in this application, but I would imagine now the air compressor cost would be less than the cost of a copper connector.