I started with the air tank. It is constructed using 2 inch diameter PVC pipe (schedule 40) with a pair of caps. A hole was drilled and tapped for 10-32 threads to accept a Clippard fitting. An adhesive dot was placed over the hole before painting.
PVC glue was applied to the threaded hole before inserting the Clippart CT4 1/16 hose barb fitting. Be careful with the glue. As you can see it will remove paint.