Painters use two types of sprayers -- those that use air and those that don't. The latter type is called an airless sprayer. Both require hoses, but for different reasons. The hose on an air sprayer supplies air from a compressor, which mixes with the paint to form a spray of atomised paint particles. The hose on an airless sprayer, on the other hand, supplies paint. A hydraulic pump forces it into the hose and out the tip of the gun. The methods for connecting these two types of hoses are different.
Separate a swivel adaptor by pulling the outside sleeve away from the point of connection. This will free the connection so you can pull the two sections of the adaptor apart.
Screw the female end of the swivel adaptor onto the end of an air hose fitted with a 1/4-inch male pipe-thread adaptor. Wrap plumbing tape around the threads on the hose first. Tighten on the swivel adaptor with a wrench. Screw the male end of the swivel adaptor into the threaded hole in the handle of an air spray gun in the same way.
Connect the gun to the hose by pulling back on the outer sleeve of the female half you attached to the hose, while you insert the male half attached to the gun. Release the sleeve when the two halves are fully seated.
Connect another adaptor to the other end of the hose and to an air compressor in the same way. This will allow you to quickly remove the hose when you need to move or store the compressor.
Connect an airless spray gun to the hydraulic pump that powers it with a high-pressure hose.
Screw the 1/4-inch female pipe-thread connector on the end of the hose to the male connector on the end of the gun. Tighten it with a wrench.
Screw the other end of the hose to the hydraulic pump in the same way.
Because the hose for an airless sprayer contains paint rather than air, you don't usually need to reinforce the connections with plumbing tape. You might need to, though, if you are spraying thin material like waterproofing sealer.
Before you use an airless hose, check it for small punctures, and use another hose if you find any. Paint can be forced through these holes with enough force to penetrate skin.