have owned and used both diaphragm and piston airless units - still have a piston type unit .....
bloody great for painting canal barges/40ft boxes/rooms - water pistol for paint.
Don't think I'd want to try painting a machine with one ..... would want to be some masking job, not to be blown off by the 1800 PSI jet of paint.
These units will blow a hole in flesh
@Vinpetrol ..... Massive warning notice with them telling you not to **** with them and NEVER get your hand (or any bit of you) in front of the nozzle .... it will inject paint into your tissue and likely lose whatever part of you that gets injected.
The diaphragm units (like that one) are a PITFA to keep functioning well ..... the solvents in the paint and for cleaning them out, knacker the diaphragms .. they go hard and don't work .... and ain't cheap to replace -- and they'm not the best at suction pick up either - set mine up as hopper fed, which improved their performance.
have had a couple of the Wagner units (and skipped the pair of them when I cleared the workshop) ....
the piston type are far superior -- AS LONG AS THEY'RE KEPT CLEAN -- you really need plenty of area to warrant the faff of set up and cleaning (like a canal barge or twistlock - or 20t of steelwork) they are bloody fast though .... can put it on as fast as you can move and a good coat
