Wonder how well a shower pump would do as a power wash / parts washer substitute.
Used ones seem to be cheap enough (£10-£20) in the usual Facebook, GumTree, local free ad papers or even E-Bay sources. Proper power wash lances can also be found cheaply, or even free, as the inexpensive power washers are less than durable so the pump dies before the accessories do. Or possibly those cheap hose pressure intensifier nozzles from the "cheap import tat" online suppliers actually do work. I have a design for one that reliable sources say really does go well, reportedly lethal on the end of a power washer (!), so its not impossible.
Like all these make do, mod and mend deals it does depend on what stuff you have in your "will come in handy box(es)". Anything beyond fairly minimal buying and careful choice from inexpensive new offerings comes out cheaper and works well enough. As I know to my cost having frequently spent much time effort and creativity to save about thruppence three farthing over just buying something.
I sold my industrial standard Kew pressure washer and got a "£50" jobbie from LiDL. The Kew was significantly better but the LiDL cheapy works well enough and is far less cumbersome. Only place it seriously looses out is the biannual heavy patio cleaning session. No substitute for super pressure and lots of flow when shifting the slippery green stuff.
However when it comes to sandblasting the inexpensive kit really has to be considered unsatisfactory and makes even the simplest job hard work. Blasting needs plenty of air and a decent extractor system on the cabinet to get the job done in reasonable time. I have a pro Guyson cabinet with the proper extractor so I can see what I'm doing. My Hydrovane 502 makes 10 cu ft (nominal) of air and barely keeps up with the demands of the smallest air nozzle. Small nozzle makes for slow work. One day I'll upgrade the workshop electrics, drag the (freebie) Hydrovane 504 out of storage and fit a bigger air nozzle. 20 cfm is exponentially better than 10 for this sort of thing.
At least the Hydrovane is quiet. Just a gentle buzz from the other side of a chipboard partition wall. The racket from a modern, high speed, DIY rated reciprocator on similar duties would be pure torture. Even with my crappy hearing. The hefty cast iron Atlas Copco Vee twin running at 1,000 rpm that preceded the Hydrovane was way quieter than anything modern but still not exactly a comfortable noise level.