"Bill" wrote in message
...
In message , Hugo Nebula
writes
Reading car forums, the overwhelming opinion is that a pressure washer
is needed to wash one's car properly. So I went and bought a cheap
Halfords one, complete with snow foam attachment. The results were
disappointing to say the least.

I know it's not a mega powerful one, but I was amazed at how low the
pressure was out of the nozzle. I was certain my hose gave a more
powerful flow, so I did an experiment and timed how long it took to
fill a bucket, and therefore what the flow rate is from my tap. It
amounts to 1,000 litres per hour, nearly three times the flow rate of
the PW. Some of the best pressure washers only appear to give half of
that.

Am I missing something here? Is pressure a function of the flow rate,
and if so, what's the point of a pressure washer if it gives less than
mains pressure?


They, as the name suggests, provide extra pressure and not flow rate, so I
would expect an open hose to provide a higher flow rate, otherwise they
would be sucking water out of your mains.

I use a middle of the road Karcher and it is marvellous, fetches paving
slabs and concrete back to a nice crisp finish and clears most of the dirt
off the car.

Those are mainly what I use mine for, plus with not-so-great drainage in my
back garden, I can clean it all without flooding the garden because it uses
less water than a hose. The patio looks like new at the moment, I don't
think anything else would bring it up that clean.

I'm assuming the best way to compare tap versus jetwasher is the bar
measurement rather than flow rate. I think my washer is about 120bar, that's
way more than a tap. You can stop a tap running with your thumb over it, you
ain't stopping a jet from these machines.