"Charlie Bress" wrote in message
...
:I have a pressure washer. It's a little electric Karcher. The
price was
: right. It was given to me by a contractor who was doing some
repairs
: required by the building inspection. He had a gas driven washer
and asked if
: I wanted the little electric job. As I said the price was
right.
:
: Now where I live the house are all vinyl sided and subject to
the weather of
: south Florida. Needless to sat cleaning the house is an
expected chore. The
: first couple of years here I had the house professionally
cleaned. I just
: used the little cleaner for the driveway, car etc. I was not
happy with the
: job the pros did. They are in a hurry to finish and get on to
the next job.
:
: So I started out with the Karcher. It is rated at about 1500
psi. It doesn't
: have an extension wand so I find in a couple of spots I need to
use a ladder
: (to reach the gable ends, for instance) It takes me a lot
longer, but I am
: now retired and have more time than money so that is not a bad
thing.
:
: Here's the question. My washer puts out a stream at 1500 psi. I
can get up
: close to the siding, say 10 inches or less.
: The pro washer puts out a stream at, let's say, 3000 psi but
this spray
: starts out up to 18 inches away from the siding.
:
: Since in both cases the pressure starts to fall off immediately
after
: leaving the nozzle, what is the relative pressure at the siding
in each
: case.
: /
:
: This is not a trivial problem. My Google search only found lots
of
: motherhood statements about what cleans better, but in the real
world there
: are differences in applying the stream to the work surface.
:
: Anybody out there "know" what the answer is or have a source of
information
: about it?
:
:
: Charlie
:
:
I can't help you much, but I can tell you that if I used my 2,600
psi sprayer on pencil setting at ten inches from the siding, it'd
punch a hole it it real quick or at least create a tear,
depending on the temperature of the air!
I do use it to clean the house, but at a fan setting, not the
pencil. It sounds like you might not be aware of the nuances of
the sprayers.

To figure the force you'd have to know the nozzle dimensions,
actual pressure developed, air mix, devliery pressure, hose
length/dia, water rate, etc etc etc. In ohter words, I don't
think there are any easy answers to this question but it would be
nice to have some ballpark numbers, not because I think they'd be
very useful.
If you want to do a gross ballpark, decrease the pressure by
the square of the distance from the washer nozzle and you'll be
approximately approximate g.
I'm also surprised you're able to use even a 1500 psi sprayer
on a ladder; mine has enough punch behind it to actually push me
around the driveway in my wheelchair when I do the driveway. A
boy and his toys, I know g.

HTH,

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