> Beware of the ratings found on most compressors today... They are
> wildly overrated, and vary a great deal from manufacturer to manufacturer.
> As a general rule, always buy more compressor than you think you'll ever
> need.. ( well, within limits of course) A basic beadblast
> cabinet will need
> around 3-5 horsepower, which of course rules out 115vac powerlines.
Note that 'horsepower' is even more wildly overrated than cfm. Lots of
compressors seem to be perpetual motion machines, based on their power input
and output. One 'sanity check' I like to apply is checking the nameplate on
the motor for it's rated voltage and current. Multiply those together,
divide by 1000, the result is very close to how much horsepower it actually
puts out. (Yes, I know, a horsepower 'equals' 746 watts. But motors are
not perfectly efficient, nor do they have perfect power factors, and the
nameplate current has to be tad high. 1kVA per true hp is pretty close.)
You can also be suspicious of anything that has a nameplate current over 13
amps or so, and a common household plug on it.
> The "s" stands for standard, i.e..
> controlled temperature + pressure. I doubt it gives the compressor rating
> any more believability, though.
To my mind, giving a rating in scfm at a particular pressure implies at
least a little honesty in lying. I'd be more inclined to believe such a
rating than one given simply as cfm. The line between "creative marketing"
and "false advertising" currently lies somewhere between 'cfm' and 'scfm',
IMO.
> A two stage 3-5 Hp vertical tank compressor (Ingersol, I think) from Home
> Depot is around 8-900 bucks ISTR.
Someone posted not too long ago (perhaps on another list) that HD was no
longer carrying the Ingersol-Rand compressors (which IMO are very high
quality). I checked a few weeks back, and my local store now only has CH
junk and their own 'Husky' house brand.
Randall
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