Hamish Hubbard (and Ode) wrote:
> Air - Clearly a 5hp compressor is needed to run air tools. By my
> calculations this is too much for the standard household wiring to
> supply which is 2400W (5hp roughly equals 3500W?).
Horsepower ratings for compressors are all over the place,
especially between countries and over decades.
For instance, my 5hp Campbell Hausfield compressor only has
slightly better air output than a two decade old compressor
a friend has that is labelled a 1hp.
(disclaimer for the electrical section, I don't know
if New Zealand household current is 110 or 220 and at
what typical current, around here typical house wiring
is 110V/15A)
As for the electrical issues, I beleive the current rating
for horsepower is the current consumed at stall, which is
the highest moment of drain for an electric motor. Since you
can't stall a compressor, you don't blow fuses.
The 5hp one I have is the maximum you can use on a
15A circuit. You have to use it on it's own circuit
more or less, I pop a breaker if the wife starts the
central vacuuming system while the compressor is on.
Ignore horsepower, go for cfm @ 90psi. For reference,
my 5hp is listed at 5.8cfm@90psi. That's about as much
as you can get in a portable 110V model, at least
around here. For the same money however, if 220V
stationary is ok, you can get an upright that will
do 11.6cfm@90psi.
Look at the tools you are going to use, and get enough
psi for them. For automotive, you'll probably want at
least what I have, and more if you don't mind 220V. (I
have multiple locations so I wanted 110V)
> Welding - lots of people like MIG. My main objection is that if you
> do introduce welding distortion there is not a lot that can be done
> about it
You can hammer it back.
However, if you introduce distortion with a MIG you would
have to be magic to go without using gas. MIG makes an
instant weld, with gas you need to heat the area up by holding
the torch on the metal. This gives the heat a lot of time
to spread as well, so the potential warpage goes much
farther.
> and also that it leaves a big seam that needs to be ground
> off. Comments? Most of my panel work will be panel replacement with
> very little patching, hence I want a spot welder. I want gas for the
> cutting and heating abilities as well as the ability to weld
> "seamlessly".
Take a welding course where you can practice with a lot
of techniques and learn what you can and can't do.
Frankly, MIG welds are extremely pretty and clean when
done well. Perhaps your experience is with "flux core" MIG
welding, which isn't really MIG welding but closer to
arc welding? It is a bit messy, like arc welding.
Flipping through my welding manuals where "pro" gas welds
and "pro" MIG welds are done, I can't honestly agree that
the gas welds are anything close to seamless.
> I have practiced and am aware of the difficulties of
> heat distortion but still prefer this method over MIG. I would get
> a TIG setup if I could afford it.
TIG is very nice, but you may find it hard to do as
an occasional hobbyist. It requires a fair bit of practice
and coordination, which is a hard thing to stay in top
form when you are only using it periodically.
Don't get me wrong, I'd LOVE to have a TIG in my shop. But
I'd still use the MIG for body work. I think most body shops
agree, many have all kinds of welding equipment and still
use the MIG for panelwork.
--
Trevor Boicey, Ottawa, Canada.
tboicey@brit.ca, http://www.brit.ca/~tboicey/
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