MikeP
|
| posted on 29/1/06 at 04:08 PM |
|
|
Upgrading my air compressor...
... looks like an expensive proposition. I've got one of those 5ish HP / 25gal ones, about 10 or 12 years old.
Do I sell it and spring for a big ones at 2x the cost? Or is it possible to buy one of those cheaper ones and use it as a "helper" for my
current unit?
I'm thinking I could use both by hooking them to a common manifold. If I did that, would the shared manifold be better at regulated pressure or
tank pressure w/ a separate regulator?
Seems like the regulated pressure would be more convenient - I could split them up easily when I want to move one around/outside the garage - I could
use a quick disconnect. OTOH it'd be easier to regulate a single output from high pressure.
Has anyone here played around with something like this?
I bought myself a carbide rotary file for xmas - what a time saver! Of course now my compressor can't keep up with the die grinder  .
|
|
|
|
|
JoelP
|
| posted on 29/1/06 at 05:23 PM |
|
|
i find it hard to believe that a 5hp compressor wont keep up with a die grinder. If it really is, theres no hope for me! Id start with a 200l second
hand air tank, and see how it goes. Failing that, rock bottom price seems to be about £50 per 1.5hp. Obviously thats a cheap tool of probably limited
life.
|
|
|
MikeP
|
| posted on 29/1/06 at 11:53 PM |
|
|
That rating is back from before there was that legal action to get the compressor manufacturers to specify their effective hp... It's carefully
*not* marked on the machine or the manual, so I could be mis-remembering. The specs are given as 8.2/6.1 cfm at 40/90psi, a 115 @15amp motor, single
stage pump.
Fine print on the die grinder: "rating assumes a 25% duty cycle, use 4 times that rating for continuous operation". No problem for my
impact wrench or ratchet, but my grinder uses a LOT of air and pretty much continuously.
It'd take a long time to fill up that second cylinder, waiting for the current 25gal to fill seems long enough! A clone of my current
compressor is < $500, a smaller version around $250. The one I really want is around $1000 (well, the one I really, really want is closer to $2000
 ).
|
|
|
cossey
|
| posted on 30/1/06 at 08:46 AM |
|
|
well that motor is 1725w which is 2.3hp.
have you considered getting a new motor and a 2 stage pump and fitting it onto your existing tank. that way it should be a lot cheaper but still boost
how much air it can shift. something like a 3-4hp 220v motor (assuming you use the same system as usa for electricity) could power something around
12cfm. that should easily be able to keep up with the die grinder and would reduce the wait to fill up the tank at the start.
|
|
|
DarrenW
|
| posted on 30/1/06 at 09:06 AM |
|
|
5HP is a huge motor for a small compressor and will run at around 35A which is a lot for a domestic installation over a long period. Starting current
will be approx 45 - 50A.
115V x 15A = 1725W
1HP is very roughly 775W.
the motor might pull 15A on start up which means it will run at approx 10 or 11A. Or it could pull 15A running when the tank is almost full.
1725W is approx 2HP at best.
I cant help thinking that running 2 small compreesors into the same line wont give you much more than a single one. You would probs need to run them
into a third larger tank. i ported a cylinder head using a die grinder off a 50l 1.5Hp compressor. I had to let the tank catch up quite a lot and most
of the time the grinder was a bit slow but it worked and i managed OK. Just had to be a bit more patient.
|
|
|
NS Dev
|
| posted on 30/1/06 at 09:25 AM |
|
|
I had all this!
I bought the big compressor anyway, but that's for the pressure blaster!
Air die grinders are horrible things, they eat air, get flipping freezing cold and the exhaust air blows grit everywhere.
I have an electric die grinder, which was not cheap but SOOOO much nicey.
Retro RWD is the way forward...........automotive fabrication, car restoration, sheetmetal work, engine conversion
retro car restoration and tuning
|
|
|
cossey
|
| posted on 30/1/06 at 09:50 AM |
|
|
is that just a supersized dremel?
|
|
|
Peteff
|
| posted on 30/1/06 at 09:51 AM |
|
|
I have one of the Aldi electric die grinders which was cheap. I don't use the air one any more as the compressor uses about 5 times as much
electricity keeping up with it and the electric one works just as well and as Dan says, is more comfortable to use.
yours, Pete
I went into the RSPCA office the other day. It was so small you could hardly swing a cat in there.
|
|
|
NS Dev
|
| posted on 30/1/06 at 01:13 PM |
|
|
quote:
Originally posted by cossey
is that just a supersized dremel?
Sort of but MUCH more powerful!!!!
It's what the pros use for porting, so it's what I bought!....
linky
Retro RWD is the way forward...........automotive fabrication, car restoration, sheetmetal work, engine conversion
retro car restoration and tuning
|
|
|
MikeP
|
| posted on 30/1/06 at 01:53 PM |
|
|
Wow NS, those are nice, but expensive! I know what you mean about the air grinder, freezing cold, double that here in the winter, no fun at all.
You've far more patience than me Darren - I can hardly wait for the compressor to fill for 5 minutes of grinding!
I've been watching the 2 stages - princess auto over here puts them on sale once in a while. Still pretty pricy, but then I could upgrade to a
larger tank later if I needed and keep my smaller compressor for portability (such as it is). Yes, we run at 220v too - of course I'd need to
rewire either way, even 2x 115V units need to be on separate breakers, that's a wash.
What I'm hearing is "no, don't bother" on the idea of a second equal size compressor? Looks like I'm going to need to
learn patience for the next little while then.
Thanks all!
|
|
|
JoelP
|
| posted on 30/1/06 at 06:37 PM |
|
|
i see no harm in using two seperate compressors working together. Unless it would need a rewire - im not familiar with canadian wiring, but its a
rather pathetic circuit that cant provide 3.5kws! I suppose the 115V is the first kick in the nads...
|
|
|
DEAN C.
|
| posted on 30/1/06 at 07:00 PM |
|
|
Mike,
just go and buy a proper sized job as big as you can afford and sell the old one.
I've done quite a lot with pneumatics and compressors,and its the cfm you need.
The only way to get real volume is to buy a good sized job with the bigger pump and large tank to match.
I have a 3hp 14cfm,250ltr and that usually keeps up,although air grinders and die grinders still take some keeping up with.
Over here 3hp is as big as is practical in the home workshop,and anything bigger is usually on commercial 3 phase electrics.
Dean
Once I've finished a project why do I start another?
|
|
|
JoelP
|
| posted on 30/1/06 at 08:02 PM |
|
|
my 1.5hp one isnt too bad with the die grinder. Every time the pressure drops to 4 bar, i stop and pick the crap out of the teeth on the whirrly
thing. Im guessing about a 10% duty cycle though! 
|
|
|
