Looking to purchase compressor

Discussion in 'Irrigation' started by grassmanak, Nov 26, 2006.

  1. grassmanak

    grassmanak LawnSite Senior Member
    Messages: 792

    Im looking at purchasing an air compressor. I originally was just going to spend 500.00 on an eletric one for the garage, but i do a handful of blowouts and i was thinking maybe it would be nice to have a gas unit. Any body have any recomendations. Strictly Residential properties. Anything special to look for when buying a unit.
  2. Wet_Boots

    Wet_Boots LawnSite Fanatic
    Messages: 50,884

    You might check with what Grainger has. See if you can compare the build of their own house brands, like Speedaire, Dayton, Westward, etc. with Ingersoll Rand. Starting from scratch, with 20/20 hindsight, I'd have spent the bucks (now close to $2000) for an IR on a 30 gallon tank. But you can start smaller, with a 20 gallon portable, with a single-stage air pump, and it can handle your standard residentials, one zone at a time, with a wait between zones, maybe.

    It might make more sense to look for a used compressor on eBay. No doubt the money for a new IR truck-mount compressor would go a long way towards a decent used tow-behind.
  3. grassmanak

    grassmanak LawnSite Senior Member
    Messages: 792

    is gas definetly the way to go, or would it be good to purchase a big electric and a generator. Im not really sure, i normally just sub these out, but its go to the point, where i could pay for a machine in one season on my own. Im looking for something i could either mount on my trailer or load into the back of my truck when i need it. Im sure a complete unit on its own trailer would be quite spendy.
  4. Wet_Boots

    Wet_Boots LawnSite Fanatic
    Messages: 50,884

    Does anyone use the combination of an electric compressor and a generator? I expect there are limits to what size of motor can be reliably started from a generator. Bolting a portable compressor to a truck bed might put a strain on the pieces of metal that support the tank. Not so much where the wheels are, but the other end, where I've twice had breakage. The first time cost me the tank itself (original non-ASME tank)

    Grainger's cheapest might work well for you. I winterized a football field with one like it, back in the early days. (It had a mainline to inflate, and yes, I brought a lunch) ~ I do wonder about the quality of the build, over a very long term, compared to an Ingersoll Rand. From experience, I'd be looking for a solid heavy platform for the components. I have no gripe about the Grainger pump itself, but I know that the motor platform on my replacement tank was made for electric motors, and not gasoline engines, since it has a tendency to crack once every season or so. (They now list a separate replacement tank for engine-driven compressors - too late for me, though, so I get to play with the arc welder)

    If you found a decent used electric compressor, it might be possible to replace the electric motor with a gasoline engine. The usual factor for replacement is 2 - that is, replace a 10HP electric motor with a 20 HP gasoline engine, in order to have the necessary torque to run the pump. If you like to tinker, you might enjoy trying to build your own custom rig, like my current idea of a sled-mounted engine and pump, with a tank on the side.

    MOW PRO LAWN SERVICE LawnSite Bronze Member
    Messages: 1,568

    Try northern tool sometimes you get a good price and free shipping.
  6. Mdirrigation

    Mdirrigation LawnSite Gold Member
    Messages: 3,810

    Dont waste time or money on a electric rig . Go to the auction and pick up a tow behind . I have bought them as low as 600 dollars that last me 3 years . My 125 cfm diesel was 1100 dollars with 775 hours on it
  7. Wet_Boots

    Wet_Boots LawnSite Fanatic
    Messages: 50,884

    If you do have the room for a tow-behind, that's obviously the first choice. I'll always keep a truckmount around, so I can get to some of the trailer-unfriendly locations I service. Every part of the country won't have the same access to good older compressors, so it's one of those 'your mileage may vary' situations. I would budget higher for something you could count on a decade of service from. The one advantage of going with a well-known truckmount, is the ability to keep the thing in service, even when you have to replace belts or engines or pumps. (Avoid something you need to trot out the arc welder for, though)

    My old Grainger has become something of a 'great grandaddy's axe' with it working with it's fifth engine, second tank, second pump, etc.
  8. grassmanak

    grassmanak LawnSite Senior Member
    Messages: 792

    i dont want a tow behind rig, id like to just mount a compressor on my trailer, in my truck, finish mowing my property or whatever, and then blow out the lines, i also dont have space for another trailer. What is the minumum CFM i should buy and at what PSI, i was looking at a 50 gallon electric and a compressor, probably around a grand, would this be a bad idea. If not what should i look for in a gas unit as far as tank size and motor horsepower.
  9. Ground Master

    Ground Master LawnSite Senior Member
    Messages: 505

    $1000. might get you a 8hp gas unit putting out 16 to 20 cfm, but you'll soon realize its a little weak for blowing out systems. Although it can do it, just slowly.

    You'd be happier with a 13 to 15hp rig capable of 25 to 30 cfm. New will set you back $2000.

    I've seen some portable 25 hp rotary screws that put out 90 cfm. These will set you back $6000. You could mount these units on a trailer.

    As far as $ per cfm goes the cheapest route is a used tow behind unit.

    Your idea of an electric unit powered by a gas compressor takes up alot of space and will cost alot to get even a minimum of 20 cfm.
  10. Wet_Boots

    Wet_Boots LawnSite Fanatic
    Messages: 50,884

    The compressor pictured below, is older than you are, and is identical to the one I did a football field with. Probably delivered less than 10 cfm as it was configured. They don't make them that small anymore. With an 11 or 12 gallon tank, the use of a hundred-odd feet of 3/4" hose on a cart made a real difference in the 'air charge' you could build up.

    How handy are you? Mechanically inclined? Good at welding? None of the above? That would figure into any idea of buying any old equipment, or the components to configure a homemade truckmount. One thousand is an awkward amount to spend on a new truck-mount, since the going rate for a brand-new solid rig on a 30 gallon stationary tank is closer to two thousand.

    This one is a configuration they didn't have, back when. Bigger tank, stronger platform, but not as strong as on a stationary built for the larger engines and two-stage pumps. Their current entry-level portable could be a problem as a truck-mount, since just bolting it to a trailer or truck bed would strain the tank support strap. (construct a wooden cradle to support the tank, to take some of the load off) Another misgiving is the engine platform, which looks a lot like the one that often cracks on my replacement tank.

    There are reciprocating pumps that are much more heavily constructed than anything in the Grainger house brands. Ingersoll Rand T-series, for a start. Quincy, for sure. There are others. eBay has them listed all the time, but for something used, that won't be demonstrated as running, your mileage will vary, of course.


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