Announcement

Collapse
No announcement yet.

Air Compressor Persuasion

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Air Compressor Persuasion

    Hey everyone my old man is buying an air compressor for our shop. He wants to get one on wheels with a 50 litre tank, i want to get one with a 110 litre tanks with pallet feel. The compressor needs a 15 amp plug so its not as though we are going to be able to move it anyway. He is not convinced though Can you help me out with some good arguments to get the compressor with the larger tank?

  • #2
    This is my current one which is very good.

    http://i200.photobucket.com/albums/a...mpressor_1.jpg

    Here are its specs:

    http://i200.photobucket.com/albums/a...mpressor_2.jpg

    This will be my next one - gasolene and Honda engine:
    https://www.machineryhouse.com.au/C506

    No power problems, no "hard-wiring in", no need to install 3-phase and is 100% portable, will run my plasma cutter and a small sand-blaster (if I buy one).

    Comment


    • #3
      First it's a serious mistake to think the larger tank makers a larger compressor, it does not! The tank is not sized to increase performance, contrary to popular belief, it is sized ONLY to manage the on/off run cycles based of the pump/motor CFM and projected usage, adding extra tank capacity WILL NOT increase a compressor's performance! Think about it, a tank does not make air it only stores air that's pumped into it and the oft quoted (mis-quoted!) advantage of more "Reserve air" does not make sense. If you double the size of the tank you of course will double the length of time it will operate before running out of air (which usually happens quickly with either size tank on a small compressor) but you must remember you also double the time it takes to recharge the larger tank so the net gain is exactly nothing. The bottom line is that for a given CFM delivery (Cubic feet per minute- converted to however it's rated where you are) the actual run vs wait to catch up time will remain the same during any work period regardless of the size of the tank, small tank=shorter but more frequent cycles and larger tank=longer but fewer cycles, average time remains the same!


      Now after all that here's how to choose the best compressor.

      Basically you need to determine the amount of air you can get by with by looking at the volume of air required to run each tool (in CFM or whatever) then try to match that as closely as possible to the rated delivery volume of the compressor. Remember, it's the volume of air from the PUMP (the CFM rating) that determines the compressor's performance and not what's stored in the tank! If that CFM (volume) rating is low then nothing else matters much, NOTHING! Because a tank cannot put out more air than the pump is delivering to it, a larger tank does NOT equate to a larger compressor!

      Comment


      • #4
        If you are wise, you will find a compressor with an 80 gallon tank and at least 20 CFM. Preferably with a real 5 hp motor. Only issue would be that your 15 amp line won't be enough for one.

        More CFM is better if you want to run a blast cabinet and other large air tools.

        Comment


        • #5
          Originally posted by gnm109
          If you are wise, you will find a compressor with an 80 gallon tank and at least 20 CFM. Preferably with a real 5 hp motor. Only issue would be that your 15 amp line won't be enough for one.

          More CFM is better if you want to run a blast cabinet and other large air tools.

          I agree 20+ CFM @90psi not 40psi. I believe they may run 240V where 15 amps should work.
          "Let me recommend the best medicine in the
          world: a long journey, at a mild season, through a pleasant
          country, in easy stages."
          ~ James Madison

          Comment


          • #6
            Originally posted by flylo
            I agree 20+ CFM @90psi not 40psi. I believe they may run 240V where 15 amps should work.
            Right. I should have added that the 20 SCFM should be at 90 psi. It would be nice to have a 240 VAC motor, too. For some reason, the company that built mine used 120 VAC. It may have to do with marketing and wider sales since not everyone has 240 VAC available.

            Comment


            • #7
              Some very good advice so far.
              But the real question is, what is the intended or perceived use of the air compressor?
              An impact gun to take off the occasional tight set of nuts, inflating a few beach/camping bits, or maybe blowing off a couple of parts?

              Or maybe you intend to sandblast a few pieces of equipment or use an air sander.
              Irregardless it's CF that should be your primary goal.
              Last edited by Willy; 05-18-2012, 12:49 AM.
              Home, down in the valley behind the Red Angus
              Bad Decisions Make Good Stories​

              Location: British Columbia

              Comment


              • #8
                Originally posted by oldtiffie
                ..................
                ...................
                This will be my next one - gasolene and Honda engine:
                https://www.machineryhouse.com.au/C506

                No power problems, no "hard-wiring in", no need to install 3-phase and is 100% portable, will run my plasma cutter and a small sand-blaster (if I buy one).
                Tiffie, while the concept of an "unchained and independent" source of compressed air is a good one. There is a price.

                Think about the luxury of compressed air that is unobtrusive.
                No noise in the background while the power source is chugging away doing nothing but eating fuel, wearing out, and making noise.
                Not having to deal with the option of pull starting the engine whenever you need a puff of air.
                Also keep in mind the extra short cycle increased maintenance you should do, unless of course the unit runs steady and then that will also included more running costs.

                The only time the independence pays for itself is when you don't have the option of a mains powered source.
                Not sure where you may need air. Is it remote?
                Home, down in the valley behind the Red Angus
                Bad Decisions Make Good Stories​

                Location: British Columbia

                Comment


                • #9
                  Picked up 2 last week I;ve never seen. These are 20-25 gallon huge cast iron finned 120V motors true 3HP, 2 stage V twin pumps, twin belt drives. They are basically made for 60 gallon verticle tanks but on smaller roll around tanks. I love them as they go to 135PSI in no time, run slow, quiet, could run all day & nothing gets hot (except the finned copper tube between the heads. I'm sure they're older imports with oil sight glasses) & 2 outlets & 2 handles each as they weigh about 300# each. Tagged Astra on the blue one & Cummins/IHC on the other. Jst odd I've never saw one & buy 3 in a week. These are imports but very good quality & performance. I'll try to get a picture. One has 4 wheels which was a great idea someone had.
                  "Let me recommend the best medicine in the
                  world: a long journey, at a mild season, through a pleasant
                  country, in easy stages."
                  ~ James Madison

                  Comment


                  • #10
                    Look up Harbor Freight - item#56101. Just bought a slightly used one still bolted to the crate bottom for $300. Except mine has the Honda clone engine & it's 2 years old. Divorce sale.Too bad your 1/2 a world away. This would put a smile on your face. Turn the key & 0 to 180 in nothing flat!


                    Originally posted by oldtiffie
                    This is my current one which is very good.

                    http://i200.photobucket.com/albums/a...mpressor_1.jpg

                    Here are its specs:

                    http://i200.photobucket.com/albums/a...mpressor_2.jpg

                    This will be my next one - gasolene and Honda engine:
                    https://www.machineryhouse.com.au/C506

                    No power problems, no "hard-wiring in", no need to install 3-phase and is 100% portable, will run my plasma cutter and a small sand-blaster (if I buy one).
                    "Let me recommend the best medicine in the
                    world: a long journey, at a mild season, through a pleasant
                    country, in easy stages."
                    ~ James Madison

                    Comment


                    • #11
                      Originally posted by Bryce.R
                      Hey everyone my old man is buying an air compressor for our shop. He wants to get one on wheels with a 50 litre tank, i want to get one with a 110 litre tanks with pallet feel. The compressor needs a 15 amp plug so its not as though we are going to be able to move it anyway. He is not convinced though Can you help me out with some good arguments to get the compressor with the larger tank?
                      As others have said, the larger tanks is not going to help much unless it is matched by a larger compression unit.

                      Even though my compressor has wheels, compressors on wheels that are wheeled up to the job are a PITA. They are noisy and they and the lines always get in the way. One of the best things I did in my new shop was to put the compressor outside in a noise suppression chamber and retic the air inside my shop. A full retic is not essential just run some line to a couple of points inside and then use a retractable air hose from there in. After using my setup for 12 months I'd never go back to a compressor inside my shop.

                      Comment


                      • #12
                        Originally posted by BobL
                        As others have said, the larger tanks is not going to help much unless it is matched by a larger compression unit.
                        Sounds good, isn't necessarily so.

                        If the prime need is relatively infrequent use of a fair amount of "surge" CFM, a large tank and small pump MAY be just right.

                        if you had exactly the same compressor pump, and a little "hot dog" tank, you couldn't do that same job...... Not unless you got a much larger pump that could supply the maximum surge CFM.

                        it's all about the "average"...... you can't escape getting enough pump to take care of your average CFM...(or the total daily CFM). But if that use is infrequent use of a lot for a short time, you may well be able to do better with a smaller pump if you have a large tank.

                        The only things are that you need enough tank volume to supply your total air volume for that short time, since the pump isn't going to help much during the usage time, and you need to not require much more air until the tank is full again..
                        1601

                        Keep eye on ball.
                        Hashim Khan

                        Comment


                        • #13
                          I agree - a larger tank is very useful if you needs are "bursty". Same with running at tank at 175psi (and rated for such use!) and having say a 100psi regulator.

                          Comment


                          • #14
                            Originally posted by J Tiers
                            Sounds good, isn't necessarily so.

                            If the prime need is relatively infrequent use of a fair amount of "surge" CFM, a large tank and small pump MAY be just right.
                            Sure I agree in terms of air delivery, but unless the pump is designed to cope with longer pump up times a small pump and large tank is also more likely to wear out the pump and is why it is not wise to just keep adding tanks to a small compressor.

                            On something like a compressor most of the pump wear happens when the machine is at its hottest. So in the case of a small compressor it's probably better if it runs more frequently, for short periods at lower temps, than for long periods infrequently where it has to operate at higher temps for much longer at the end of the pumping cycle.

                            Comment


                            • #15
                              I agree with Bob, while it can certainly be argued that "burst" air supply would indeed be helped by a larger tank this is in most cases going to comprise only a small percentage of the compressor's use, basically only during the odd times where only one tank of air would do the job and the little extra might make the difference. The question is asked all the time "should I get an 80 gallon tank compressor or settle for a 60 gallon" as if the 60 gallon is somehow inferior when the fact is they could not tell the difference. Fellows you can argue all day about tank sizes and the manufacturers of the home shop type compressors love it! They have for years been sticking tiny pumps on top of cheap huge uselessly over-sized tanks knowing full well that a lot of guys, not knowing any better, will run straight to the biggest tank in the store because a big tank just looks, well it looks like a big compressor! This "reserve air" only helps in the odd instance where the compressor is needed for only one run cycle then any time that is gained by the extra tank capacity is lost to the proportionally longer recharge time. I am not saying a big tank is a bad idea just that on a properly designed compressor the tank will be chosen by the designers to balance the run/recharge cycles and adding more tank capacity is in most cases not only useless but in some cases can be counterproductive.


                              In the case of the usual 80 vs 60 argument think of it like this, if the compressor is already running out of air at an annoying rate with a 60 gallon tank than just how long would it take to run out of air if it had only a 20 gallon tank? Obviously it would out in an extremely short time (but would also recharge in a very short time!) but those few extra seconds is all the extra time the 80 gallon tank would add to the 60 gallon's run time but the kicker is that THEN even that is lost to the longer recharge time! Of course if it's not running out of air with the 60 gallon tank then there's no problem in the first place.


                              The bottom line is waaaaay too much emphasis is placed on the size of the storage tank and far too often people look at these tanks and overlook what really matters-THE CFM RATING!!!! An 18 CFM rated compressor with a 60 gallon tank (or even a 40 for that matter) will easily outwork a 16 CFM compressor with an 80 gallon tank but that bigger tank will outsell the smaller one two to one because of the myths and misunderstandings. The fact is the size of the tank (within reason of course) simply does not matter much and matters little at all from a performance standpoint so choose that compressor based on CFM and quality in the price range you can afford and don't worry about the tank!

                              A BIG TANK DOES NOT MAKE A BIG COMPRESSOR!!!
                              Last edited by radkins; 05-18-2012, 11:49 AM.

                              Comment

                              Working...
                              X