Posted: 2/3/2005 12:55:36 PM EDT
|
looking at a new air compressor, sears has them on sale for 425 for one that runs at 175 psi which is good for the type of stuff i do, but looking at it, it is an oilless compressor.... is this good or bad? i have always had the ones where you needed to do periodic changes to the oil to lubricate the pump, i know these have been on the market for a while and have heard nothing bad about them, but what says the arfcom oracle? the other alternative is on that has an oil lubricated compressor, and runs at 130 psi |
| Unless you are running some serious equipment an air compressor that runs 175psi would be very bad for most air tools. They may run stronger for a short time but the seals will fail in most air tools if you run them much over 125psi. I would look at the cfm ratings instead. Most compressors do have regulators to lower the psi, but having the high psi isn't generally needed. We also need to know what you are going to be running with this compressor. An air nailer will only need a small 1.5hp compressor, where as a sander could require as much as a 5hp to keep up. |
|
theRedGoat has a few of those for sale. He is selling them for $380. Might be worth your while to send him an IM. Click here to send him an IM for the link... |
|
CFM ratings are what you want to look at. Don’t be sucked in by the PSI, or HP wars. Air tools are rated by their CFM usage. A 5 HP comp. rated at an honest 7.5 CFM will out perform a 7 HP comp. rated at 5 CFM. Take an honest look at just what you will use it for and get a unit with about 1.5 times the capacity needed. |
| If you find one with a lower CFM rating, but a larger storage tank for a better price, you might take a good long look at it. Air tools are not considered constand demand tools. What this means, is they are used for a short duration. Unlike something like an air motor, which can run constantly. |
|
I've been researching this too. My understanding is that oil-free is good for painting since there's little chance of contaminating your paint with oil. The downside is lifespan. I was planning on installing a water/oil trap in the airline to address the oil-in-the-air issue. D |
|
Actually depends on what you're planning on operating off of the air compressor , the higher the cfm it'll handle the better it is , especially if you do any type of sanding , spray painting /autobody repair - jobs that require a lot of air tool usage.. I prefer a compressor that requires oil , that's what I own & have been doing autobody work for years with the same compressor : a Sanborn unit To controll your air pressure , Install a regulator on the air output |
|
Screw "Oil Less" compressors. They are overgrown diaphrapgm compressors that have nothing for CFM flow above 40psi. You want a good single or dual stage piston compressor, 20 gallon+ tank, and filters in the line for oil (if using to spray), or oilers in the line for tools (if using for wrenches, chisels, etc.) A good compressor is $400+ for the most basic "all around needs of a 'standard shop'" |
|
Some of the very best. Stay away from the oilless...noisy and nowhere as long lasting. www.thomaspumps.com/ |
Get the largest tank you can afford / have room for. It'll help with the longevity of motor by reducing frequent cycling. And pay attention to the CFM ratings, if you are going to use a high volume tool like an air sander. |
Look for one that is at least 6CFM @90psi a 3CFM@90psi (oil-less/diaphragm) would leave the motor running continually, overheating it and greatly shortening the life of the compressor. A big tank helps much so the motor doesn't cycle so much (5 gallon min) The tank will hold the pressure around 130psi, and then regulate it out at 10-130psi with a knob. So if you are only running at 40psi, the CFM is much greater (just a bit less than double for the pressure), but still doesn't make up for a diaphragm compressor vs a piston compressor. i.e. 6CFM@90psi would put out about 10 cfm at 40psi. a 4CFI@90psi would deliver roughly 6CFM at 40psi... |
|
Something like this one. I have one for painting and it ROCKS, plus it is relatively quiet. www.amazon.com/exec/obidos/ASIN/B0000CCXTK/yellowairplan-20/102-9916312-9652166?creative=327641&camp=14573&link_code=as1 |