Air compressor question

[Bird]

Now how about oil lubed vs oil-less? How much is the life expectancy difference of the two?

An employee of a big air-compressor dealer told me to figure about 10 to 1 on the life expectancy. I don't doubt that at all. The oilless are just fine for a homeowner who only wants to air up a car or bicycle tire, or a child's toy, occasionally. When I was a full time RVer, I carried an oilless with a 2 gallon tank in the motorhome, and never had a problem with it, but there was never a need to run it more than a few minutes.

Then when I bought the place in the country, I bought an oilless with a 30 gallon tank. I kept it for about 3 years, but the longest it ever went between rebuilds was 8 months. The first time the reed valves broke, it was still in warranty. Now the good news is that you can completely rebuild one of them in less than an hour and probably spend $15 to $40 for parts, depending on how many parts need replacing.

I always tell people that pretty cowling around the motor and compressor serves two purposes: (1) if you could see what's under there, you wouldn't buy it, and (2) when it blows up, the cowling either stops or slows down the parts it tries to throw at you. But it sure does get noisy when the loose parts start banging around in there.

 

[schmism]

ive run my "shop" with air tools (impact and all) with a HF 1.5 hp pancake for about 4 years now. I use an addtional 20 gal sears tank (the left oververs from when the crapsman died the second time) at full 120psi head pressure then step it down after that with regulator.

its an oil bath type compressor and has worked great at an extreamly high duty cycle at times. what died first? i burnt up the contacts on the crappy pressure switch. So i swapped the pressure switch from the old crapsman onto it. Still running.

 

[SPYDERLK]

Why are oil lubed ones quieter? How do they run in an unheated garage?


I think they are quieter because the oil cushions the parts while it lubes them. I think you can get a decent single stage 2 cylinder oiled compressor for 4-500 $US. These would be in the 3-5HP advertised range. These HP figures are inflated. Check the nameplate specs. You want one that draws AT LEAST 20A @ 110V or 10 A @ 220. This will be an actual 2+HP compressor, but less than 3HP. Buy bigger if you can because you may someday want to use higher duty cycle tools.
As for the cold garage - - motor oils work okay in single stage compressors. Use a light grade Mobile 1 in cold weather. I think you wont be able to use much air in the cold tho, because your tools will ice up.
Larry

 

[jayhaitch]

Bird: 10:1 life expectency? Wow! I'm sold.

Spiderlk: you're right. A 20 gal tank is Can$229, whereas a 5.4 scfm 25 gal Porter Cable compressor is in the $350-500 range here.

Can someone please explain single vs dual stage? I notice dual stage compressors have higher max PSI's, like 175 vs 125-150. Is there any other benefit beside a higher PSI giving more useable air?

 

[Soundguy]

I've painted a few tractors, and run an impact ratchet off a 4galon, 2 hp pancake compresor... I plumbed in a 15 gallon air tank using a couple lines and a 3-way. Takes a bit to initially pump up, and then you ratchet away... By the time you have whatever work done ( change tire.. etc. ).. air is back to put the nuts back on.. etc.

Still.. in the end.. i went ahead and got a 27g 5hp compressor and have been verrrrrrry happy with it..

Soundguy

I have an idea, and would like more experienced opinions.

I have a Porter Cable pancake compressor which works fine for my brad and 15 gauge finish nailers. Worked great with my flooring stapler, but I hope to never do that again! Anyway, for my occaisonal home use, I have an impact wrench and air ratchet. I can't use this compressor with them, runs out of air too fast. So.....

Would it help, and is it feasable to use a portable air tank to increase stored air? I want a portable air tank anyway. Could I install a manifold on the air tank, run an air hose from the compressor to the manifold, and the long hose from the manifold to the tool? If I used a 3 hole manifold, I could also run the air chuck hose and leave the manifold on. Princess Auto has an 11 gal portable air tank available, with a half inch threaded hole for the air valve. I added a 2 hole manifold to my compressor to run the flooring stapler and finish nailer together without having to disconnect/connect each time.

Opinions please?

 

[Tom_Veatch]

...Can someone please explain single vs dual stage? I notice dual stage compressors have higher max PSI's, like 175 vs 125-150. ...

Single stage doesn't require more than a single cylinder - could be more, but isn't required. Air from the cylinder(s) go direct to the storage tank. The air is compressed in a single step or stage.

Dual stage requires at least two cylinders. Compressed air from the first cylinder is routed to the second cylinder where it is compressed to a higher pressure. Air from the second cylinder is routed to the storage tank. The air is compressed in two steps or stages.

 

[Bird]

Can someone please explain single vs dual stage? I notice dual stage compressors have higher max PSI's, like 175 vs 125-150. Is there any other benefit beside a higher PSI giving more useable air?

OK, Tom answered the first part of the question. As for the second part, there are two things to consider: (1) pressure or PSI, and (2) volume or CFM.

You may already be aware of it, but if not . . . nearly all your air tools are rated at 90 psi and that's the maximum that the manufacturers recommend. So if you have a compressor that turns off at 120 psi and comes back on at 90 psi or slightly more, you have all you need if it moves enough volume. Now you can use tools, such as impact and ratchet wrenches, at higher pressure and you'll have more power than the tool is rated for. But of course you'll also put more wear on the tool and possibly break something.

Most tires, even on big rigs, don't need more than 100 psi.

So very few people actually need a bigger, or two stage, compressor, but of course they can sure be handy. I know a couple of air over hydraulic cylinders on the hay baler I used needed 150 psi, but that's the most I've ever actually needed.

 

[CATMAN]

I'll give you my Dad's experience; about 12 years ago he purchased a Craftsman 33 gallon airless,single cylinder, direct drive, vertical compressor. It is a "little to moderately" noiser than his old 2 cylinder oil-type,belt driven compressor.(oil consumption and oil in the air line and wouldn't pump up to pressure). These air compressors live in and enviroment of a 60x75 ft dirt floor machine shed with dust blowing around most of the time. The airless craftsman work fine for ten years, then couldn't pump up to pressure. He took it 60 miles to Sears, only they said it couldn't be repaired. When I can back for harvest time (Iowa farm), I tore into it and it just needed a piston ring/sleeve kit that it shows in the operation manual that one gets with a new compressor. I called the Sears parts order phone number and for a total of $32 and less than an hour, it was just like new again. (very simple design). Heck, the hardest trick was finding a long torx head screwdriver to get the cowling off. We know that the dusty conditions are ruining these compressors, but now that I see how inexpensive and simple the airless style is to repair, I wouldn't hesitate to purchase another one. The 33 gallon style does run the 1/2" impact just fine, but a air diegrinder will run the pressure down some. They are price at $299-$329 USD. Just a little info for ya.

 

[Bird]

Catman, I agree completely. They can be rebuilt pretty quickly, easily, and inexpensively if you have the parts available. Obviously your Dad didn't run his compressor for extended periods of time, so the oilless will last quite awhile. But I was using mine a lot more. In fact the first time it broke I was sandblasting a little trailer prior to painting it. It sounds like your Dad had the same compressor I bought in early '95.

 

[jayhaitch]

Thanks everyone for all your information. I now have a good idea what I should be looking for and why.

Talking to you guys is what I always expected university to be: the university of practical knowledge

Thanks again.