Anyone knowledgeable on air compressors?
#1
I could really use the opinion of someone who is familiar with compressors...

I have  been trying to determine what kind of air compressor I should replace the "old time bomb" with.   I've done quite a bit of reading but have seen a lot of conflicting information 1-stage, 2-stage, dry, oil, rotary, piston, etc. etc.

I am thinking a 30-40 gallon would be the biggest I would want in my cramped little shop (old compressor is a 30 gal.).  It would be nice to have something a little easier on the ears as well even though I do wear hearing protection.

Now, earlier today I got an e-mail from Eastwood introducing a new product, a scroll compressor: Compressor

I tend to take advertising with a huge grain of salt but this thing sounds like a dream come true (except for the price).  My question is basically, could this thing be just as good as they say or are they being misleading?

Thanks guys,

-Ron
11" South Bend lathe - Wells-Index 860C mill - 16" Queen City Shaper
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#2
Hi Ron,

The scroll concept is not new, it's been used in small refrigeration compressors for years. What is new is use of the concept in compressed air applications. I suspect that is due to improved manufacturing capabilities, required to make the larger scroll plates. The pros of a scroll compressor are; few moving parts, no valves or seals to wear and quiet operation. The cons are; limited capacity (volume) and as you mentioned, cost.

Tom



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#3
Why not buy a new pump for your existing compressor? Most of the noise from compressors is intake noise, fit an oil bath air filter and you will be amazed at the difference. New compressors are quieter anyway.
hermetic, proud to be a member of MetalworkingFun since Nov 2012.
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#4
A few years ago I replaced my old noisy compressor pump with the $135 3HP Harbor Freight pump. Same tanks (I have a 20 or 30 gal from old compressor and a guy in the local club gave me his old 35 or 40 gal tank) and motor. You can actually carry on a conversation now without shouting when it runs - and it has more air volume.

Avoid oilless like the plague. I had one. The bearing gets hot and starts working its way out of the frame 'cuze it heats the aluminum frame that holds it in place.

If you go with just replacing the pump, buy oil. They don't all come with oil in 'em.
Logan 200, Clarke 7x12, Index 40H Mill, Boyer-Shultz 612 Surface Grinder, HF 4x6 Bandsaw, ...
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#5
(10-08-2017, 11:57 AM)Vinny Wrote: A few years ago I replaced my old noisy compressor pump with the $135 3HP Harbor Freight pump.  Same tanks (I have a 20 or 30 gal from old compressor and a guy in the local club gave me his old 35 or 40 gal tank) and motor.  You can actually carry on a conversation now without shouting when it runs - and it has more air volume.

Avoid oilless like the plague.  I had one.  The bearing gets hot and starts working its way out of the frame 'cuze it heats the aluminum frame that holds it in place.

If you go with just replacing the pump, buy oil.  They don't all come with oil in 'em.

Smiley-signs009

One can also enclose a compressor and line it with acoustic tile to reduce the noise.  Just made sure you have adequate air flow into & out of the enclosure.  This works best if you have it in a corner and can use and outside air supply.  I've moved compressors outside under cover to 1) gain some room and 2) to reduce shop noise.  If you live somewhere in snow country put it in a small or purpose built shed with a heater in the winter.

Went back & looked to see where you are.  NE is certainly snow country.  In Kearney NE I moved the air compressor outside into an existing small (4 X 6 or so) brick building and put a milk shed heater in it with a thermostat to keep it warm enough in the winter.
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#6
Thanks guys. My situation is probably somewhat unusual so a little more detail may be in order.

I'm a little bit restricted as to what I can do with the installation of a new compressor. The location of my "shop" is in a garage stall at my office building. The added size of an enclosure (an extra 6" - 8") would be difficult to deal with, as it is I have to scoot it around at times to make room. Venting would be another issue all together. Putting an enclosure outside just isn't in the cards for a number of reasons. I already have an hvac unit next to the garage and I'd have to use up a parking stall to put the compressor in and I can't afford to lose a stall (darn government regs). Then there is the possibility of theft and or vandalism. The situation is far from ideal but that is what I have.

Now, I refer to my old compressor as the "time bomb" because it's now about 35-40 years old and the tank has never been drained or checked. (Not all my fault as I've only been using it for a couple of years now.) I expect the tank may not be as structurally sound enough to bet my life on it. I don't want to think what would happen if it decided to let go in such a confined space. Likewise the pump hasn't seen much love over the years.

Add all this to the fact that it only sort of keeps up with my air needs makes a better compressor worth looking in to.

I don't really need a lot of air for general shop use but I do need enough to feed a small sand blaster and paint gun plus I would like to have extra capacity in case my needs increase.

Best regards

-Ron
11" South Bend lathe - Wells-Index 860C mill - 16" Queen City Shaper
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#7
How much would it cost to have the tank hydro tested?  Check with your local welding supply to see if they can do the test, or send it out for testing.
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#8
(10-09-2017, 07:52 PM)Dr Stan Wrote: How much would it cost to have the tank hydro tested?  Check with your local welding supply to see if they can do the test, or send it out for testing.

Good question. I'll have to look in to that.

Thanks,

-Ron
11" South Bend lathe - Wells-Index 860C mill - 16" Queen City Shaper
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#9
Neat technology in the scroll compressor, didn't realize that was what refrigerators used.
Easy to pressure test the tank yourself, fill it with water and use a hand pump to pressurize it. If you have a portable power style jack that would work fine, use oil for the final pressure.
Free advice is worth exactly what you payed for it.
Greg
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