Air Compressor for garage
- Thread starter ericz
- Start date
- Location
- Terra Firma
In general --
1) Avoid any "oilless" compressor. For example, Sears currently has on sale a 30-gallon, 150 psi, "6 horsepower" (hah!) compressor. But it's oilless, and it's one cylinder, and it puts out very little more CFM than my very old Sears 3 hp compressor. For $80 more Sears has a "real" 2-cylinder, oil-in-sump compressor on a 25-gallon tank that puts out significantly more air.
2) If you have 230 volts in the garage, avoid anything that runs on 115 volts. Even the largest 115 volt compressor isn't up to serious work. Yeah, you can run those air tools, but you'll find yourself having to take frequent breaks to let the compressor catch up to the tool. Unfortunately, I live in a very old house and I have no choice -- I'm stuck with 115 volts in the garage.
1) Avoid any "oilless" compressor. For example, Sears currently has on sale a 30-gallon, 150 psi, "6 horsepower" (hah!) compressor. But it's oilless, and it's one cylinder, and it puts out very little more CFM than my very old Sears 3 hp compressor. For $80 more Sears has a "real" 2-cylinder, oil-in-sump compressor on a 25-gallon tank that puts out significantly more air.
2) If you have 230 volts in the garage, avoid anything that runs on 115 volts. Even the largest 115 volt compressor isn't up to serious work. Yeah, you can run those air tools, but you'll find yourself having to take frequent breaks to let the compressor catch up to the tool. Unfortunately, I live in a very old house and I have no choice -- I'm stuck with 115 volts in the garage.
Matthew Currie
NAXJA Member #760
- Location
- Vermont, land of big clay
Second what Eagle says. Those oilless things are great for lighweight portables to run your power nailer, but for the shop, get something more substantial.
I have a 230volt/2-horse Sears that I bought about 20 years ago on sale. It does just about everything, and the compressor has never quit. The motor broke (a local bricoleur with better machine tools than mine was actually able to fix the sheared armature shaft with a press-on sleeve!), but I can't complain about the service. As far as I know, Sears compressors are still made by De Vilbiss.
I have a 230volt/2-horse Sears that I bought about 20 years ago on sale. It does just about everything, and the compressor has never quit. The motor broke (a local bricoleur with better machine tools than mine was actually able to fix the sheared armature shaft with a press-on sleeve!), but I can't complain about the service. As far as I know, Sears compressors are still made by De Vilbiss.
So based on your experiences, a 2-3 hp compressor will run a tool continuously, such as a grinder?
Eagle mentioned the Sears 25 gal tank - what is the minimum size a tank should be for this type of application?
Thanks for the help, I appreciate the education. I have looked around on-line and in a few stores. There are a lot of configuration options out there.
I don't need a monster, just something to get the job done correctly.
Thanks again
Eagle mentioned the Sears 25 gal tank - what is the minimum size a tank should be for this type of application?
Thanks for the help, I appreciate the education. I have looked around on-line and in a few stores. There are a lot of configuration options out there.
I don't need a monster, just something to get the job done correctly.
Thanks again
PaulJ
NAXJA Forum User
- Location
- Lynnwood, WA
The tank size has nothing to do with what sort of tool you can run continously. The size of the tank will determine how long you can run a tool that consumes more cfm than the compressor can deliver continously. You need to compare the psi and cfm specification of the grinder with the psi and cfm specification for the compressor to determine if you can run it continuously. You'll probably find that you need something on the order of 5 hp or more for continuous duty with a grinder (angle grinder?). For some tools it can be more economical to buy an electric tool.
- Location
- Terra Firma
ericz said:
Nope. My compressor is a 3 HP and when I fire up the die grinder (either one, I have two with differnt wheels), it starts off great and then bogs down real fast. If I'm trying to get any real work done, the compressor runs almost continuously, and I never have full pressure. Mine is a two cylinder compressor.
Check the kind(s) of tool(s) you want to run. They will usually cite a CFM and pressure requirement.For example, here's a 90-degree angle die grinder from Harbor Freight. It's rated 6 CFM at 90 psi. The compressors will usually give you a CFM rating at 40 psi, and another at 90 psi. Most air tools operate at 90 psi. Ideally, you want a compressor that puts out at 90 psi at least as many CFM as the tool with the highest consumption.
I would consider a 25 to 30 gallon tank the minimum. My friend up the road has an 80 gallon vertical, and even that runs out of steam if a couple of us have tools going at once.
A larger tank with higher pressure can help compensate for a lower CFM output. The compressor will have a regulator, so if you have a compressor that puts 150 psi into the tank, the regulator is set for a maximum output of 90 psi to match the tools. That means the tool will run off the residual pressure in the tank until the tank drops below 90 psi. If the compressor only has a maximum of 100 psi, like mine, there isn't that cushion, and the compressor has to run a lot more.
RichP
NAXJA Forum User
- Location
- Effort, Pa
From experience
Match up the specs like everyone says, go shopping, price everything out, look em over and get the next size up. I have never heard anyone say 'Gee, I should have bought the smaller one and saved $30'. Having the larger capacity is better than having one 'right on the mark'.
Match up the specs like everyone says, go shopping, price everything out, look em over and get the next size up. I have never heard anyone say 'Gee, I should have bought the smaller one and saved $30'. Having the larger capacity is better than having one 'right on the mark'.
Anyone have any comments on this one:
http://www.northerntool.com/webapp/...S=on&TEST=Y&productId=158284&categoryId=90143
So far it's what I have picked out. It's in between the good 5hp models and the more common household style.
Lincoln
http://www.northerntool.com/webapp/...S=on&TEST=Y&productId=158284&categoryId=90143
So far it's what I have picked out. It's in between the good 5hp models and the more common household style.
Lincoln
JJ13
NAXJA Forum User
- Location
- Longview Washington
I got the 7hp vertical from Home depot for 399.00... couldn't be happier with it. I don't recall how many gallon it is (60 or 80 I think). It will run a file board fine, and they take more air than just about anything.
- Location
- NC Sandhills
Few things are more aggravating than an A/C that can't keep up with an 'air-hog' tool (like a 1/2" drill, grinder, or serious 1/2" dr impact)
I tend to agree with the 'super size' it philosophy when it comes to A/C, both in tank volume and pump delivery.
Look for terms such as 'cast iron', 'two stage', and '80 gallon.' A 120v A/C is fine for airing up bicycle tires, but very inadequate for much serious work.
I tend to agree with the 'super size' it philosophy when it comes to A/C, both in tank volume and pump delivery.
Look for terms such as 'cast iron', 'two stage', and '80 gallon.' A 120v A/C is fine for airing up bicycle tires, but very inadequate for much serious work.
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