School me on portable air compressors

[ryan]

I'm moving from an apt to a house, but the house doesn't have a garage. I'll have a decent sized shed for storing tools, etc. I've started looking at portable air compressors, but I'm really not familiar with them.

What do I need to know?

What brands are better than others?

Is tank capacity the #1 consideration, or should I be more focused on duty cycle?

 

[JFortner5]

How big do you want and what kind of tools are you going to use?

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[ryan]

Air tools mostly, might end up needing it inside every now and then as well for a nailer or something

Size isnt a consideration as long as it's portable. I'm comfortable getting a 20-30 gallon tank if it's worth it

 

[Doofy]

For a super handy and easily toteable small compressor I like the small oil-less compressors with small tanks that are used with pneumatic nailers and such. To small for high air volume tools but great for light duty uses.

 

[wizkid00104]

What you need to look at is SCFM of the air tool vs. the compressor.

I have this compressor: http://www.sears.com/33-gallon-quiet-vertical-air-compressor-165psi/p-00916572000P

SCFM Delivery:
SCFM Delivery At 40 psi: 6.8
SCFM Delivery At 90 psi: 5.1

Impacts run at 90 or more so I can run a gun like this without a problem. http://www.northerntool.com/shop/tools/product_200342894_200342894

This gun uses an average of 4.8 SCFM. In an ideal world, if the compressor can put out more SCFM than the tool uses, you can use the tool non-stop. When you go over what the compressor can actually produce, you then begin to wait to build up pressure to run the tools.

 

[JFortner5]

That's the reason I asked which tools because some make a big difference. When I first started looking at compressors I wanted the craftsman 33 gallon. Then I thought about their 20 gal.

I ended up going with am oiled Husky 8 gal from home depot. I really just wanted to use an impact and it does that just fine. Impacts do use a lot of air, but you don't use it constantly. Even with 8 gallons I can take off two wheels before the compressor cycles. Because it's only 8 gallons though it only takes about 30 seconds to get back to 125 psi.

I would not try to use a rotary tool, or sander, or anything that uses a constant supply of air. Even the 33 gallon sears one won't do it. You need a serious compressor for those tools, like 60 gallons and 10scfm or more.

With that said I'm happy with mine, I just wanted it to air up tires and stuff, light use of an impact, and an air nailer. It does all of those great for me. It's not for everyone but I can easily move it around, it takes oil which is a plus to me, and it was only like $130.


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[JFortner5]

Oh yeah and to add to what the guy above said; if the compressor exceeds the rating of the tool you won't run out of air, but unless you have a compressor with a 100% duty cycle it will burn up pretty quick.

The oil less ones have no lubrication, just a piston with a Teflon ring. The oiled ones have a more auto style piston with metal rings. Most all under $400 are direct drive compressors where the motor and pump are one piece. They are all loud regardless of oiled or oil free.

The quiet(er) ones are belt driven, separate motor and pump, and typically are in the $400+ range. Of course then they aren't as portable or even stationary.

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[ryan]

Thanks - all good advice.

Mostly I'll be looking to run air tools - impact, ratchet, cutoff. Not going to be sanding much, but maybe a smaller grinder than my angle grinder.

Any downside, other than portability, to going with the largest possible tank?

 

[RangerSVT]

No downside to a bigger tank other than what you stated. You can connect multiple smaller tanks if you have a smaller compressor, portable storage tank, etc. Grinders/cutoffs pull a lot of volume as well, as stated, check the cfm. A bigger storage tank will help with a smaller compressor, but once air is depleted it'll take longer to fill. How long you run the cutoff would determine what size compressor I would get (the actual compressor, not the tank size)...

SVT

 

[ryan]

any particular brands to avoid? I'm skeptical of the HD/lowes house brands, but not for any real good reason

 

[RangerSVT]

I'd look for the one that has the better warranty for the price, then choose the biggest cfm you can afford...

SVT