Air compressor question...

[malconium]

I have a good quality portable air-compressor that has a 15amp motor - the max that can be run on a typical house hold circuit. It is the type with two long and narrow tanks on it. I find it is fine for an air riviter, a small paint spray gun and my brad nailer. It is marginal for a rotary cutoff tool and underpowered for sand blasting.

So here is the question:

Would it help if I added an auxilery air tank or do I really need a larger compressor if I want more capacity?

Thanks,

Malcolm

[bake315]

Well - an auxiliary tank would help, and would be the cheapest way to go for what you're trying to use it for, but I expect you're still looking at having the compressor running an awful lot. I have a vertical 30 gallon Husky with 150 max psi and 5hp oilless compressor. I use it for sandblasting, nailers and the occasional air hammer. It seems to work awfully hard, even with that much capacity - the little motor is noisy and seems ill-suited for anything too serious.

I'd try to find a larger compressor - something 2-cylinder. I'd also look at adding 220 service where you'll be using it. I think you'll be a lot happier with it. Like the sigline of another member says, "suck it up, spend the bucks, do it right the first time". I wish I had, in retrospect.

[juel]

I run everything I need for construction work off my 2 1/2 HP Porter Cable air compressor with no problems. You don't need a 220 compressor unless you are running a paint shop or commercial operation. You can get these compact compressors at Lowe's or Sam's Wholesale. I think you will be satisfied with the operation and capacity of this unit. A reminder, you need to drain your compressor air tank occasionally for it to continue to work as it's supposed to. It may have a condensation build up that hampers the operation. Bob

[zamboni]

It really depends on what you are wan't to do with it. If you only need to sandblast the frame of say, one Airstream, rent or borrow one for the project. If you occasionally do trim carpentry work, I would think the one you have would be fine.

You need to know the volume and pressure of air required by the tool(s) in order to decide the size or capacity of the air compressor. Any air compressor only has the capacity to pump a certain amount of air per minute. If the tool you are using will use more air than the capacity of the air storage tank and pump can supply, you will have to stop using your tool until the compressor can "catch up".

[59toaster]

CFM is what you want. Stuff like sand blasters are huge hogs of air. There was a recent lawsuit about Air compressor mis labeling. http://aircompressorsettlement.com/
A lot of the compressor you could buy in the $400 range at home stores like HD and Lowes were named in that suit as being over rated. Read over that so you know what to look for.

If you need something to run a sand blaster you need a compressor that will provide over 9CFM at 90psi at the very least. The more CFM at 90psi the better performance with air hog items.

[74Argosy24MH]

If you add another tank it will help until the pressure drops in the tanks, then you will be operating of the output of the compressor again; you are going to work the compressor a lot longer refilling the tanks. Sandblasters and tools with turbine motors (grinders, drills, your rotary tool) use more air than a construction compressor can deliver. If you get a big compressor you should also get larger hoses and fittings. The 1/4" hose sold for the smaller compressors is not really big enough for higher air flow, 3/8" would really help.

I agree with 59toaster about a lot of compressors being over rated. Also look at the motors, figure amp draw for the claimed hp output and it can't happen.

John

[TomW]

Originally Posted by malconium

Would it help if I added an auxilery air tank or do I really need a larger compressor if I want more capacity?

That would work fine as long as you are doing occasional work with "air-hog" tools like sandblasters & jitterbugs.

Another thing to keep in mind is the compressor's duty cycle, i.e. how long the compressor can run before needing to rest. I believe most single-stage, home store air compressors are rated at a 50% duty cycle. I do not recall the exact minute interval, but let's say its 5 minutes. A 50% duty cycle means the compressor needs to rest 5 minutes after running for 5 minutes.

So while your auxillary tank idea may fit your needs, you will more than likely exceed the compressor's duty cycle rating working with air-hog tools. For occaisional work, no big deal (within reason). If you have big plans, it would best to investigate a bigger air compressor.

Tom