Air compressor choices

[WagonCrazy]

I've been working from an 8 gallon tank - 2 hp 4cfm compressor for years, and since I've been involved in restoration/fabbing...have realized this thing is good for about 2 minutes of tool time followed by 6 minutes of wait time.

This lack of cfm's and volume was (again) brought to light this weekend with a great find on Craigslist of a freestanding media blasting cabinet that I picked up. Time to start cleaning up all the aluminum C4 components as I continue the Nomad project.

Researching on the Internet for days now and am resolved not to be tempted by 300 to 400 dollar units that are less than 60 gallons, and less than 10 cfm output. This blaster needs cfms and tank volume or I'll never get anything done!

My budgets about 750 tops. Id like to get one with wheels for portability. I can wire up a 240 volt plug in my garage if needed. 115 v would sure keep it versatile though.

What do you guys recommend? What should I avoid? What's working for you?

[Run-em]

Go, big, bigger, biggest....never can have too much air. You will find things to run on air and for reasons you never imagined. And the proper use of power tools will allow you to keep working on hobbies for far longer during your life. Arthritis has reared its' ugly head for me & I know I couldn't attempt many of the things I do without air.

[chevynut]

The tank size really has nothing to do with much of anything. Once you start blasting and the compressor kicks in, all that matters is CFM. I would get a 60 gallon compressor with as much CFM as possible...no need for an 80 gallon tank. Shoot for 20 CFM+. Also, get a 2-stage compressor. I'm not sure you can get what you need for your $750 budget.

[Bakins]

I got a 2 stage Quincy with a 60 gallon tank from northern tool. Was $1300 or so.

[WagonCrazy]

$750 does seem a bit low for a high cfm 2 stage 60 gallon unit. More like $1K to $1300 by the time I get it home (delivered or picked up at a freight terminal)

This one's a hard one to swallow because it's such a substantial purchase. Its like buying a 1/2 ton truck, then towing your heavy arse toyhauler all over the place, wondering why you evetually burned up the tranny and it has no power anymore. Shoulda bought the big deisel puller...But i'm stuck with mediocrity for air if I don't go for broke at this juncture...

Where's that money tree I know I planted a while ago? Dang, every dollar has been plucked from it.

Saw some "Puma" compressors online that have 3 cylinders and are 2 stage units. 17cfms on the small end and 22+ on the larger ones. About $1200 to $1500 by the time I get it here...

[WagonCrazy]

And the other frustrating thing about looking at these online is they don't all show the decibal specs. Some on various forums complain about them being very loud, and others compliment the quietness...

Many of the listings i look at don't post that spec. Frustrating also.

[567chevys]

Hey Wagoncrazy

Look for a used one
There are good ones out there , just have to check them out before you buy just make sure it's not 3 Phase motor unless you have that kind of power

[Bakins]

And the other frustrating thing about looking at these online is they don't all show the decibal specs. Some on various forums complain about them being very loud, and others compliment the quietness...


My Quincy is loud, but it's in my garage. I'm going to do a "baffle wall" - in my testing that quieted it down a bunch. Basically a wall with some sound insulation between it and the main part of garage. Have to make sure I maintain proper ventilation, etc. I've also looked at some of the intake mufflers, but haven't bought one.

[Rick_L]

I find that my 2 stage compressor is a bit quieter than than the single stage it replaced. And it has about 60% more airflow.

You will not find a 120V unit that has enough power to fill your needs.

As a minimum, if you can afford it, buy a 11-13 cfm single stage, usually comes with a 60 gallon tank. Better yet, 16-18 cfm two stage.

There are lots of choices out there for both of those basic specs.

[chevynut]

If you put your compressor on pads, instead of on the concrete floor, it should quiet it a lot. Mine is going into the new enclosed closet under the stairway in my new shop.

[WagonCrazy]

For $660 delivered, I can get this 2 cylinder, single stage Puma 3hp 60 gal 220v single phase, 12cfm at 90psi 580

For $1110 delivered, I can get this 3 cylinder, single stage Puma 5ph 60 gal 220V single phase, 18 cfm at 90psi 581

For $975 delivered, I can get this 3 cylinder, single stage Magna Force 3hp 80 gal 240V single phase, 14 cfm at 90psi 582

What I reaaaaaaallllly want is a dual stage 3 cylinder single phase 240v one with about a 60 gallon tank. Those are close to $2K delivered.

I am looking for them used for sure, on Craigslist all over the place, but they are few and far between (somewhat in the greater SoCal area) and when the good ones come up, they want a few hundred less than new. Why take a chance on someone elses used equipment. Especially compressors...I'd bet 90% of the reason why people are selling them is because they are lame, putting out low air, worn out, tripping breakers, etc.

Dang. Lotta bucks for these.

Why wouldn't I just be better off to buy 3 $400 dollar 7cfm compressors, and hook em all up in tandem? Sell 'em one at a time when I dont' need em.

But in fact, I do need the cfms to do blasting and stuff like that.

Aaargh...

[chevynut]

Paul, I bought an Ingersoll-Rand compressor for $1200....240V single phase 5 HP 60 gallon two-stage and 15 CFM @ 175 PSI. I can tell you that my blasting cabinet and even my die grinder taxes it. When I'm using my blasting cabinet, I can run the pressure down but usually don't have to wait for it to come back very much. Here's what I bought:

http://www.aircompressorsdirect.com/Ingersoll-Rand-2340L5.230-1-Air-Compressor/p705.html

If I had it to do over again, I would buy even a higher CFM one. But it's hard to find them over 15-17 CFM.

I think I got mine here...check them out. Free shipping.

http://www.aircompressorsdirect.com/

[chevynut]

Also, when comparing CFM ratings, make sure you're comparing them at the same pressure.

It looks like the Puma 18 CFM one you posted is a good deal if the specs check out...but remember that's 18CFM at 90 PSI. The IR compressor is 15 CFM at 175 PSI. NO WAY will a 3HP compressor do what you need.

[chevynut]

I think this is what I should have bought for a few more bucks....

http://www.ebay.com/itm/SCHULZ-AIR-COMPRESSOR-7-5HP-80-GALLON-TANK-30CFM-175-PSI-/230700118062?pt=BI_Air_Compressors&hash=item35b6cc702e

http://www.ebay.com/itm/NEW-INGERSOLL-RAND-TYPE-30-RECIPROCATING-AIR-COMPRESSOR-7-5-HP-3-PHASE-80-GALLON-/130723956194?pt=LH_DefaultDomain_0&hash=item1e6fc145e2

[Bakins]

This is the one I have: http://www.northerntool.com/shop/tools/product_200350475_200350475
I like it a lot, but my use has been fairly light. I have a local northern tool, so I picked it up. A local-ish shop also services them (on-site) if needed - that helped make my decision.
Not affiliated in anyway, just a happy customer :) If I did more work, I'd go bigger like Laszlo said. I probably won't paint with mine as I found out my neighbor has a paint booth.

[chevynut]

Actually my experience is that painting takes a lot less air than blasting or using some air tools. My compressor doesn't run much when I'm shooting primer, even using HVLP.

[Bakins]

Actually my experience is that painting takes a lot less air than blasting or using some air tools. My compressor doesn't run much when I'm shooting primer, even using HVLP.

I was talking about moisture, etc.

In my playing with tools last couple of weeks (finally got some time) I've been happy with my compressor.

[Rick_L]

The bigger and more efficient the compressor, and the less it runs, reduces moisture in the lines.

[Bakins]

FWIW - using the compressor more now in the hot and humid Georgia summer. I am getting some moisture. With 95% humidity, that's not really surprising. My moisture separator is doing okay, but I probably need to do something better - a better filter and/or more pipe with another water trap.

[warren57]

I pretty much agree with everyone that has answered, with just a few comments. I build my own units (retired pipefitter and mechanical contractor) Definitely a two stage. Try to get Cast iron in lieu of aluminum and years down the road you rebuild it just as you do a car. As for tank, I disagree with some of the others, it has a lot to do with your system. When you compress 175# into a large tank and start using it at 100 lbs or less, It will run your tools longer before the compressor has to start. It also allows for longer run time when the compressor cycles and running is much easier than starting/stopping. In heavy industrial use they still use compressors that run continuous and have cylinder unloaders to control pressure. No different than a light bulb, turning them on uses more energy and continual on/off burns them out. Motor windings are no different. Also a larger tank gives the compressed air better cooling to separate the water at the tank (dryer, cooler air) About the largest HP 220V single phase motor made is 7 HP, although 5 HP is much more common. Get the largest CFM and highest pressure you can with one of these motors.

[chevynut]

As for tank, I disagree with some of the others, it has a lot to do with your system. When you compress 175# into a large tank and start using it at 100 lbs or less, It will run your tools longer before the compressor has to start. It also allows for longer run time when the compressor cycles and running is much easier than starting/stopping.

That's true until the compressor starts running...at that point if you're using more air than the compressor can pump, it will run continuously. It's hard to get a reasonably priced compressor that won't run continuously when sandblasting, or even using a die grinder. Mine is an IR and it runs a lot. So the tank size is pretty much irrelevant when you're using a lot of CFM. But I agree that at 175PSI and a large tank you store more air. I'm not sure it's worth the consideration though.



Also a larger tank gives the compressed air better cooling to separate the water at the tank (dryer, cooler air) About the largest HP 220V single phase motor made is 7 HP, although 5 HP is much more common. Get the largest CFM and highest pressure you can with one of these motors.

True on the cooling, but if it runs a lot even a larger tank is going to get hot. The air heats up when compressed, and it is transferred to the tank. It doesn't have to be very hot for the air to retain moisture.

[WagonCrazy]

Well guys, I'm' gonna say here that I havent yet pulled the trigger to buy one and been using my 2 horse 20 gallon compressor for the time being. I've had a small amount to blast, so it takes time to fill up and the pressure is so low...but I got it to work long enough to clean up the C4 aluminum rear end parts before I reassembled them. But I definately need a bigger compressor to keep this up.

Everythings a grand in this hobby...

A grand for a custom made FI tank with internal pump-regulator
A grand for coilovers all around
A grand for all the stainless parts to plumb in the fuel and brake lines
A grand for all the stainless to do the custom exhaust system
A grand for this and for that...

To sink $1500 into a compressor that gets used now but not alot is making me go crazy. Funds are somewhat limited after all with 2 kids in college and one more on the way.

Seen alot of used ones on craigslist locally, but not sure about buying someone elses junk on this one...

So I'm glad I posted this and heard all your feedback. Just ain't gonna be able to spend the $ on it yet. :(

[chevynut]

Isn't this hobby GRAND? :)

[warren57]

Now I'm laughing, I never looked at it that way, but yes it really is a $ GRAND $ hobby!!!
But it sure is enjoyable, even on a low budget...:rolleyes:

[WagonCrazy]

I think I just figured out my personalized license plates:
57GRAND

How's that sound?

[Bakins]

I think I just figured out my personalized license plates:
57GRAND


May need to swap the first two digits ;)

[NickP]

That's true until the compressor starts running...at that point if you're using more air than the compressor can pump, it will run continuously. It's hard to get a reasonably priced compressor that won't run continuously when sandblasting, or even using a die grinder. Mine is an IR and it runs a lot. So the tank size is pretty much irrelevant when you're using a lot of CFM. But I agree that at 175PSI and a large tank you store more air. I'm not sure it's worth the consideration though.




True on the cooling, but if it runs a lot even a larger tank is going to get hot. The air heats up when compressed, and it is transferred to the tank. It doesn't have to be very hot for the air to retain moisture.

I run a dryer to eliminate the condensation to my air tools. My tank has an auto dump to keep it to a minimum. With filters and proper line layout - no water. BTW, the compressoe is also a 30 CFM - quiet and will catch up quickly.

[chevynut]

Nick, a 30CFM compressor should have no problem with just about anything. What brand and model is it?

I don't get moisture in my hoses either since I put a second tank on the opposite corner of my shop that the air dumps into before distribution lines. The air cools down between the compressor and the other tank, and the moisture drops into the other tank. It works well, and I don't need a separate refrigerated dryer.

[Bakins]

I don't get moisture in my hoses either since I put a second tank on the opposite corner of my shop that the air dumps into before distribution lines.

I need to do something like that. I did my plumbing like this: http://www.tptools.com/pl/Images,metal_pipe_kits_L,74,2035_Modular-Metal-Piping-Kits.html and bought the water separator/filter combo from them, but still get some moisture -- particularly if the compressor runs a good bit. I guess because it stays hot if it kicks on and off a lot.

[WagonCrazy]

May need to swap the first two digits ;)

Yeah! No kidding. More like 99 grand by the time I get done!