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Morgan22 01-18-2008 11:32 AM

Compressor Tank Size
 
I'm considering buying this compressor, but they also have the exact same one only it has a smaller tank (30gal) instead of 60 gal.

What would be the differance that I could expect with the smaller tank?
Run less or more often to catch up when I use my air tools?

http://www.aircompressorsdirect.com/...roducts_id=591

Hope the link works, copy and paste if not.

Morgan

AllSteel34 01-18-2008 11:52 AM

I would buy the largest tank you can afford. Especially if you paint. The larger the volume, the less pressure fluctuation you will see. The motor will run cooler and for less time overall.

Chris

oldred 01-18-2008 12:45 PM

That is a lot of money for that compressor, believe it or not Harbor Freight has that exact same Puma compressor for quite a bit less than that.


http://www.harborfreight.com/cpi/cta...emnumber=34887

On that outfit with that CFM rating the 60 gallon tank would probably be the best choice unless you need mobility and then the 30 gal would be the way to go, there would not be as much difference as most people think and it would keep up just as well. The largest tank available is not always the best choice and there are quite a few cheaper lower CFM 80 gallon models that could actually be better off with a 60 gallon due to the long recharge times. With a CFM range (@90 PSI) of about 10 to 16 CFM a 60 gallon tank is about right and 16 on up to about 25 CFM or so an 80 gallon tank would probably be somewhat better but less than 9 CFM really should have something a bit smaller than 60 gal. All of this of course depends a great deal on how much demand you will place on the compressor and in a small or home type shop with low demands then tank size really does not mean a lot, within reasonable sizes anyway.

Morgan22 01-18-2008 01:51 PM

Re: Compressor Tank Size
 
Thanks Guys,

Actually I had seen the one from Harbor and they are out of stock when I called yesterday. I just used the link to show the Model I was thinking of.
I still owe you one Oldred, thanks. :thumbup:

Has anyone had one of these Puma compressors and what did you think of it?
I liked the separate cylinders, I thought they would tend to run cooler.

Morgan

302 Z28 01-18-2008 09:44 PM

Never heard of Puma, probably a Chinese import would be my guess.

Vince

65x2 01-19-2008 06:55 AM

I have an 80 gal 5hp unit from Northern and it runs almost constantly when I use my mud hog to cut filler; I'm about to pipe it into my 60 gal unit that went bad. So I'd definitely say bigger is better. Like stated especially if you plan to paint.

http://www.northerntool.com/webapp/w...1707_200311707
This one looks pretty close and a bit cheaper--- these units looked like nice units as well! Free shipping too!

302 Z28 01-19-2008 07:03 AM

It has been discussed hundreds of times in this and other forums. Tank size has little to nothing to do with how long your compressor will run while using it. That is solely a function of how much air your compressor is capable of moving at a certain pressure (SCFM@?psi). Also what is the duty cycle.

Vince

oldred 01-19-2008 08:49 AM

[QUOTE=65x2]I have an 80 gal 5hp unit from Northern and it runs almost constantly when I use my mud hog to cut filler; I'm about to pipe it into my 60 gal unit that went bad. So I'd definitely say bigger is better. Like stated especially if you plan to paint./QUOTE]


If you are disappointed with that thing now just wait (and you will be doing a LOT of that!) until you are trying to recharge a 140 gal tank! As has been said over and over and over and over, "A BIG TANK DOES NOT MAKE A BIG COMPRESSOR"!!! :nono: Sure you will get a little more run time at first, but a lot less than you may be thinking and then comes the trade off, you will be in for a looooong wait for the compressor to recover when it runs out of air which it will still do. Your problem is the pump is not replacing the air as fast as it is being used and more tank capacity will not help this. Running out of air with a sander when trying to use a tank that big would be a PITA but at least you could take a break while the compressor is recharging (and most likely overheating also due to the prolonged run time) but running out while spraying paint could be a disaster! If you are using a HVLP gun for instance and your pressure runs low you will most likely exceed the flash times while waiting for that thing to recover. Your pump is already too small for the tank you have which is common on these econo compressors and adding even more tank capacity is going to make things worse not better, here's one big reason why- A bigger tank may run a bit longer before running out of air but then it takes a correspondingly longer time to recharge so the run time vs the wait time is the same and you gain nothing! Those long recharge times will cause the pump to get hot and a hot pump/air causes a loss of efficiency which means your pump will produce less air the hotter it gets. By exceeding the duty cycle and allowing the pump to run hot that big tank will actually make your compressor less efficient causing you to have to wait even more than you would with the smaller tank. Bigger is better? Actually what you have is an example of what I mentioned earlier about some 80 gal models that would work better with a 60 gal tank, bigger is NOT better in this case!

AntnyL 01-19-2008 09:13 AM

The advice here is spot on. You need a compressor with a higher cfm rating, not a bigger reservoir. To estimate how much compressor capacity you need, take your thirstiest air tool and multiply its cfm consumption by 2. That'll give you an idea of how much capacity you'll need. If you run that tool continuously, your compressor will run 50% of the time.

Example: My inline sander's rated consumption is about 9 cfm at 90 psi. So I looked for a compressor with a rating of about 18 cfm at 90 psi. The 5 hp 60-gallon Ingersoll Rand model seemed to be a good selection for me, so far so good.

Hope this helps.

Morgan22 01-19-2008 12:01 PM

re: Compressor Tank Size
 
Thanks for all the replies,

I just have one more question, the link for this compressor that 65X2
posted says that this compressor uses Reed Valves, does that make any differance or do they all have something like that?


http://www.northerntool.com/webapp/...11707_200311707


thanks,

Morgan

oldred 01-19-2008 01:55 PM

Most of those single stage pumps use reed valves and there really is nothing uncommon about stainless for the material. 11.2 CFM@90PSI and 3.6 HP, at least they are being honest about the numbers which is a refreshing change! :) IMO the Puma would be the better choice because, IMO anyway, the V type pumps work better and run cooler which means better efficiency = higher CFM per HP. Puma also has built a fairly decent reputation for reliability and even though I have never used one the two that I know of look like they are well built and the owners speak quite highly of them.

65x2 01-20-2008 11:10 AM

First let me apologize for giving incorrect advice!
Secondly, let me say, oldred... wish I would have ran across a post like this before I purchased my compressor. I actually purchased it due to the CFM rating being enough to run my Sata spray guns. Thankfully I don't have enough room in my garage to paint a disassembled car all at once. Nor the amount of stands to hold all the parts ! :D So it works well for me, for painting a couple panels at a time then rolling in the chassis and shooting it.
I will definitely reconsider piping the two together now!

Thanks,
Luke

Kampr 01-20-2008 01:38 PM

The $699.00 price of that compressor is getting close to the price of a cheaper 2 stage. If you're going to spend that much money you might as well add a little and get the 2 stage. You'll be much happier in the long run.

Danny

oldred 01-20-2008 03:56 PM

Quote:

Originally Posted by Kampr
you might as well add a little and get the 2 stage. You'll be much happier in the long run.Danny


....... :thumbup:......

aminga 01-20-2008 04:47 PM

Quote:

Originally Posted by Morgan22
Thanks Guys,

Actually I had seen the one from Harbor and they are out of stock when I called yesterday. I just used the link to show the Model I was thinking of.
I still owe you one Oldred, thanks. :thumbup:

Has anyone had one of these Puma compressors and what did you think of it?
I liked the separate cylinders, I thought they would tend to run cooler.

Morgan

Morgan,

I just hooked up a 7.5 HP PUMA in my garage. No word on durability. But it's a baldor industrial Motor. Cast iron pump (3 cylinder) And it appears to put out what they say 25 CFM) because it will keep up with my sand blaster running with the biggest nozzle in place.

The only downside is that tank pressure gauge wasn't reading right. I just haven't called them to get a replacement.


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