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Topic Review (Newest First)
10-13-2011 07:55 AM
utk03analyst I'm no expert, I'm a novice painter as well, I purchased a used compressor with a 22 gallon tank and a 5hp motor, it put's out over 8 cfm at 60 psi and a little over 6 cfm at 90 psi. It had no trouble keeping up with my HVLP and it actually didn't cycle that much.

The only advice I have is make sure your compressor puts out enough cfm to run your gun. If I didn't get the deal I got on my compressor there's a 15 gallon Dewalt compressor at HomeD that puts out 5cfm at 90 psi.
10-13-2011 07:08 AM
S10xGN
Quote:
Originally Posted by 66GMC
Did I miss something here?
Where has the OP even hinted that he wasn't happy with oldred's (or anyone elses' for that matter) advice?

I sort of thought that was the entire concept here at HR.com.
Nobody (as far as I know) gets paid to provide information (factual or otherwise) or to express their opinions or beliefs.

So give opinions and advice based on your experience, and it's up to the reader to decide the validity of what is said.
A "Take it or leave it" scenario.

IMO, It's OK to have varying viewpoints ... that is one of the best ways to actually learn something.
The OP has never posted back with any concerns. The only recommendation (?) Mr. "red" has alluded to concerns tank size or lack of it. Poster #2 brings a good point, but most guns these days are HVLP, so I recommended a SCFM rating based on that. Still have not seen any other recommendations on anything other than "don't be concerned about tank size", if one considers that a "recommendation" for buying a compressor. You're right, everyone has an opinion. So far I've only seen one (other than mine) in this entire thread.

To the OP - another thing to consider, whenever you buy connectors, step up to the hi-flow coupler sets. These will really perk up any air tools and give better control on spray guns. Of course, others may not see it this way...

Russ
10-12-2011 12:45 PM
66GMC
Quote:
Originally Posted by S10xGN
Enough with the bashing already, just give the man the recommendation he asked for!
Russ
Did I miss something here?
Where has the OP even hinted that he wasn't happy with oldred's (or anyone elses' for that matter) advice?

I sort of thought that was the entire concept here at HR.com.
Nobody (as far as I know) gets paid to provide information (factual or otherwise) or to express their opinions or beliefs.

So give opinions and advice based on your experience, and it's up to the reader to decide the validity of what is said.
A "Take it or leave it" scenario.

IMO, It's OK to have varying viewpoints ... that is one of the best ways to actually learn something.
10-12-2011 10:09 AM
oldred
Quote:
Originally Posted by S10xGN
Enough with the bashing already, just give the man the recommendation he asked for!

I think I did a couple of times, buy based on CFM, duty cycle and quality vs what the budget allows.

I was not bashing, I was simply trying to explain why the bigger tank does not help but it is not something that can be explained in one sentence. Obviously you are annoyed by my suggestion to not worry about air storage (within reason of course) but the guy is about to spend money on a piece of equipment and probably can not afford to make a mistake. I was in the business for years and dealt with the "bigger tank is better" myth when dealing with customers who needed an adequate air supply for their service trucks. If I did it wrong and they were not satisfied they came back on me so I learned long ago what works and what don't.
10-12-2011 09:54 AM
S10xGN
Quote:
Originally Posted by oldred
Honestly that is a serious mistake, a marginally performing compressor is the WORST case for a bigger tank! The (mis)logic behind a larger tank is in thinking it will extend run time but that is not thinking beyond the first recharge cycle at which point ALL extra time gained will then be lost to the proportionally longer recharge time so nothing is gained. Usually a compressor with a larger tank will be mated to a higher CFM compressor but the problem is that is not always true, selecting a compressor by the size of the tank can easily cause a person to pass up better performance for a uselessly over-sized tank. As I pointed out earlier the difference in run time between an 80 gallon tank and a 60 is going to be mere seconds anyway then the tank has to recharge and even that extra time is lost waiting on the longer recharge time for the larger tank to refill (with all else being equal), if the compressor keeps up then no waiting will be required but again in that case the tank makes zero difference in performance. With equal CFM ratings a 60 gallon tank will average the same run vs recharge time as an 80 gallon tank, heck if the CFM is the same even a 40 gallon tank would keep up just as well but the cycle rate might be annoying. For that matter a 40 gallon compressor with 13 CFM would OUTPERFORM a 12 CFM compressor with an 80 gallon tank! It's easy to find compressors with 60 gallon tanks that will outperform some 80 gallon models and that's why telling someone to look for a big tank is terribly misguided advice. CFM is what makes a compressor keep up and a few gallons of extra tank storage only changes the cycle rate and does not help at all to keep up with air hungry tools, over a given work period the run time vs the time spent waiting on recharge will be exactly the same between 60 gallons or 80. The larger tank will yield fewer but longer recharge cycles but the average run time will be the same if all else is equal. Select that compressor based on SCFM and overall quality because it is how much CFM the pump is putting into the tank that matters not how much the tank can hold!



I am not saying to avoid big tanks, just don't buy based on the thinking that it's going to make a better performing compressor because it won't. The manufacturer will size the tank according to the PUMP/Motor and expected usage demand so that the run and recharge times will be reasonably balanced, NOT to increase performance. On some cheaper models a large tank is used to create the appearance of being a large compressor but they may have small under powered pumps with low CFM ratings that mean they actually are in fact small compressors, some of those things would actually be better off with a smaller tank. The bottom line is for most home shops a compressor of adequate size will most likely be either a 60 gallon tank or an 80 gallon and either is just fine but that should depend on the CFM, in any case NEVER, EVER pass up higher CFM to get a bigger tank- NEVER! Buy based on CFM and duty cycle because that's what makes a compressor keep up and don't worry about a few tank gallons one way or the other!
Enough with the bashing already, just give the man the recommendation he asked for! After all, you ARE the expert here. You've wasted a bunch of time typing and still nothing of substance except your very critical opinion on tank size...


Russ
10-11-2011 09:52 PM
oldred
Quote:
Originally Posted by 66GMC
II'm not suggesting that you run out and buy a 30+ scfm Quincy Refrigerated Screw Compressor for your home hobby shop.


Maybe not but it sure would be nice!
10-11-2011 09:35 PM
66GMC I've learned that buying "barely adequate for my present needs" usually translates to selling it at a loss, and buying what I should have bought in the first place later.



Within reason, of course.

I'm not suggesting that you run out and buy a 30+ scfm Quincy Refrigerated Screw Compressor for your home hobby shop.
10-11-2011 09:24 PM
oldred
Quote:
Originally Posted by S10xGN
My point was - if you're buying a marginal compressor, get one with the largest tank you can. Russ


Honestly that is a serious mistake, a marginally performing compressor is the WORST case for a bigger tank! The (mis)logic behind a larger tank is in thinking it will extend run time but that is not thinking beyond the first recharge cycle at which point ALL extra time gained will then be lost to the proportionally longer recharge time so nothing is gained. Usually a compressor with a larger tank will be mated to a higher CFM compressor but the problem is that is not always true, selecting a compressor by the size of the tank can easily cause a person to pass up better performance for a uselessly over-sized tank. As I pointed out earlier the difference in run time between an 80 gallon tank and a 60 is going to be mere seconds anyway then the tank has to recharge and even that extra time is lost waiting on the longer recharge time for the larger tank to refill (with all else being equal), if the compressor keeps up then no waiting will be required but again in that case the tank makes zero difference in performance. With equal CFM ratings a 60 gallon tank will average the same run vs recharge time as an 80 gallon tank, heck if the CFM is the same even a 40 gallon tank would keep up just as well but the cycle rate might be annoying. For that matter a 40 gallon compressor with 13 CFM would OUTPERFORM a 12 CFM compressor with an 80 gallon tank! It's easy to find compressors with 60 gallon tanks that will outperform some 80 gallon models and that's why telling someone to look for a big tank is terribly misguided advice. CFM is what makes a compressor keep up and a few gallons of extra tank storage only changes the cycle rate and does not help at all to keep up with air hungry tools, over a given work period the run time vs the time spent waiting on recharge will be exactly the same between 60 gallons or 80. The larger tank will yield fewer but longer recharge cycles but the average run time will be the same if all else is equal. Select that compressor based on SCFM and overall quality because it is how much CFM the pump is putting into the tank that matters not how much the tank can hold!



I am not saying to avoid big tanks, just don't buy based on the thinking that it's going to make a better performing compressor because it won't. The manufacturer will size the tank according to the PUMP/Motor and expected usage demand so that the run and recharge times will be reasonably balanced, NOT to increase performance. On some cheaper models a large tank is used to create the appearance of being a large compressor but they may have small under powered pumps with low CFM ratings that mean they actually are in fact small compressors, some of those things would actually be better off with a smaller tank. The bottom line is for most home shops a compressor of adequate size will most likely be either a 60 gallon tank or an 80 gallon and either is just fine but that should depend on the CFM, in any case NEVER, EVER pass up higher CFM to get a bigger tank- NEVER! Buy based on CFM and duty cycle because that's what makes a compressor keep up and don't worry about a few tank gallons one way or the other!
10-11-2011 08:22 PM
S10xGN My point was - if you're buying a marginal compressor, get one with the largest tank you can. In theory, if you had a 10000 gal tank, you could spray all day without it cycling. BTW, all that negativism and no recommendation to the OP?

Russ
10-11-2011 02:47 PM
oldred Once again, the size of the tank is not what's important! There will be exactly no noticeable difference between the performance of a 60 gallon tank and an 80 gallon and the slight differences there are does NOT translate to better performance! This has been covered a couple of dozen times at least and a quick search will bring up tons of info on selecting a compressor but buying one based on the size of the tank is a big mistake. CFM is what matters so base the selection of the compressor on the CFM performance vs the projected CFM requirements. Basically when selecting a compressor the buyer should consider the SCFM rating, duty cycle and overall quality vs the amount of money he can spend, the size of the tank (within reason) simply does not matter- a big tank does NOT MAKE A BIG COMPRESSOR!!!


The difference in run time between a 60 gallon tank and an 80 gallon when using air hungry tools like paint guns is mere seconds and then even that is lost to the proportionally longer recharge time, nothing is gained. Over any given work period the run time vs the recharge times will be exactly the same regardless of the size of the tank so it is and always will be a trade off. Larger tanks are used with higher CFM compressors to balance the run vs recharge times and do NOT increase the performance, that is not and never was their purpose. The problem is that compressor manufacturers are well aware that some people will run straight to the biggest tank in the store because a huge tanks just look big and bad so the cheaper outfits mount small under powered compressors on uselessly over-sized tanks to dupe the buyer into thinking he is getting more compressor than he really is, a tank can not put out more air than the pump puts in! If a 60 gallon tank is running out of air at an annoying rate at a certain rate of usage then just how long would it take to run out if the tank was only 20 gallons? Obviously it would be a short time indeed but that's all the extra run time that would be gained between 80 vs 60 gallons and then even that will be lost to the longer recharge time so NOTHING is gained. Buy CFM and quality and don't worry about the tank, the tank will be sized according to the pump and motor by the manufacturer.
10-11-2011 09:06 AM
S10xGN If you've got room for a big tank, that can become pretty important when using air for long periods (as in painting). I'd buy an 80 gal unit with at least 12 CFM output at 90 PSI. Also buy good line filters. The smaller the compressor, the more it will run and the more it runs, the more moisture that gets in the system...

Russ
10-10-2011 07:25 PM
Max1775 What type of spray gun are you using? HVLP, LVLP? Normally small compressors have a heck of a time keeping up with paint. You need to figure out what CFM you are going to need.
10-10-2011 04:29 PM
39chevy
Compressor Question!

I need a compressor that is the smallest size I can get to withstand spray painting (car). I am only occasional painter so I won't be painting a whole lot? Let me know the CFM's and HP and size of tank! I want the minimum size but will still do the job, thanks, Dana

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