Larger compressor questions

Peter Rideout

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Good Morning Everyone
My apologies for ploughing old ground again, as I'm sure this has been addressed before, but I'm on the road and can't really search threads very well.
I'm hoping for some helpful tips on larger upright type compressors. Brands to look for or avoid? Spraying, sandblasting and air tools would be our eventual uses.
Would a used tank and compressor, without motor be a thing to avoid?
What should we look for?
Any advice would be appreciated, as always.
Peter
 
quincy makes a quality compressor and so des the industrial version of Ingersol Rand.

i have a used unit and its doing me just fine but i dont use as hard as you might on your farm..
 
The main thing is to make sure it can put out high cfm. If you can find a rotary compressor that would be the way to go as they can pump out well over 25cfm without trying. I would be looking for a 60 gallon tank. I like quincy they are exellent.
 
One of the things I am considering when I get a larger compressor is two tanks. I use air intermittently... sometimes just enough to shoot a few nails, other time for major projects (spraying, etc.). And sometimes not at all for weeks at a time. There are a couple considerations...

1. One of my friends kept the pressure on his air tank. Then he had a pipe leak, and found the compressor (in an out-building) had been running flat out for days. I only want to turn the compressor on when I will be using it.

2. I hate the time (and energy) it takes to fill a big tank, if all I am going to do is shoot a few brads.

My solution, which I have never seen implemented, is to have a small tank (3-5 gallons) that is always on-line, but also a big tank (30-60 gallons) that is connected to the distribution system with a valve. If I am going to be using a lot of air, open the valve to the big tank and have the luxury of a large amount of air. If I just need a little, close the valve to the big tank and get full pressure in the little tank very quickly. This idea seems straightforward, but since nobody else has done it, I am worried about it.
 
I disagree with Larry. Assuming there are no leaks, I see no reason why the small tank would have any less pressure than the big tank.

Seems like a workable solution to me, Charlie.


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in your proposed idea i think you will loose presure and there for get unseated nails soon..

I don't see where I would lose pressure. If I had a 50 gallon tank and a 5 gallon tank, and the valve were open (both tanks were in the system) how would that be any different than if I had a compressor with a 55 gallon tank? The instant I opened the valve to the big tank, the compressor would have to kick in to fill the bigger tank. Just for discussion, assume it took 3 minutes to fill the big tank - during the 3 minutes while the tank was filling, the pressure would be down, but once the tank was filled, it seems like I am good to go, and would have as much pressure as any 55 gallon system.
 
I can't see why that idea wouldn't work Charlie, but like you, I'd like to hear from someone who's done it.
I saw an ad here for a 60 gal tank and compressor, but no motor, for $150. I think it would need 5hp, but what would the other specs be, rpm etc? I seem to recall from some of the Bill Pentz discussions that compressor motors were a breed apart. Haven't seen it, nor do I know it's age or condition. Might check it out next week.
Getting a little tired of lugging the so-called "portable" hotdog compressor around. I wonder how much 1/4 inch line you could run off that for light jobs like nailing, inflating, dust blowing etc?
Thanks
Peter
 
...I saw an ad here for a 60 gal tank and compressor, but no motor, for $150. I think it would need 5hp, but what would the other specs be, rpm etc? ...

I know many, maybe most compressors have motors running at the standard 3450 rpm, and others (like mine) running at 1740 rpm. A pump should work with either speed motor, but the slower motor on a given pump will compress less air in a given time than the faster motor will. On the other hand, the slower motor will put less stress on the pump, which will add to its longevity and let it run more quietly. In the case of my compressor, it's got a 5 hp motor at 1740 rpm turning a pump that's designed to run on a 7.5 hp 3450 rpm motor. The net result is that my compressor runs more quietly and with less wear on the pump (by being slower), but still puts out 19+ cfm since it's an oversized pump. Chances are, the pump you're looking at is designed to run with a 3450 rpm motor. It'd be quieter with a slower motor, but it might not put out as much air as you'll need.

All this talk of motor RPM is somewhat moot at this point though, since the pulley size plays a big part in how fast the pump is running. If you go see it, make a note of the size of the pulley on the pump, and see if the owner know what size the motor pulley is supposed to be.
 
Rather than running lots of 1/4 inch hose, I recommend 1/2 inch copper tubing. Don't be tempted to substitute PVC - one of my friends did, and when it burst a year later, it blew a big hunk of Sheetrock off the wall, and they never found all the shards of PVC shrapnel - glad I wasn't in the area. Then plug a 25 foot or whatever flex hose to the nearest outlet on the copper line.
 
well, vaughn your probably right in this case as it is described now.. but i was going on the fact that the compressor was to be off and run just on the little storage tank.. that was where i was thinking that yu would loose pressure like a tire looses air fast at first then slows down as thew volume decreases..
 
The only problem with buying a compressor with out a motor is you dont know if the tank is soild or if the compressor it self has any life left in it. A 5hp compressor motor can cost you $400 plus.
 
The only problem with buying a compressor with out a motor is you dont know if the tank is soild or if the compressor it self has any life left in it. A 5hp compressor motor can cost you $400 plus.

That's right Al. Might not be much of a bargain. I might run and have a look at it next week if I have time, but it's over an hour away and not on any regular route I normally take.
The other thing is, I don't have an urgent need for it, as opposed to proper dust collection in the shop and about $10,000 of work on the buildings this summer (and a good 8' mower, and machinery storage, and more permanent fencing and, and....).
But, we will have use for a big compressor sooner rather than later and this discussion has been very helpful.
 
Good Morning Everyone

Would a used tank and compressor, without motor be a thing to avoid?
What should we look for?
Any advice would be appreciated, as always.
Peter

A lot of tanks are dated with a useful safe life. Once that date is past, you 'should' change out your tank. Just something to keep an eye on. I know people who have been using the same tank for decades though.

A compressor motor is just like your automobile motor, they wear out eventually and need rebuilt. They have pistons, valves etc that need to be checked out. So, kinda like checking out a new car or other engine, look for the same things, compression, noise, etc. if you go used. Nothing wrong with used.

You can always change the flywheels to alter the speed if your compressor motor is diff from what the compressor is supposed to run at. You will want a continuous duty motor.

I used to work in a shop rebuilding compressors. I've worked on and rebuilt the Ingersoll Rand compressors, very good (but for some reason I always had to wait for parts. Seems they built a part once it was ordered and didn't keep a very large stock inventory on hand.) I've also worked on and rebuilt Quincy compressors. If I were to buy one, used or new, it would be a Quincy. They go from small to commercial screw type. They will last you your life time.

Either of these two brands will do you well. You can buy tanks separately too and put your own compressor together with motor, compressor and tank from 3 diff places with out too much trouble. Just all depends on your budget and time frame.:thumb:
 
One of the things I am considering when I get a larger compressor is two tanks. I use air intermittently... sometimes just enough to shoot a few nails, other time for major projects (spraying, etc.). And sometimes not at all for weeks at a time. There are a couple considerations...

1. One of my friends kept the pressure on his air tank. Then he had a pipe leak, and found the compressor (in an out-building) had been running flat out for days. I only want to turn the compressor on when I will be using it.

2. I hate the time (and energy) it takes to fill a big tank, if all I am going to do is shoot a few brads.

My solution, which I have never seen implemented, is to have a small tank (3-5 gallons) that is always on-line, but also a big tank (30-60 gallons) that is connected to the distribution system with a valve. If I am going to be using a lot of air, open the valve to the big tank and have the luxury of a large amount of air. If I just need a little, close the valve to the big tank and get full pressure in the little tank very quickly. This idea seems straightforward, but since nobody else has done it, I am worried about it.

This would be easy to do and very doable. The one tank is just hooked up as a bypass to the other with either an on/off valve at one end of one tank, and another on/off valve or a one way valve at the other end of the same tank. Both plumbed in close to the compressor. You would just have to manually decide your choice of use for that project.

As Larry stated, though not so much a pressure issue, as it is a volume issue. If you compressor could not replenish the volume at the required pressure for your nail gun then you would run into nails not being set at the ideal depth. The larger volume of the larger tank would give you a longer run time at the volume of air needed to run the gun at the PSI you wanted before the compressor kicked on. The larger volume tank would also allow your compressor to catch up to your gun easier than the small tank if your compressor ran at a higher cfm@psi that the gun consumed.

But if you are just running brads and such and not several framing guns or half a dozen brad guns off the little tank, this won't be a problem and the faster time to usable pressure would deff make this idea nice.

Your idea of the two tanks in parallel like this is a good and interesting idea that is very doable.:thumb::thumb:
 
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