Air Compressor

[GeneralDisorder]

I looked when I was shopping. I was pretty much only looking at Quincys, IRs, and Craftsmans. and for the most part, a similar Quincy compressor to the one I got would have been in the $500 range.

 

Yeah - but the used compressor market is a different beast. That just indicates how well a product keeps it's value. People are willing to pay more even for a used Quincy because they know they can do an annual service on it and have basically new machine. I doubt you could even get any significant parts for the 20 year old Craftsman - their business model doesn't require supporting things that far out.

 

Buy a 20 year old Quincy, and in anther 20 years when it's 40 years old you'll still be able to get service parts for it. I just ordered parts for a 1965 QR-370 that's going in our rental fleet after being owned by a local parks department since the early 80's. It was making 60 CFM @ 125 psi when I tore it down .

 

GD

[mcbrat]

looks like I'm checking CL now... my compressor finally gave out on me. won't even turn on. it tries, and immediately blows a fuse...

it's a Coleman. oil-less, and was loud as hell

 

I was trying to use it to pull the wheels off my wagon, but I tried my Craftsman 1/2" 19.2V impact... worked nicely!

 

But I still have a twin tank Ridgid compressor like this one I can use for now

 

anyone ever reused the tank and put a different compressor on it?

[Scoobywagon]

Yes, I've transplanted an air head.

 

Works great. At some point I'm going to have to do it again.

[84gl]

I replaced the compresser on the one in our farm shop a year ago with the twin cly. job harbor fright sells works great only cost me $89 bucks too 12.5 cfm @ 125psi

[GeneralDisorder]

anyone ever reused the tank and put a different compressor on it?

 

Being as I used to build and rebuild compressors for a living - yeah I suppose I've done that a few times

 

On your old compressor - have you done any troubleshooting? It might be something simple like a start capacitor, etc.

 

If you can turn the air-end over by hand try taking the belt off and seeing if the motor turns over. If it does try spinning the motor as quickly as you can by hand and then simutaneously turning on the power. If the motor spins up that way but won't on it's own (or won't under a load) it could easily be the start cap has blown out.

 

If you do end up buying another machine - just strip the motor and air-end off the old tank and plumb it into the new machine with hard pipe or SS flex line. More storage capacity won't hurt you any. No sense throwing away an extra 20 gallons of air storage.

 

GD

Edited July 17, 2010 by GeneralDisorder

[heartless]

I replaced the compresser on the one in our farm shop a year ago with the twin cly. job harbor fright sells works great only cost me $89 bucks too 12.5 cfm @ 125psi

 

 

yup - we have that twin cyl. comp. too - only problem for us was the motor isnt big enough to have both cyls hooked up - we had to plumb one to just vent out in order to keep from blowing fuses!

it works pretty good this way believe it or not - just takes a little longer to air up.

 

one of these days we will get a bigger motor and get both cyls hooked up...

[mcbrat]

Being as I used to build and rebuild compressors for a living - yeah I suppose I've done that a few times

 

On your old compressor - have you done any troubleshooting? It might be something simple like a start capacitor, etc.

 

If you can turn the air-end over by hand try taking the belt off and seeing if the motor turns over. If it does try spinning the motor as quickly as you can by hand and then simutaneously turning on the power. If the motor spins up that way but won't on it's own (or won't under a load) it could easily be the start cap has blown out.

 

If you do end up buying another machine - just strip the motor and air-end off the old tank and plumb it into the new machine with hard pipe or SS flex line. More storage capacity won't hurt you any. No sense throwing away an extra 20 gallons of air storage.

 

GD

 

well, even before this last incident, one of the last few times I used it before, it was running okay, but creating a tremendous load, and tripping the breaker...

 

I've not had a chance to look at it yet... trying to get my '72 K20 ready to be my tow rig since I sold my Yukon... figure I need to get some miles on the engine before I decide to pull a car trailer.....

[GeneralDisorder]

well, even before this last incident, one of the last few times I used it before, it was running okay, but creating a tremendous load, and tripping the breaker...

 

That's fairly typical of cheap single-phase motor failure. Either partially shorted windings or possibly run capacity failure if it's equipped with twin caps.

 

Could be a number of things causing high amperage draw - pressure switch settings, discharge check valve issues, air-end valve issues, etc. But most are easily corrected. About the only things that will condemn a small machine like that is bottom-end failure or upper cylinder damage of the air-end (which isn't uncommon with the reed valve machines when the reed's break and end up inside the cylinders), or motor winding failure. Other than that it's generally a matter of fixing a control sub-system like a pressure switch or check valve, replacing a faulty reed valve assembly, or a motor capacity, etc. Usually it's a cheap fix if you know how to diagnose and repair them yourself. When I repaired them for a living we would tell people to buy a new one since the labor was more than the machine was worth but we fixed them all the time for ourselves and on our rental fleet machines

 

A few simple checks will narrow down what's going on and if it can easily and cheaply be fixed. If it does the job you need it to do and can be fixed with a $20 capacitor..... why spend the dough on a new machine?

 

I've bought several of these cheap little machines and given them to friends - bought two of the 20 gallon machines - one for $20 and another for $35. Operator error mostly. Belt failures, and I had one the guy claimed was locked up but it was just a bit of surface rust in the cylinders - shot some Yeild in there and turned it over - wiped it out and hit it with some oil. Fired right up .

 

GD

[Mak_incatt]

I really dont think what you say you want is going to meet your needs. I have a five HP, 60 gal. 220V, 11 cfm compressor that meets my needs, and I do run out of air from time to time. Over the years I have had smaller ones but they just dont cut it. If you just do occasional work then maybe, but not for most HVLP guns. HVLP guns have various cfm requirements. Most, even the cheap ones reguire more than 10 cfm.

[mountaingoatgruff]

I've got a 35g vertical Husky compressor that needs repair. The copper line from the compressor output to the check valve on the tank originally had a rubber seal under a brass compression fitting. It disintegrated after a less than a year of hard use. The machine has been collecting dust the majority of the time I've owned it. I'm using a 12g oil-free IR unit right now...huge downgrade.

 

I've been wondering if I could use a brass compression ring instead of the stupid rubber part to avoid future failure and if there's anything I need to know beforehand. The fitting at the top of the copper line has a brass compression ring, just wondering if there was a reason (besides cutting corners on manufacturing cost) for putting rubber on it's other end.

 

The compressor:

 

 

The output line and check valve:

 

Don't flame me for my junk moisture separator and busted air filter housing... I know, I know...

[GeneralDisorder]

No need for plastic there - just bend a new section of pipe and replace the ferrules with brass. Looks like a simple and cheap repair.

 

They may have used plastic/rubber to avoid spending more money on a flex line. That line really should have a flex joint in it. Having it hard-piped will eventually lead to stress fractures in the copper tubing. But whatever - it will work for a while. When it does break replace with a stainless braided flex-line.

 

GD

[mountaingoatgruff]

Thanks again, GD.

[1-3-2-4]

How often do we need to change compressor oil? I've had mine for about a year now but it's only seen maybe like 5-6 hours of use.

[NorthWet]

No need for plastic there - just bend a new section of pipe and replace the ferrules with brass. Looks like a simple and cheap repair.

 

They may have used plastic/rubber to avoid spending more money on a flex line. That line really should have a flex joint in it. Having it hard-piped will eventually lead to stress fractures in the copper tubing. But whatever - it will work for a while. When it does break replace with a stainless braided flex-line.

 

GD

Thanks, GD. My 30 yr/old Craftsman hobby compressor also has a solid line, and the constant vibration necked-down (by "wobble compression") the pipe at the lower fitting. I will certainly look for flex line.

 

This same compressor has also been tripping breakers for years, and recently just wouldn't start at all. I tracked it down to corroded contacts on the centrifugal "start/run switch" (I can't remember the proper name for it). Took the end off of the motor, dressed the contacts, reassembled. just like magic.

[GeneralDisorder]

How often do we need to change compressor oil? I've had mine for about a year now but it's only seen maybe like 5-6 hours of use.

 

Typically it lasts a long time - no combustion gasses, etc like a gasoline engine. The splash-lubed machines need their oil changed more often as they typically have a lot of metal in the oil compared to pressure-lubricated machines. At the shop where I worked we would do an intial fill of SAE 10 (turbine oil) and run it for 8 hours straight at 100 psi. Then drain and fill with SAE 30 and we would reccomend it be changed every 100 hours of operation. More often if the conditions warrant (high humidity/low temp operation, dusty environment, etc).

 

If you buy a new (quality) machine you should change the oil after the (relatively short) initial run-in period as there can be quite a bit of metal from the rings seating.

 

GD

[GeneralDisorder]

Thanks, GD. My 30 yr/old Craftsman hobby compressor also has a solid line, and the constant vibration necked-down (by "wobble compression") the pipe at the lower fitting. I will certainly look for flex line.

 

You should be able to get a flex line from any hose/coupleing supplier with NPT thread on either end. Then you can just adapt to what you have. You may consider replacing the tank check-valve at the same time - eventually the plastic check ball in them disintegrates - McMaster, Grainger, etc sell them.

 

This same compressor has also been tripping breakers for years, and recently just wouldn't start at all. I tracked it down to corroded contacts on the centrifugal "start/run switch" (I can't remember the proper name for it). Took the end off of the motor, dressed the contacts, reassembled. just like magic.

 

One thing that can really prolong the life of the single-phase motors and pumps with seperate start windings is to use the pressure switch contacts to cut the start windings as well as the power to the motor - this causes them to coast gently to a stop instead of engaging the centrifugal clutch as they spin down and using the start windings as an electric brake. This has the added effect that the contacts in the clutch are only arcing when they disengage on ramp-up and not on spin-down.

 

GD

Edited December 11, 2010 by GeneralDisorder