Compressors and storage tanks

[raffaelli]

I have been using a 30gal oiless compressor for abiut 6 years now. I have over used and abused with grinder and cut off wheels the entire time. It finally decided to quit. Till I figure out what I want to do, I am using the 30 plus another 30 as storage tanks run off a 2 gal pancake. Surprisely that set up has held its own, but runs short in about 20 seconds with the cut off wheel. The pancake is not very happy about its new use.

I use regular car shop tools, plus cut off, grinder and chisels. I am going to give a try at HVLP in a few weeks. I dont have a blasting cabinet, but can see one in my distant future. My sanders are electric.

I have 240v if needed.

What compressor do I need? I would like to spend as close to zero as possible.

I have been eyeballing a 29 gal, 2 hp, 5.9 cfm at 90, 7.3 at 45. I would get that and add the 2 30gal as extra storage.

I have read on other forums that adding storage is a bad idea. True?

The CFM listed above seems a bit low for paint and cutoffs but I have been working with a similar compressor and storage tank setup in a buddies garage painting a car without running out of air.

I know the easy button is to go get a 16cfm 5hp compressor, but would like to maximize my bang for the buck and get only what I need.

Whatcha think?

 

[DIC]

Push the easy button and get a 2 stage.. Sell the other ones

 

[Cyberbear]

Based on your description of CFM needs, it appears that you are actually using more air than you think, and will possibly be adding more usage in the future.
There is no free lunch when it comes to a respectable air supply. Another thing to consider is that manufacturers of discount air compressors design them to operate at a 50% duty cycle, which means half hour on and half hour off. When the run time is exceeded, it can result in early a/c failure, even voided warranties. Adding left over tanks to the system for additional volume can cause the compressor to over heat due to extended run times when topping off the system.
Striking a happy medium is best and you should consult the a/c manufacturer and see what they recommend for your particular normal usage. Just my opinion from someone that has used up several compressors due to over use because I couldn't afford a suitable sized unit.

 

[C96]

I know the easy button is to go get a 16cfm 5hp compressor, but would like to maximize my bang for the buck and get only what I need.

Whatcha think?

Sounds like you already know exactly what you need. Stop putting it off, bite the bullet and get the 5hp compressor, a good 2 stage unit with 60 or 80 gal tank.

Stay away from the cheap “SPL” rated motors and the 3450 RPM motors. Get one that has a 184T frame 1725 – 1750 RPM motor with a mag starter.

All cast-iron pump running 900 RPM or less is best along with disc valves (not cheap reed valves).

You’re going to have to put out the bucks, but you won’t regret it.

You can always find a decent used one with the good qualities mentioned above if your patient.

 

[72Anthony]

There is no free lunch when it comes to a respectable air supply.

I think that is the quote of the year when it comes to air compressor sizing!

If you are going to get into sand blasting a 2 stage, 5HP, 80 gallon is the minimum. General consensus here is to move to a 7.5HP if you are going to be performing a lot of blasting.

 

[raffaelli]

I have an opportunity to get a used Mac Tools compressor 5hp 80gal 16cfm. Owner says it works fine. Been sitting in a barn for unknown years. $500. Worth it?

 

[CNGsaves]

^ ^ Now THAT would be more appropriate for what you've been trying to beat out of those oil-less contraptions you've been running.

Go hear the 80 gal compressor run. Time how long it takes from totally empty to peak pressure like 140psi or 150psi. Bring along an air hog tool like air sander to draw down air, and see how quick it recovers. I'm betting you'll LOVE what it can do.

If all is good, price is about right and you'd be getting good score if you got price down into the $400's . . . . . hey maybe you do end up paying $500 but ask if he can "Sweeten The Pot" by throwing in other air equipment like hoses, tool, etc. Good luck.

 

[raffaelli]

Owner sent me these photos

 

[raffaelli]

Is that an open joint where the tank transitions to the top bowl?

 

[CNGsaves]

Sheeesh !!!! You're gonna have to bring your oil-less compressor along to blow all that dust off the old girl !!!!

Also forgot that you've got to check whether he just left tank full of water. Open up drain plug and see if you get nasty rusty water out of bottom. If that happens, drive down the price as you'll need to do tank cleaning and investigation if it's safe.

Investigate that tank for potential problems. Drive down price if you think there are any safety issues, bad rust, etc.

As neglected as it looks, I'd say BARGAIN HARD and try for $250 to $350.

 

[raffaelli]

thank you for your help. I am nervous about purchasing a used compressor and having to fix it in short time.I have been looking at gallon 5 horsepower from harbor freight.it has similar numbers.

which one would you get

 

[RickP]

Personally, I decided on the HF 60 gal unit, because I didn't have time to find the perfect used one and fix it up. They also sell a refurbished version of that unit that's discounted $100 or so from the normal $799 price. I also got the 2 year extended warranty, but I've had zero problems with it in that time. It just runs. Its tank is made in USA, with an Italian pump, and I think the motor is from Mexico. I'm planning to hook it up to a spare 27 gal tank, which will make it similar to the 80 gal tanks on other comparable units.

For your needs, the used comp you posted looks pretty good, but you'd need to find the time to fix it up. Only you can decide what your time is worth. When I bought mine, I didn't have the time. But if I had to do it again today, I'd find a used one, simply because I have more time now.

Good luck! And post up some pics when you decide what to do.

 

[Bosque]

Another thing is see if there are any people or companies that work with Air Compressors. You may talk to them first and know that they will do a once over for you and fix anything that is bad. Get a quote of $100-$300?? Then pick up the used one, drop it off, pick it up fixed. Still cheaper than HF, and better.

 

[sberry]

Along with the no free lunch should be,,,, there is no substitute for horsepower.
Even some of the cheap comps,, as low as 500 or so and under a grand make lots of air. So what if it wouldnt last forever running 24/7,,, my bud with a hobby garage/farm bought a 60 gal thing from Sears 30+ years ago and it still works like new, got another one with a similar unit provided air for 30 yrs n a daily garage with 2 men.
Any money,,, for a "better" unit would have been a waste, wouldn't have helped them a bit, and its not over, both units still work.
The little 120V units are just too small, even entry level 60 gal is 2x as good plus the tank. They are a little like the 200 mig welder, in the same price range vs a 252 and they let one do most work,, just a little slower on the top end but for diy that's really so minor its not a deal breaker,,, so you got to wait 5 minutes a couple times a month.
Also one goes thru waves, at one time in my career hired in the shop, painted a couple dozen cars and trucks, half a dozen tractors and now havnt done an overall in several years.
Lots of sanding, now a box of discs last a long time and is used only in short bursts, the comps really sit idle 99% of the time. Couple cycles a day vs that per hour.

 

[Zrexxer]

Owner sent me these photos

Wow.

Worst pictures ever.

 

[A_Pmech]

Wow.

Worst pictures ever.

At least it was daylight out when he took the photos in his shed.

That thing is WAY over priced. It may have been a nice compressor when it was thrown in the barn, but it sure isn't very nice now!

Keep an eye out on Craigslist. Lots of good used compressors show up there for short money.

 

[raffaelli]

Thanks fellas. I am going to pass on it. I dont want to worry about the unknowns of it like inside tank condition. I dont want to find the time to mess with it. I am going back to plan A which is the 220v 5hp 16cfm 60gal from Harbor Frieght. If you want the contact info of the used compressor let mw know. It is in Ulster County NY.

 

[CNGsaves]

If you are "only nibbles" that the seller has had, I'd throw him a bone. Tell him you're really worried about condition of compressor and whether $150 would get you the compressor.

Price replacement tank so you'll know your potential overall cost invested in the compressor, if you find safety problems with tank and scrap it.

I'm still saying the used red compressor when fixed up WILL be better than anything you'll buy from Harbor Freight.

 

[raffaelli]

If you are "only nibbles" that the seller has had, I'd throw him a bone. Tell him you're really worried about condition of compressor and whether $150 would get you the compressor.

Price replacement tank so you'll know your potential overall cost invested in the compressor, if you find safety problems with tank and scrap it.

I'm still saying the used red compressor when fixed up WILL be better than anything you'll buy from Harbor Freight.

I will low ball him like that and see what happens.

 

[shannonw]

500 seems a bit steep for that just going by that pic.

Research who makes the mac pump and motor..it's not mac, surely rebadged something like my matco.

I'd also pay attention to the motors, price them out compared to what you're paying...even a cheap 5hp is not inexpensive if it goes...might as well replace the whole compressor on the common store ones (which is the situation i was in)

I couldn't find a decent priced low rpm one and was in a hurry (didn't want to do any work on it either) , did find an older matco (rebadged IR) 3450rpm 2 stage, common pump but apparently they put baldors on them back them (no idea about this motor but sure seems to run smooth)...still 3450 rpm thou

http://www.garagejournal.com/forum/showthread.php?t=219581
(paint and cleanup for grins)

The guy ran sand blasters off it so it had to be used pretty well and was still running like a top. I run sanders and polishers off it for a good bit, It's still noisy but most of the noise is the tank ringing.

if i was sand blasting though i suspect i'd want bigger. It still runs a good bit on sanders,polishers and i'm running pretty decent tools for those.

 

[sberry]

I'm still saying the used red compressor when fixed up WILL be better than anything you'll buy from Harbor Freight.

This may be true if the guy wants to buy a project. If he wants to use air at a low cost for a long time buy a new one, hook up, use today, most home shops couldn't wear one out if they tried.
The other thing aint pretty but some dust sitting on the thing didn't hurt it. We seem to think when people sell used old equipment they should polish it for us first. Like yall woud pay extra for that,,, hahaha

 

[Miss_Sissy]

I'm still saying the used red compressor when fixed up WILL be better than anything you'll buy from Harbor Freight.

So what? He may still be better off buying a compressor from Harbor Freight. He needs one that suits his budget and usage patterns. It doesn't make sense to sink a lot of money and time into refurbishing one that's designed for continuous duty in a commercial environment if all he's doing is working at home.

The issue with an old used compressor is whether it will cost more to fix up than it's worth. If you spend $500 for the compressor and then find it needs the pump rebuilt and a new tank, you're screwed.

The other thing aint pretty but some dust sitting on the thing didn't hurt it. We seem to think when people sell used old equipment they should polish it for us first. Like yall woud pay extra for that,,, hahaha

If a seller hasn't bothered to give it a few sprays of Formula 409 and wipe it off with some paper towels in the last five years, why should I trust that he ever drained the tank or changed the oil? While a clean machine isn't proof that someone did the proper maintenance, a dirty one is a pretty good indication that the seller neglected the machine while he owned it.

I keep all of the equipment in my shop clean and maintained. For the compressor, I blow the dust off with its own air. I check the oil level and appearance and change it if it is time to. I check belt tension. I close and reopen the ball valve on the compressor air output. I open the drain for a while until the motor kicks on and note the pressure. I listen as it fills for any odd sounds. When it shuts off, I check that it did so at the right pressure. I listen for leaks. I give it a once-over looking for any fasteners that might have vibrated loose. And I don't lean things on it that could damage the paint and give a place for rust to take hold.

Why should I view shop equipment different than cars? If I see a car that is covered in filth, I'm very suspicious about the care it got.

 

[CNGsaves]

^ ^ ^ Have no clue why Seller of that red Mac 80 gal compressor let it sit idle to gather all that dust.

Maybe the real owner died, and estate is just now getting to selling off stuff. Maybe husband died and wife didn't have a clue what hubby had in barn.

What I do know is bargains are often found in crisis . . . Virtually any old school 80 gal compressor will be better than anything you can buy at HF.

No way that OP can lose money if he throws bone and gets that compressor for $150 which he might. A little effort by OP might get him $1,000+ compressor for $150 and some work.

 

[Miss_Sissy]

No way that OP can lose money if he throws bone and gets that compressor for $150 which he might. A little effort by OP might get him $1,000+ compressor for $150 and some work.

Sure, but the seller is asking $500 -- and that's what I was commenting on. More power to the OP if he can get it for $150, though. I'd jump on it for that price.

 

[raffaelli]

Thanks for all the input. I appreciate it.

So the Harbor Freight 5hp is now in my garage. Going to wire the 240v 40a #8 in the morning.

Do I need to hardwire it or can I put a plug on it?

 

[CoopVA]

You can plug it...


Sent from my iPad using Tapatalk

 

[ms fowler]

When buying an air compressor, HP is meaningless. Air supply at some std pressure is the ONLY way to compare compressors.

 

[CNGsaves]

Thanks for all the input. I appreciate it.

So the Harbor Freight 5hp is now in my garage. Going to wire the 240v 40a #8 in the morning.

Do I need to hardwire it or can I put a plug on it?

Likely overkill to have 40A breaker and 8 gauge wire.

Post up specs on MOTOR plate . . . Sparky's will give you exact answer. Post PIC of plate.

As general practice, air compressor should be hardwired.

 

[raffaelli]

Its a 23a motor. Manual calls for a 40a breaker. To to me that means #8.

 

[redmondjp]

No need for a picture of the nameplate - here's a link to the HF unit in question:

http://www.harborfreight.com/5-hp-60-gallon-165-psi-two-stage-air-compressor-93274.htm

It's a 22A motor at 230V nominal. It will be fine cord-connected on a 30A circuit. I have a similar-size compressor plugged into my dryer outlet right now (got a gas dryer). There is no harm in hard-wiring it with 8ga wire on a 40A circuit either - it will have less voltage drop during starting but as stated, it is overkill for this unit.

I do agree with the advice to hard-wire a compressor in general, but for compressors with these smaller-frame consumer-duty 3.5-5HP motors on them (under 25A), cord-connected is not a necessity nor provides any advantage in my experience.

A coworker of mine just bought one of these used and rebuilt the pump on it. It will work great for the OP and provide all the air needed, but the aluminum pump is screaming along at 1368RPM so it is loud (in relative terms as compared to similar-sized more industrial type compressors with cast-iron pumps that turn slower). One suggestion would be to add a remote air inlet as a lot of the noise comes from there. Oversize the inlet pipe a size up and get it to a source of cool, clean air if at all possible.

Happy compressoring!

 

[Miss_Sissy]

I do agree with the advice to hard-wire a compressor in general, but for compressors with these smaller-frame consumer-duty 3.5-5HP motors on them (under 25A), cord-connected is not a necessity nor provides any advantage in my experience.

Like you, I installed a 30A, 3-prong dryer cord on my Puma 60 gallon 3HP compressor. I installed a mating dryer receptacle on the wall near the compressor. I prefer cords. I can pull the plug when I go on vacation. I can pull it when I'm servicing the compressor (e.g., adding an hour meter attached to the pressure switch). It's easy to disconnect should I need to move the compressor for access to something (like the copper air lines behind it). It's just a nice, inexpensive, quick-disconnect for the compressor.

 

[rodm1]

Sounds like you already know exactly what you need. Stop putting it off, bite the bullet and get the 5hp compressor, a good 2 stage unit with 60 or 80 gal tank.

Stay away from the cheap “SPL” rated motors and the 3450 RPM motors. Get one that has a 184T frame 1725 – 1750 RPM motor with a mag starter.

All cast-iron pump running 900 RPM or less is best along with disc valves (not cheap reed valves).

You’re going to have to put out the bucks, but you won’t regret it.

You can always find a decent used one with the good qualities mentioned above if your patient.

Most on this board need this or one with a 7.5HP motor.

 

[toyoguy81]

I wired my 60 gallon Puma to a service disconnect box. I used 10 gauge wire

 

[ltusler]

Thanks for all the input. I appreciate it.

So the Harbor Freight 5hp is now in my garage. Going to wire the 240v 40a #8 in the morning.

Do I need to hardwire it or can I put a plug on it?

Get some good compressor oil in it before you use too much.

 

[marinusdees]

If it runs.

 

[raffaelli]

So I opened the wall to route the power........and.......it turned from a simple bew circuit a few stud bays from the panel to a bigger project. I added a dedicated circuit for the AC, relocated the 240v welder outlet, relocated the electric heater and curcuit, made the cord for the compressor, added some pull strings of future, removed a bunch of slatwall to make room for new shelves and added blocking for the cooling cluster of compressor pipe. Notice anything missing? Yup, still no power to the compressor.......hopefully will pull that wire tomorrow.

I am using 40a #8/2.

If it runs.

Huh?

 

[RickP]

Notice anything missing? Yup, still no power to the compressor.......hopefully will pull that wire tomorrow.

I am using 40a #8/2.

That's exactly what I'm using for the same compressor (8 ga stranded in conduit). If you're only a few feet from the panel you won't need a disconnect for it - I just use the power switch on the compressor or the breaker. I'd recommend against using a plug - the rated HP on that motor is too big for a plug. You can get a pre-made electrical whip for an air conditioner that uses flex conduit for the last few feet to the motor.

 

[Wuaname]

I want to know what oil less compressor you were using that lasted that long and was so versatile

 

[Xicaque]

I'd skip that dust bucket and get a Quincy but that is just me.

 

[raffaelli]

I want to know what oil less compressor you were using that lasted that long and was so versatile

I was using a craftsman 1.5hp 30 gal vertical. It worked great for me. It built and maintained a race car plus lots of normal car and building stuff in the garage. In the past couple of years I have outgrown it. When it died I used it as storage and added another 30 gal storage. Both fed from an ancient 1.5gal huskey.