Large Compressor - Build vs. Buy?

[dholly]

I need to sandblast and paint some old tractor implements, but the 20 gal. horizontal can't keep up with the air grinders, etc. as it is. Since I hate waiting on the cycle time but don't really use it alot, I hesitate to spend the big bucks on a big new 220v upright. Unfortunately, no luck finding a good used deal which leads to the question of whether building your own large compressor -economically- is feasible.

As a start, I can pick up the 80gal. high pressure air tank pictured for $150-200. In addition to the neck threads, it also has a bottom drain and two threaded side taps. What can I expect to spend putting a motor and compressor head on this tank? Is there either money to be saved or the ability to make a better compressor for the same $$ outlay if I pick this tank up?

Couldn't seach up a good answer so I'm throwing out to the community before I spend a ton of time researching a subject or making an expensive mistake. If it ends up being smarter to write the check, well, thanks for some direction...

 

[MrJimi]

A few things to consider here, can you get a larger storage tank ? that will help you some. And if you build one, you will need a tank, electric motor, compressor pump, pressure switch and a few other little items and you can find all you need at Surplus Center - Hydraulic Equipment Electric Motors they have good prices and good shipping.
And another consideration is a smaller sandblast tip to reduce the air going out
Now if you do build your own, you will have it your way.
I hope that helped some
Jim

 

[BTDT]

Don't know how much you want to spend, how often you will be using it, etc., but maybe if you can find one of these used it will make all the air you need, and you don't need a compressor tank.
AIRMAN 185 CFM For Sale at MachineryTrader.com

This came from machinery trader. Here is their link

Construction Equipment at Machinery Trader: Caterpillar, Komatsu, Case, John Deere, Volvo

Good luck.

 

[Egon]

A large air tank is nice but under continuous running conditions it's just may be another bubble in the pipe as you will be depleting as fast as you fill.

If your air compressor is larger and goes into a frequent stop start cycle the larger the tank the better.

It's sorta like picking the compressor/motor and sizing them to the tank. A continuous running electric motor has an easier life.

I would pick a compressor that is capable of meeting your highest volume demand on continuous run basis unless you get a system with unloaders.

 

[MrJimi]

Here is a good place to shop with numbers/CFM and the rest of that stuff
Enco - Guaranteed Lowest Prices on Machinery, Tools and Shop Supplies
It all depends on what you want/need

Jim

 

[George2615]

I think you would be better off buying the compressor assy. complete. If you're going to spend up to $200 on the tank and another $450 for a 2 stage 5HP compressor then another $200 or so for a 5 HP motor. You'll have $850 tied up and still have to assemble it, buy relief valve safety, misc. plumbing etc.
You might as well just buy a large CFM (5HP or more)complete compressor with 220V motor. Northern Tool has several industrial compressors in the 15-18 CFM range for $850-1050. Each have the 80 gal tank, 2 stage compressor, 220V motor, and at least 15 CFM. A second tank for reserve could be plumbed in for added capacity.

Just my opinion.
George

 

[SPYDERLK]

Im going to second George on this. I built my own and took my time putting together a lot of good deals and built a 20 CFM with a used 2 stage compressor. I just ran on a 9cfm single stage and waited to accumulate everything I needed. At this stage of life I would just spend the extra $700 over what I spent and get the integrated unit right now. I think youll want the 20cfm for sandblasting. Mine gets pulled down to about 80PSI over the long haul.
larry

 

[john_bud]

I think you are better off buying a 2 stage 5-7 hp unit with an 80 gal tank.

If you were to build one, why not use a old 4 cyl car engine on a stand? In the old days, there were kits that pugged into a spark plug hole for compressed air where you need it. (this goes back to the '40's). A dedicated system would run on 3 cylinders and use the 4th for air. Would take some cutting and welding to block off the intake manifold to the 4th cylinder and give it a dedicated filtered inlet. Same on the exhaust side. You would want a high flow cooler (AC condenser would work) to cool the compressed air so you can dry it. Some work, but doable. Decent 4 cyl carb engines can be had for a hundred bucks.

A 2.3 l pinto engine would give you 34 cu in per stroke, 1500 strokes / min. You could for sure run an air compressor ! But I wouldn't want to lay down a color coat with it...

Just a wild thought...


jb

 

[dholly]

Thanks for the thoughts. After checking all the parts places, I find motors are quite a bit more expensive than I expected. After pricing everything out I think George is right, buying is the better move for a 2-stage. Maybe putting a single stage compressor on the tank makes more sense if I don't really need the high pressure to run constant flow tools, particularly if I can scare up a used motor on the cheap. I don't mind a bit of tinkering to put it together and that stands a better chance of costing less than equivalent spec'd units from NT, etc. after shipping or tax. What about THIS compressor pump ?

13.6 CFM AIR COMPRESSOR - $100 New, DEVILBISS model 440006XKXO920 two cylinder air compressor. Cast iron cylinder section, aluminum head and crankcase. Oil bath splash lubrication. Integral oil sight gauge. Inlet air filter included.

SPECIFICATIONS

* Two cylinders
* Bore/stroke: 2.75"/ 1.97"
* 13.6 CFM max disp.
* 12 CFM @ 40 PSI
* 9.65 CFM @ 100 PSI
* 140 PSI max
* 1,000 RPM max speed
* CCW rotation
* 1/2" NPT port
* Use with 3 HP motor
* Four bolt base mount on 6" x 8" centers
* 14-1/2" flywheel, single "A" groove
* Size 8-1/2" x 9-1/4" x 14-1/2"
* Shpg. 36 lb.

 

[MrJimi]

Let me give you something to ponder on, when your out of sand your AC is catching up