Sand blaster vs. Compressor dilemma

Compressors don't have to be expensive. I scored mine on CL for less than $200, a 2 stage Champion Pneumatic 60 gallon, 3 HP/220v unit circa 1950. And man is it quiet!

I've not tried sandblasting with it yet but I don't think I'll have a problem.

 

I have a very nice TARHELL brand portable sandblaster, it was about 300.00 plus when bought 15 years ago...I have a 2hp 2cyl 20 gal Speedaire and a 4 hp C/H pro 20 gal hooked together and I can sandblast fast and efficient without stopping....the speedaire will out do the Campbell Hausfield. When my 49 fleetline is done will sell the C/H....Both are 120v units and C/H is a one cyl.

 

You do also want to run a pressure regulator on the cabinet. 60 to 80 PSI is enough.

I ran my cabinet, like yours, for years off a 3 HP Champion ex-gas station compressor. With the air supply regulated down the compressor cycles on and off. It makes more than enough air for blasting.

Like Tommy says, get a used one once and it will outlive you.

 

I have had a 60 gal twin cyl single stage 220 VAC 5 HP for over 25 years and blasted a lot of stuff with just a siphon pickup and tarps to catch the material but is slow work.
I recently found an older 2 stage 80 gal without a motor and pulley and had to play with motor pulley diameter to get the compressor speed within its operating range(RPM) after I bought a new 6HP motor at TSC. The drive and driven pulley diameter affects how fast the compressor will recover and might be a cheap way to "hop up" a 110 vac unit a bit. I initially stuck an 8 inch pulley on it to test for leaks and it sounded like it was doing 100 MPH but built tank pressure really fast. Adjusted to a 4. 75 inch pulley set and it now sounds more like 60 MPH and should be in the middle of the operating range according to the pulley calculators.

I would think you could up the compressor speed a bit and not worry about it coming apart but no experience other than above. Two large single stages seems to make sense to me if you have the room but spare tire tanks or propane tanks are pretty cheap now and could be rigged in parallel for more volume if you are stuck with 110 service.

 

It's the same amount of electricity/energy, just in a different format ratio of voltage to current.

 

Smaller nozzles help with a limited air supply, too.

 

There are a lot of different, and theoretically valid?, ways to rate an electric motor. That's how you can have a blender or vacuum cleaner with a 2 hp motor. Although efficiency can vary some, a motor's current draw is a good guide as to how much horsepower an electric motor really has. Compressor efficiency varies a lot from one unit to another. So, two different pumps driven by the same motor won't have the same air delivery.

I have a cheap Craftsman belt sander. I modified it to do certian jobs so I only use it when my "good" belt sander isn't the right tool for the job. The motor of the Craftsman ended up full on metal dust and quit working. I took it apart and cleaned it. Maybe I shouldn't be surprised, but it is the cheapest built electric motor I have ever seen. A friend has the same unit and ended up replacing the motor with a proper one.

 

The optimum drive ratio depends on the particular pump. Without overstressing things, you get the most air from a given pump when the motor is running close to it's max rated current draw. Pump efficiency goes down with increased speed, but you still get more air. Pumps have a max RPM rating. Some have a minimum speed rating too. You don't want to exceed either of those.

 

As has been pointed out, the air jet/orfice in the gun determines how much air gets used. With a good efficient compressor(old Kellog) a 7 1/2 hp unit can continuously run one blaster set up for pretty aggressive work. It cycles off and on while blasting. Adding a second blaster that uses less air, the 7 1/2 hp can't keep up with both units running continuously. But I also agree, a less efficient 7 1/2 hp unit wouldn't perform as well.

 

your sort of correct but you have to think of it like this, you can drive a lot longer with a big block v8 [ the engine equivalent of a sand blaster] if you start out with a larger size gas tank. yes the compressor will put out the same, but you filled more air before you even started. compressor may never catch up but it will not run out as fast.

 

Sandblasting requires a crapload of air,,as does HVLP spray guns...Get a compressor capable of 18 cfm @ 90 psi ,,nothing less. This one of mine is 3 cylinder single stage 220v. My neighbour was good enough to move it into the shop with his new toy.

 

Go to a compressor repair shop in your area, or hunt down shops going out of business. Buy a good brand used compressor, even if it needs a bit of repair. It will last years longer than the NEW cheap CHinese crap you'd buy at a box store.
Speed-aire, Quincy, Ingersoll

 

Flawed logic there.
if the compressor puts out 99 CFM and you are using 100 CFM, it will never keep up. At best you'll have a 20-30% blast time with a large enough tank while the compressor runs 100% of time.

Much the same way as if you were to sell $1.00 for $0.99 cents, you'll be broke soon. The more you start out with (tank size) the longer it takes. The more volume you sell (cfm usage) the quicker you go broke.

 

your analogy reenforces what i wrote, what good is a sandblaster if you have to stop to let it catch up? the more air in storage the longer you can go, and in the case of my pot blaster the compressor looses it's power just as i need to refill.

 

Yup this is what I have. Eaton V4 this thing rocks! If you what to do some sandblasting this is the thing to do it with. It doesn't even break a sweat. Mine is on an 80 gallon tank with an auto drain. Not the cheapest on the market but it is damn near bullet proof.