PDA

View Full Version : 2HP 220V Compressor + Sand Blast Cabinet = ???



LarryLarry
06-08-2016, 04:44 PM
I'd really like a blast cabinet for parts cleaning. Although I could use a wet parts cleaner for most of it...I think a cleaning dry blast from a blast cabinet would work better. I have an old belt driven 2 cylinder, 2hp, 220v compressor. I think 20 gallons. It says you can use it for paint spraying. I don't know whether it would be enough for a blast cabinet though. Would I get any performance worth the investment? I am sure my compressor is within the specifications of the benchtop or even small stand alones...but would I get good blasting or will it be mediocre at best?

mla2ofus
06-08-2016, 05:01 PM
I've never seen a 2 HP 220v compressor. Not saying they don't exist. Rather than gallons you need to think of the cubic feet per minute(CFM) rating of the pump.
Mike

131re
06-08-2016, 08:37 PM
Larry
Don't know how you are defining 'performance' but, most sand blasters want to see a minimum of 70psi and typically want 90psi for proper operation. I have and use a pressure fed sand blaster, with a 1/8" nozzle, my 7.5 hp Two stage compressor with an 80 gallon tank can just keep up with the demand. Smaller orifices tend to plug up at least that has been my experience. Your 2hp is going to be a single stage compressor- so it will max out pressure wise about 120ish. So you have about 30-50 psi to play with now that sounds like a lot, BUT Volume becomes a factor you have 2.67 cu ft of air in terms of volume for that tank at each 'atmosphere' in other words for every 15psi in the tank you have 2.67 cu feet of air. So if you need 90psi to make it work and the unit pumps up to 120psi, you have about 5.3 cu ft of air- If the blaster needs 5 cfm you'll run about a minute and then be out of air, unless the compressor can keep up. Rule of thumb is 3cfm per true hp. So you MIGHT have 6 cfm- probably more like 4 to maybe 5 cfm at 90 psi (as pressure goes up, efficiency of compressor goes down) So you are probably going to get starved for air in no time. If you give some specifics of the compressor and the needs of the blaster can crank out the math for you to see how long you can blast.

Pipeliner
06-08-2016, 10:10 PM
Low CFM nozzles are still going to eat 6-7 CFM and your average siphon gun cabinet is going to want 12+ CFM. Imagine using a rubber tip blowgun and holding it wide open. How long does it take to cycle the compressor on / off. Not long. You'll also get into moisture issues. I'm not trying to deter you, but serious bead blasting takes serious amounts of air. There are several things to be taken into consideration though. If you're wanting to blast a few nuts and bolts or a Marvel Schebler carburetor body, you'll probably get it done. But if you want to blast a rear fender off your 8n Ford, you'll be grossly underwhelmed.

LarryLarry
06-09-2016, 02:32 PM
Thank you for the information all. The parts I imagine blasting would be power steering pump size and smaller.

Here is the compressor detail. It is a Sears Craftsman model 106.154780

I can't seem to find much on it but that is what I have written down as the model number. 220V 2HP 150PSI I believe. Maybe I am wrong about the HP but I remember seeing 2HP on the motor itself.

pin2hot
06-09-2016, 03:37 PM
Here is the compressor detail. It is a Sears Craftsman model 106.154780

I can't seem to find much on it but that is what I have written down as the model number. 220V 2HP 150PSI I believe. Maybe I am wrong about the HP but I remember seeing 2HP on the motor itself.I have a similar compressor. Sears (not Craftsman) 106.173780. It is 20 gallon 2 cylinder single stage with a 2HP 230 VAC motor.. This was from around 1975 before the marketeers started playing around with Horsepower numbers. It was set to run from 125 to 150 psi when I got it. I no longer need the higher pressure so dialed it back to about 100 to 125. The mfr's opinion says, "A spray gun requiring 7.0 cfm of air or less at 45 lbs. of pressure can be used with this compressor."

greenbuggy
06-10-2016, 03:23 PM
I've never seen a 2 HP 220v compressor. Not saying they don't exist. Rather than gallons you need to think of the cubic feet per minute(CFM) rating of the pump.
Mike

To get technical, he needs to think in terms of CFM at the pressure he wants to run his blast gun at. More "gallons" will give him a hedge against running out of pressure and the compressor cycling again, but ultimately will also mean longer compressor run time before the air reservoir is full again.

Some quick googling says that 1 cubic foot is equal to 7.48 liquid gallons of capacity.

OP, how big of parts are you wanting to blast? If we're talking a minute or two of blasting you might not be so bad off. But I guarantee it will get old if you need to run for 15 minutes of continuous blasting. You can extend your usable air by daisy chaining a nice big air tank in between your compressor and cabinet, but ultimately you will probably want a 5 or even 7.5 HP 220V oil-lubricated compressor with a nice big tank.

You can figure on 1 HP being equivalent to roughly 3-4 CFM of capacity at 90 PSI.

I don't ever run out of air...but then again my compressor has a 4 cyl gas engine and about 50 HP. Need every bit of it too, for a 6 CF Clemco blast pot and a cabinet I made out of a 500 gal fuel oil tank.

MinnesotaDave
06-10-2016, 04:24 PM
I run my sand blaster off 7.5 HP twin stage 80 gal and plug in one or two 5 HP roll-around compressors too.

As stated by others, it's about CFM ratings.

And I don't like to wait for stuff to fill back up so I plug in the extras to keep the CFM where it needs to be.

tinker001
06-14-2016, 08:07 PM
To get technical, he needs to think in terms of CFM at the pressure he wants to run his blast gun at. More "gallons" will give him a hedge against running out of pressure and the compressor cycling again, but ultimately will also mean longer compressor run time before the air reservoir is full again.

Some quick googling says that 1 cubic foot is equal to 7.48 liquid gallons of capacity.

OP, how big of parts are you wanting to blast? If we're talking a minute or two of blasting you might not be so bad off. But I guarantee it will get old if you need to run for 15 minutes of continuous blasting. You can extend your usable air by daisy chaining a nice big air tank in between your compressor and cabinet, but ultimately you will probably want a 5 or even 7.5 HP 220V oil-lubricated compressor with a nice big tank.

You can figure on 1 HP being equivalent to roughly 3-4 CFM of capacity at 90 PSI.

I don't ever run out of air...but then again my compressor has a 4 cyl gas engine and about 50 HP. Need every bit of it too, for a 6 CF Clemco blast pot and a cabinet I made out of a 500 gal fuel oil tank.

I guessing to that you do not need a tank for it either. But do you not think that 50 hp is a little much for just sand blasting in a shop size blasting cabinet ? But do have to agree that you should never have to run out of air. Because you should have enough for two sand blaster at once.:jester:

greenbuggy
06-15-2016, 08:58 AM
I guessing to that you do not need a tank for it either. But do you not think that 50 hp is a little much for just sand blasting in a shop size blasting cabinet ? But do have to agree that you should never have to run out of air. Because you should have enough for two sand blaster at once.:jester:

Absolutely, a portable 150 CFM engine driven unit is way overkill for a shop, thats why I recommended a nice oil lubricated 5- or 7.5 HP electric with a big tank

mla2ofus
06-15-2016, 09:44 AM
I've never heard of having too much CFM of air. If the owner wants to burn fuel for that so be it.
Mike