Air compressor size for sandblasting

[spartman]

I am wondering what would be considered a good sized air compressor to use with a sandblaster?

I have a smaller sized unit with a 3 hp motor and dual pistons, but the tank is only about 5-10 gallons?

I don't think it would be enough to run a sandblaster but I could be wrong.

I have never had a blaster so I don't know what they take for air.


Thanks all for the answers.


BTW: If you haven't noticed I am a newbie here so be kind please.

[FORDification]

We'll take it easy on you....for a little while, at least!

One of my favorite quotes, and one I TRY to live by, says:
"It's better to have it and not need it, than to need it and not have it".
This is especially applicable with air compressor selection. Always buy more compressor than you think you'll need, because if you have it, you WILL use it.

The most commonly-made mistake is the purchase of a compressor which is too small for the work to be done. In figuring what size a compressor you'll need, do some research. Air compressors are rated by horsepower, pressure and CFM (cubic feet per minute of output at a given tank pressure). If you really feel that you need to own a compressor (rather than possibly renting one for a specific job), the only sensible way to purchase one is to first decide which tools you are going to use with it! Each type of air-powered tool has requirements for air pressure and CFM. The general rule is that the compressor should exceed the CFM of the largest tool by 1.5 times. If you plan to run more than one tool at a time off the same compressor, add the CFM's of the tools together before multiplying by 1.5. Proper compressor sizing means longer life, since it will never be overstrained.

A 60-gal upright compressor with a single-stage pump and a 5½-hp motor might seem like the ticket (or even a little bit of overkill) for the home user, but when you start looking at the CFM (cubic feet/minute) this compressor is capable of, you'll see that most are rated in the neighborhood of about 10-13 CFM, which for the most part is inadequate for sandblasting or painting. This type of compressor (like mine pictured below) is about the best single-stage compressor you're going to find, but a dual-stage compressor (with two pistons) will not have to work as hard, minimizing heat and water buildup in the compressed air. For the financially-impaired, the single-stage compressor CAN be made to work adequately, however...providing the user take frequent breaks to allow the compressor to catch up and to cool off. If the compressor is running full time, it's too small and will burn up in no time at all.

Certain types of tools, such as nailguns or impact tools, use short bursts of pressurized air and do not need a high powered, high volume compressor to function properly. Other tools such as grinders, sanders, sandblasters and drills need a continuous flow of air and thus need larger, more powerful compressors to work properly.

Another important factor to understand is what is known as the "duty cycle". The duty cycle is how much time the compressor can safely run within a given period of time, expressed as a ratio. For example, a common duty cycle for compressors is 50/50, meaning that the compressor motor can run about half the time it is supplying air to your tools... 50 minutes on and 50 minutes off. During the "on" time, the motor is pressurizing the tank. During the "off" time, your tools are running on the air stored under pressure in the tank. If your tools are draining the pressure off too fast, the compressor engine must run at more than a 50/50 rate which can lead to overheating and significantly shorten compressor life.

Pictured below is my compressor. It's got a 7HP motor with a 60-gallon tank...and I find with my sandblasting I still have to take fairly frequent breaks to allow things to catch up and cool down. I run a squirrel-cage fan blowing directly onto the motor & pump which helps lower the temps dramatically.

[spartman]

Thanks for the reply!

The compressor I have was my dad's and he only needed it to inflate tires and occasionally run an impact wrech.

It is a good unit and when I get out to take a look at it I will check the specs on it.

Here is a thought. Would it be possible to use the compressor unit I have and simply buy a bigger tank for it?

Thanks for taking it easy on me so far. I hope to have this truck going sometime before the next pres. elections.