air compressors

[linmictil2]

Afternoon Gents: I am in the market for an air compressor. I want it for blasting and painting. No big jobs,just mostly bikes. Question is--what size should I be looking for. Would a 20 gal. be enough.? I would like to get away with the smallest possible. Can you folks please inlighten me??? Thanks Mike

[ed1965dream]

Blasting takes a tremendous amount of air. A 20 gal compressor might be good for tire inflation and powering a paint sprayer but for blasting you are going to need more air. Here is a chart that will help you determine what sized compressor is required based on the blasting equipment being used.

http://www.mediablast.com/air-usage.php

[Goodysnap]

Ed's right. Sandblasting takes alot of air. I have a 60 gallon upright from home depot and it runs cont. using a die grinder. Its not just the size of the tank but cfm. Too small can leave you frustrated if your trying to be productive.

[conbs]

I have a 26 gal Huskey. I have used it a good bit for a small blast cabinet and it won't quite keep up. But, I find I take my time and stop to look at the part I am blasting pretty regularly. Waiting for the compressor to catch up while you are blasting might seem like a frustration to some, but for me, it makes the process more therapeutic - which is what I am after. These bikes are a hobby for me.

I also intend to paint with this compressor, but haven't actually sprayed a drop yet. That might change my mind. Waiting for your compressor to catch up could potentially screw up a paint job. Still, I am not that concerned when it comes to painting these bikes because there are just not many big surfaces to worry about. I could change my mind when i get there, but I think it will work for me. If you are painting a car, that will be different. The good news is that it doesn't take long for my tank to refill. In the end, I am probably more likely to create issues with a paint job from poor technique as I am from compressor issues. That is part of the learning process that is unavoidable no matter what size compressor I have.

For the difference in cost between compressor you'll never have to wait on vs a small compressor that doesn't take much room and is pretty cheap, a guy could buy a lot of paint for redo's. Now, if you are going into business or doing this all day every day, that would be a different story. One man's perspective and others may disagree.

[mobilyte]

if you're planning on using a compressor for blasting, the most important spec will be the cfm rating at the desired psi, i.e. how much air it can move per minute.

[conbs]

Mobilyte is right about the CFM rating. My Huskey is 6.6 @40psi. But, nozzle size and the type of medium will make a difference as well. Using a smaller nozzle for blasting will allow a smaller compressor to keep up a little better, but slows down the rate at which material is removed. Also, for softer metals like aluminum, the pressure needs to be lowered which allows the compressor to keep up a little better as well. Generally, I have found that I set my pressure at the lower end of the recommended range for all blasting.

I got my compressor years ago for general shop work and using smaller pneumatic tools. So, when it came time for a blast cabinet and paint gun, I was probably more interested in not havig to buy a new compressor if I didn't need to. If you are buying your first compressor you probably want to spend more time contemplating what you might or might not need. I would also recommend reading as much as you can about cfm rating for the tools you will buy and jobs you will undertake. You can buy a smaller blast cabinet and paint gun that will work well at lower CFM, but you will need to go slower.