I picked up a blasting cabinet for firearms. It says it needs a 125 lbs of air. I know most say to blast at 60psi or less. I'm wondering how much of a compressor to go with. This is the only air I'll be using other than a paint gun and an air gun for blowing. How much cfm should I get?

mine needs 11 cfm at 90 lbs.... depending on what you're using for media, pressure will vary.. steel shot at 90 lbs will cut any rust away.. soda works on softer items...and glass beads about the same....

It will tell you on the cabinet; cfm and pressure.

a homeowner-grade compressor, like my 5-hp craftsman, is not rated for continuous duty. mine has the specs to run my cabinet, barely. in practice, I have to wait for it to catch up.

get more than you need. the compressor will last longer.

unless you are just doing small stuff 5 hp is to small. you must pay attention of cfm.

How big of a motor just determines how much you get to hear it run. If you are only intending to use this for an hour or so a month, if that, look into something in the 2-5 hp range and plumb another air tank into the line. Put a shut off valve on the extra tank and only turn it on when you need the extra volume of air. you can get an extra air tank or do what the farmers do and use a 100 lb propane tank.

Also, do not get an oil-less compressor, the noise will drive you crazy.

If you were planning on using air tools and stuff, a 6.5 hp compressor with a 15-30 gallon tank works adequately.

Also, check out your local craigslist.

Aaron

The one I was using in the shop in Wheatland is an Ingersoll Rand, 5HP, 81.1 cfm @ 90psi, 60 Gallon tank. I normally run it at 90-100 PSI. Certainly more than necessary for your intended use but is great in a production environment.

Check the dia of the nozzle the sand runs thru. The larger sizes use more air. Also add a regulator at the box. Some of the finer work needs less pressure.

I disagree with the extra tank idea. If your compressor is too small you will blast satisfactorily for a time then have to quit and wait for the compressor to catch up. An extra tank means you can blast longer but you have to wait longer. A smaller nozzle is a better answer.

I have 2 identical 5HP commercial continuous duty compressors. They have 80 gal tanks and have a true reading of 24CFM at 100lbs.
Rhys, you may want to double check your CFM rating.