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What size air compressor is required to make a 100 pound sand blaster work efficiently? Is there some formula that can be used to figure this out? I have a borrowed 30 gallon that does not appear to have the capacity keep the sand flowing. I have changed tips, adjusted the sand flow lever and increased the tank pressure and only get it to blast for short times.

Any thoughts/suggestions?

Take the requirements of your tool and get a compressor that matches. For instance if your sandblaster requires 18 CFM @ 90 PSI you need a compressor that delivers a MINIMUM of 18 CFM @ 90 PSI continuous. Then you need to look at your supply line. If the blaster requires a 1/2" line and you're using the typical smaller homeowner grade line you'll never be happy with the results.

I have a 60 gal 3.5hp compressor and it cycles continuously when sand blasting at 95 psi. So, the bigger the better. I gave up on sandblasting and just had a pro do it, its just a nasty dirty and frustrating job.

what they said - my 100 gal 5hp compressor will just keep up with sandblasting running non-stop

Bill

The problem may be with the sandblaster you have. I inherited a blaster set up that kept clogging up i could only keep it running for 30 seconds or so, then have to stop and fiddle with the control lever for the sand flow and then restart it for another 30 seconds. I have a 5 horse, dual stage compressor that puts out plenty of air and 3 inline water separators.

Come to find out this blaster outfit had a 3/8 inch outlet in the bottom of the tank. I bought another outfit with a 1/2 inch outlet and hose and have had almost not problems.

You need to determine the CFM. Also, is the compressor a peak 5hp, or running 5hp?

Years ago, I took an extra tank and added it to my smaller compressor so I had more volume. I would still have to stop to take a break to let the compressor keep up, but it helped.

My 25 gallon, 5hp, 230v, single stage compressor keeps up with my 110# HF pressure blaster. I stop after about 50# to let the compressor/motor cool down.

You have to find the sweat spot on all the ball valves to get the HF blaster to behave properly. But, oncy you have it figured out, it works fine. The smaller the nozzle, the less air that will be used. Find the smallest nozzle that will not clog and replace it after each 100# of blasting, or buy an expensive carbide nozzle.

Also, I found that black diamond or black beuty blasting media would not work at all in teh HF blaster...clogs regardless of what I did. Clogged at media valve at bottom of tank.

The only thing I can add is about drying the air. Water seperators don't dry it, just remove water droplets. You need a dessicant dryer, about $30 from HF, or a heater dryer, like $200.
As soon as you have DRY air, it won't clog.
Also: make sure there's no tight junctions or narrowed orifices (1/2 inch lines have 3/8 inch narrowings).

MikeE, you probably don't want to hear this but it will be cheaper in the end to have it done by someone in the business. I spent money on a pressure blaster from Tractor Supply. Have a 7HP 80gal 19CFM two stage compressor. It will catch up and shut off but only for about 45 seconds. After buying it, buying the sand, wrestling with the clog ups I finally sold it for 100 bucks as soon as I finished my chassis and most of the body. It is just not worth it....at least to me.
Buy yourself a decent blasting cabinet for the smaller stuff and leave the big stuff for someone else.

Just my .02 but if your not set up good to do blasing you will regret it.

I agree with Achipmunk 100%.
I use my blast cabinet for small stuff and send everything large out to our local professional blaster.

Thanks for all the advice. This didn't appear too hard to start with, but is turning into a somewhat costly venture. I am going to give it another try, but I think it may turn out to be too much screwing around for fewer results than I expected. One of the reasons I started this was the cost of blasting, but I am thinking of going back to my wire wheel and angle grinder.

OK, here is what I did. I got some different media,and hooked it up to a large compressor. The system worked fine. The media is white sand and about a 100lb. compressor.

The point is well taken about the blasting cabinet, but I need to do the inside panels and wheel wells of my panel truck so I can do the body work. I am close to getting the floor out and then I will start blasting the areas I need to fix. After I come upm with a larger compressor that is.

One other possible solution is to use two compressors (output of the two compressors go to a tee fitting, and the output of the tee goes to the blaster). If the two compressors are setup similarly (on/off point settings) it works fairly well. Yes, one nice big compressor is best, but this works for me for occasional use. I understand that big industrial users typically have multiple compressors to generate enough volume. I could never get my blaster to work well until I setup the two compressors.

White sand? Make sure you use a good mask. Look up Silicosis.

I first heard about this disease as a kid visiting Virginia City, Nevada near where I grew up. They talked about how the miners breathed in the silica dust while drilling. All the saloons had spittoons on the floor, not necessarily for tobacco spit, but for blood that the miners would cough up. Eventually they would die of asphyxiation due to the scar tissue build up in the lungs. They added water nozzles to the drills to spray down the rock to keep silica out of the air.

Just one reason I decided not to do my own sandblasting.

jo,

Another point well taken. I spent a few hours pulling the floor out of the panel. Lots of nastiness in there rust, dirt, tar and who knows what else. I heard of a place that may be reasonable to have it done and primed. It looks to me that the reasons to job this out are starting to make a lot of good sense.