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  • Sandblasting questions

    Hi,

    I am trying to set up a reliable sandblasting configuration. I have a Sanborn 30 gallon air compressor that can provide 150 psi and I believe provides over 7 cfm at 90psi. I also have one of those cheapy pressurized pot blasters; the kind that connects to your air compressor, loads the sand from the top and delivers the sand out of the bottom via a 6 foot hose. What I'd like to know is if there is a way to augment the air supply so that I can blast longer? Currently I can blast for 30-45 seconds and then the pressure drops too much to be effective. Is it possible to put in a secondary tank to hold over my 30 gallon while it recharges?

    Also, the gun that is on my unit is junk; its kind of bulky to use. Does anyone have a suggestion for improving the gun setup?

    Thanks in advance, J

  • #2
    Re: Sandblasting questions

    Originally posted by JayNak View Post
    Hi,

    I am trying to set up a reliable sandblasting configuration. I have a Sanborn 30 gallon air compressor that can provide 150 psi and I believe provides over 7 cfm at 90psi. I also have one of those cheapy pressurized pot blasters; the kind that connects to your air compressor, loads the sand from the top and delivers the sand out of the bottom via a 6 foot hose. What I'd like to know is if there is a way to augment the air supply so that I can blast longer? Currently I can blast for 30-45 seconds and then the pressure drops too much to be effective. Is it possible to put in a secondary tank to hold over my 30 gallon while it recharges?

    Also, the gun that is on my unit is junk; its kind of bulky to use. Does anyone have a suggestion for improving the gun setup?

    Thanks in advance, J
    JayNak;
    Your Compressor is too small.. You NEED a real Five Horse motor operating a Twin Cylinder, Two Stage compressor, (that puts-out about 17cfm) sitting atop a 60gal (min) or 80gal (preferred) vertical tank AT A MINIMUM!! A Seven to Ten HP motor is better! Use a Baldor or this caliber of motor.. Those little chinese motors that look like a 1/8hp that have a half dozen capacitors bolted to the outside are total junk.. How they can "claim" they are five horsepower is beyond me!!
    My compressor, bought twenty years ago, is as described above.. I have done entire car bodies and chassis with it.. The key thing is to produce enough "CFM" so the compressor "stays ahead" of the blaster's consumption..
    You mention having a "Pot" pressure blaster, you claim the "gun" is junk.. No where did you describe how big (quan.) the blaster is, NOR what type of "gun" you have.. I bought a pressure blaster at a car parts show, some twenty years ago.. It's capacity (of sand) is about 100lbs, but I can "pack" about 130lbs into it! The "gun" isn't.. It is a Ceramic Nozzle that
    is controlled by a "Ball Valve" lever that is either open or closed, no in betweens.. The Ceramic Nozzles are about 4" long and come in different inside diameters, depending on the output (CFM) of the blaster/compressor combination. As the inside of the ceramic nozzle wears from the high-speed sand, the speed at which the metal is cleaned deteriorates, thus takes longer. These are a consumable, so they WILL need replacing regularly, depending on how much you sandblast.
    So, to your question about adding a secondary tank to "hold you over", you can, but you are pounding money down a rat-hole!! YOUR Compressor ONLY produces air at a set rate.. You can have a 500 gal tank, yes, it might "allow" you
    to blast a little longer, but you will have to wait even longer for your compressor attempts to re-fill THAT tank.. Not worth a **** if you are blasting something that may take eight hours to blast and you spend OVER half that time "waiting" on the compressor to "catch-up"!! As I mentioned, my compressor "cycles" on and off while I'm blasting.. In short, I cannot "out run" it, and THAT is the minimun of how much compressor you need. Optimally, you want the compressor "resting" at least twice as long as you are blasting (constantly)! A longer "rest" period will keep your compressor "alive" longer!
    You also failed to mention (1) what you are blasting, (2) the media you are using, AND (3) the Output Pressure (PSI)
    you are using.. I blast car parts, bodies, frames, every metal piece. I use, on average, about 80-90PSI (at the regulator)
    for "hard parts" like the frame, suspension parts, etc.. I drop my pressure to 40-50PSI to do the sheet-metal.. I also "shoot" at a low angle, about 60 degrees.. blasting at 90 degrees (perpendicular) WILL cause heat warping! I also use the finest (smallest) grit I can find.. Here in Texas it's "#4 Blasting Sand.. I buy a pallet-load of thirty 100lb bags at a time (Yes, that's 3000 pounds of sand!!) I'll use "new" sand to blast those "hard parts" I mentioned, until I'm just over HALF finished, THEN I sweep-up all that once-used sand (I have a dedicated space JUST for blasting) then (recycle) use it again! Once I'm finished with the "Hard-Parts", I sweep-up the (now) twice used sand and put it into Steel 55 gallon drums (the reason I avoid plastic is the barrels are IN the sandblast area, I don't want to "blast away" the barrels holding my sand!!) I will NOW used the "twice used recycled" sand to do the body and sheet-metal parts of the car. The twice-used sand has been "beat-down" into an even "finer" (smaller) grit.. The blasting is a little slower, BUT, if done correctly, will not gouge nor heat-warp the body sheet-metal. Likewise, this twice-used sand get's used a couple more times.. By now, it's almost beat-down into dust.. I use this "almost" powder to blast the interior "Garnish Moldings" (around the windows in '50's & '60's era cars) and well as the dash and other painted trim parts.. This produces a fantastic "satin finish" that holds paint/powder well and without causing visible damage to these delicate parts..
    Lastly.. Water/Oil Filters.. I have two outlets on my compressor tank, one is plumbed with a 1/2" outlet, the other a
    3/4" outlet (this being the sandblasting side).. BOTH outlets have large Water/Oil Filters. I have three air connections in my shop, each has it's own Regulator with a Water/Oil Filter. My Sandblaster has it's own third water/oil filter.. The LAST
    thing you want is to "shoot" oil & water on a freshly blasted part.. It WILL rust before you can clean it, and oil penetrates the surface of bare metal faster than you could believe.. and you will ONLY find out about AFTER the last top coat of paint has dried, as the paint will peel off like masking tape!! Also, "Drain Down" your air-lines and "bleed" the water out
    of your compressor tank every day of use.. No exceptions!! Water collecting in the bottom of a compressor tank WILL rust-out the bottom from the inside out!!
    Hope this helps..
    Charles

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    • #3
      Re: Sandblasting questions

      Excellent post and advice and info by Charles.

      If you are planning to only blast small parts for plating such as nuts and bolts and screws, etc., I recommend you buy the Campbell Hausfield suction type blaster nozzle. Your compressor might be big enough for that nozzle. That is what I use for blasting parts for plating. I have a pressure blaster but I have never been able to get it to work reliably. I have a single stage 5 HP compressor which I chose instead of the two stage because of the air capacity. It easily keeps up with the suction type blaster.

      Jerry Hudgens

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