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Media & Blaster Nozzles

Discussion in 'The Tool Shed' started by BKinzey, Jan 17, 2007.

  1. BKinzey

    BKinzey 1/2 ton status

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    I'm buying a cheapie blaster, one of the $99 5 gallon types, from Northern Tool and thought I should get some advice.

    I'm going to use it mostly on the frame and cast parts for rust removal.

    I hear playsand is good to use but should I get a bag of medium aluminum oxide for some of the rusty cast parts?

    What's the difference in nozzle sizes? I thought I should get spares in the size I will use most.

    Should I get the abrasive strainer, $15, or will a steel mesh kitchen strainer work as well?

    Thanks
     
  2. rdn2blazer

    rdn2blazer 1 ton status Premium Member

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    play sand is not what you want to use. it is dirty and has moisture in it which will actually force moisture into the surface of the piece you are blasting on a micro level.

    Aluminum Oxide is probably the best bang for your buck. there are different media that will cut faster or last longer but cost more. all professional/industrial quality grits have gone through one or several drying process's to remove all moisture so as not to induce oxidation, with steel, rust.

    the last shop I worked at was a specialty coating shop specializing in hi tech aircraft and space technology types of coatings. we had 14 grit blasting cabinets of several sizes from small to big and one big walk-in unit that was 9X9X18 ft long.

    we used all kinds of different grit to blast our parts before coating. we used glass bead media, aluminum oxide, and other types too. I think we even used carbide media on some ocasions. we had to meet surface roughness requirements before coating parts. parts were subject to microscope inspection and proflometer surface roughness readings. the parts were cleaned in a vapor degreaser and had to be coated with in 1 hour from grit blasting.

    our grit blast cabinets had timers on just about every cabinet to shut the unit down when the media reached its life span. the media would be completely changed to maintain the proper surface roughness per spec. the grit would be fine for general use after that but not for parts for coating.

    aw man, see what ya gone and did, ya sent me off on a tangent about grit blasting media :D . I could go on, and on but I will stop now. get al. ox. in about 80 to 100 grit. 36 or 50 grit if your frame in really rusted. I prefer the corse stuff for fast removal, good luck.
     
  3. camiswelding

    camiswelding 1/2 ton status

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    home depot has washed and kiln dried blast sand .. 50# for about 3-4 dollars.. its way cheaper than alox.. and you can strain it once or twice.. then the sand has turned to dust....make a "booth" out of some 4 x 8 sheets of plywood, get all the crud out of it before you run it thru again or youll have fun unclogging lines
    the tip size really depends on your ability to deliver cfm... I have a similar blaster (american tricon) with a 5/16 nozzle (which is pretty large) and I use a 15hp compressor to drive it at 175 PSI/30cfm ... I can go thru 50 pounds in 5 minutes... but it really moves material

    Youll probably be running something like a 5-7hp compressor I imagine.. so keep your tips smaller.. hopefully you can see at least 120psi at 20cfm.. its gets pretty slow lower than that.. USE A GOOD water filter or even better a dryer.. has a huge effect

    make sure you wear the best breathing gear you can buy.. silica/alox/walnut shells/plastic.. breathing any of those blasted isnt good for you
     
  4. rdn2blazer

    rdn2blazer 1 ton status Premium Member

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    you can use this but ofcourse you will get more life out of AL OX. it will cut faster at the same pressure due to its sharp edges and shape. sand does not have much shape to it, its kinda close to round, where as AL OX is very irregular. AL OX does not decintigrate like sand will from the impact.
     
  5. BKinzey

    BKinzey 1/2 ton status

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    I'm thinking I'll get some of both. Most of the frame is in good shape. There are a couple of rust (pitted) places and I can use the AL OX there.

    I'm expecting waste because I don't have a nice cement floor. It's old asphalt:rolleyes: Not an optimum place but it's all I could get.

    I've got a shop vac to pick up the material.

    A strainer, should I buy one or will something else do?

    Thanks
     
  6. diesel4me

    diesel4me 1 ton status Premium Member

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    screen...

    We sandblasted many things at the junkyard with nothing more than sand we swept off the side of the street!.....sifted it through an old window screen,and dried it out by setting the metal bucket on a hot wood stove!..to my suprise,it worked rather well,we didn't have much trouble with clogging,and window screen seemed to be fine enough to filter out all the pebbles and other crud that would clog the blaster up...

    Of course the proper sand would have been better,but our boss was a tightwad,and rarely bought any,unless it was a classic antique of his we were restoring..but we used the window screen to sift it and it worked great--just tedious work,doing the actual sifting..one body shop I frequented used an old chef's flour sifter that had a hand crank, and paddles against a screen..worked great!..:crazy:
     

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