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Need help with my cheap, piece of crap HF sandblaster!

Discussion in 'The Hokey Ass Message Board' started by evintho, May 29, 2010.

  1. evintho
    Joined: May 28, 2007
    Posts: 474

    evintho
    Member

    Yeah.....I know. If I had an extra $450 I'd love to have the Texas Blaster! But that ain't happenin'. So.......90 lb. HarborFreight made in China turd. Clean, filtered, dry air coming from an IR 5hp 18cfm unit. Water trap 5' downstream followed by a second WT 25' ds followed by a MotorGuard 'toiletpaper' filter followed by another WT at the blaster. Playsand is dry and strained.

    Problem is the blast hose clogs up after 30 seconds of blasting. I've got 90 psi at the end of my airhose run. When I connect the hose end to the blaster, the gauge on the blaster reads 80 psi. As soon as I depress the deadman nozzle I can watch the gauge drop to 40 psi! That's probably the issue!:eek: Blaster has 3/8" ball valves, hose and fittings.

    I've got a frame, body, suspension and a ton of parts that need to be blasted! This cheap blaster's holding up the whole show!
    Any ideas? Any and all help is much appreciated!
     
  2. F&J
    Joined: Apr 5, 2007
    Posts: 9,228

    F&J
    Member
    from CT

    I never had the blast hose plug up. It is common to plug the nozzle, but it will shut off completely.

    That pressure drop to 40, how much time to drop that low? If fairly quick, I would guess restricted air supply to the blaster.
     
  3. x2 or faulty control (dial)
     
  4. Andy
    Joined: Nov 17, 2002
    Posts: 3,361

    Andy
    Member

    Do you screen you sand? You need to make a wire screen holder that will go over a large trash can. Always pour the sand thru the screen before using and always after too. The sand does not come sepereated enough to use in the small sandblasters
     
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  5. F&J
    Joined: Apr 5, 2007
    Posts: 9,228

    F&J
    Member
    from CT

    rethinking; Most pressure blasters have air pressure "on top of the sand" as well as an adjustable air vavle at the mixer. If you do have that adjuster valve, and if it is shutting off too much air to the mixer, then pure sand will try to come out the sand hose....with very! little air.

    To set it up on a fairly dry day, I leave the air valve to the mixer full ON, and sand shut off. Then open the nozzle while strating to open the sand valve. On my brand, I don't need to mess with the air valve going to the mixer UNLESS it's humid, and then it is needed to keep the sand flowing into the mixer.


    On what Andy said about screening (as a cause)...If my blaster gets a small piece of unscreened object mixed in the 80 grit pre-screened sand I use, that object will plug the nozzle completely, and real quick...not the hose.


    on more question, what size nozzle hole?

    EDIT: is this an open hopper siphon unit? or a pressure tank blaster???
     
  6. Jim Dieter
    Joined: Jun 27, 2008
    Posts: 390

    Jim Dieter
    Member
    from Joliet

    If your tank has a valve to turn off the sand, try shutting the sand flow down some. I run mine about half open, if I open it all the way it plugs like yours. Mine isnt a HF, but it's along the same lines.
     
  7. Jim Dieter
    Joined: Jun 27, 2008
    Posts: 390

    Jim Dieter
    Member
    from Joliet

    I should have answered faster, or slower...but F&J answered better. heh heh
     
  8. blt2go
    Joined: Oct 27, 2009
    Posts: 551

    blt2go
    Member

    does this unit have a metering valve on the bottom of the tank, for controlling volume of sand? also does it allow for controlling the air/sand mixture, with a valve that bypasses the tank pressure and gives full air to the deadman? if the answer to these questions is yes, then shut the sand off and open the airflow valve completely, then open deadman. if pressure stays in operating range slowly start to allow sand in to the mix. if the answer is no to these questions post a pic of unit. i use this rig with a 500 lb. schmidt sand pot. good luck.
     

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  9. blt2go
    Joined: Oct 27, 2009
    Posts: 551

    blt2go
    Member

    dang i type slow. good job guys.
     
  10. wbrw32
    Joined: Oct 27, 2007
    Posts: 4,619

    wbrw32
    Member

    I also have a HF blaster,,,I personally run much higher air pressure into it..more like 150-200. The valve on the bottom of resivor controlls the amount of sand coming down..do not run it wide open..DRY sand is a MUST..
     
  11. evintho
    Joined: May 28, 2007
    Posts: 474

    evintho
    Member

    Wow, quick responses! I'll try to answer all questions.

    Psi at the blaster drops to 40 in about 10 seconds!
    Yes, I screen the sand.
    It seems like there is too much sand and not enough air coming through the hose.
    I've got the 3/32" nozzle which is opened to about twice that size now!

    I open the blue air handle all the way. The red handle, adjacent to the blue is fully open also. I keep the red handle, on the bottom of the unit closed until I have full airflow then crack it just enough to start introducing sand to the stream. 30 seconds later the sand stops but the air keeps flowing.......at 40 psi!

    [​IMG]

    [​IMG]

    [​IMG]
     
  12. ARE ALL THOSE FILTERS AND DRYERS CUTTING DOWN THE FLOW??
    ops
    maybee need a reserve tank after them

    used my HF BLASTER THE OTHER DAY AND IT WORKED PERFECT

    what grit you using?? sometimes a worn out tip is better than a new one, more flow and less pressure to build heat and warp

    sorry on the screams was acciedntal:eek:

    I run the bottom valve on 1/2 way always
    is your sand damp? dump out the sand in tank and check it if is funky
    boy those HF units get cheeper looking every year had 2 now one long ago, atleast you can sell them easily
    I got a big TIP unit too but like the HF for quick and dirty little jobs
     
    Last edited: May 29, 2010
  13. I dont have the deadman valve but have got paper etc in hose and have had to remove the nozzel and blow the crap out , make sure all lines are clear of cardboard from sand and all lines are clear
    whats your humidity, if you need dryers??
    we are low humidity at present and just used line air

    I have a total of 140 gals in tanks on a 5 hp AND WILL GET THE PUMP HOT AFTER BLASTING FOR SEVERAL MINUTES , you may need more capacity on the tank
     
    Last edited: May 29, 2010
  14. stude54
    Joined: Jan 9, 2008
    Posts: 41

    stude54
    Member
    from michigan

    Just a thought, but when I have that trouble with my HF blaster that has done five cars, it is the sand. It's either wet or not filtered to a small enough size. Go buy a bag of blasting sand, crack the bottom valve about 1/2 or a little less open, put 110 PSI on it and blast the heck out of whatever you want to.

    Bob
     
  15. Painterdave
    Joined: Apr 30, 2010
    Posts: 14

    Painterdave
    Member

    it helps a bunch to use 1/2 inch airline with big fittings.. most japan crap hoses that are labeled 3/8 inch are 1/4inch in reality.. I paint for a living and trust me flow matters..
     
  16. Andy
    Joined: Nov 17, 2002
    Posts: 3,361

    Andy
    Member

    I would try closing down the red handle a bit. You are bypassing most of the air. If I understand it right, the sand clogs at the bottom of the hopper and the delivery line stays passing air? That right? Come down on the red handle.
     
  17. chopolds
    Joined: Oct 22, 2001
    Posts: 4,874

    chopolds
    Member
    from howell, nj
    1. Kustom Painters

    Woooow Nelly...did you say you had a compressor putting out 18 CFM??????
    Unfortunately, there are so many different ones, say 5 HP, that put out anywhere from 90 or more CFm to much, much less. What size holding tank do you have? What's the true CFM of air, say at 90 PSI? Some comps list CFM at low PSI's so they look more powerful than they are.
    If your pressure drop is that fast, I'd say you didn't have enough reserve air volume, and your compressor doesn't have enough power to keep up with the volume requirements! I have a cheapo blaster, and replaced the valves to better ones, and it works fine. You have to use clean, dry filtered sand for it to work, as well as dry filtered air...and enough pressure AND volume to flow the air.
     
  18. B Blue
    Joined: Jul 30, 2009
    Posts: 281

    B Blue
    Member

    Pressure dropping that fast means inadequate air flow. I'd remove ALL of the filter/traps and see what happens. I bet it will do just fine. Then add filters, one at a time to see which one is the culprit.

    Just curious, what is the Motor Guard filter? Is it one of the oil filters that used toilet paper? Why do you need filtered air for a sand blaster? My money says that thing is the problem. Filter the air on the intake side, that way it protects your compressor. I have an automotive filter on my compressor intake.

    Bill
     
  19. carcrazyjohn
    Joined: Apr 16, 2008
    Posts: 4,845

    carcrazyjohn
    Member
    from trevose pa

    I ve had no luck with playsand .Always clogs up for me .Try the real stuff.
     
  20. Black Primer
    Joined: Oct 1, 2007
    Posts: 967

    Black Primer
    Member

    Any moisture at all in playsand will cause it to "pack" and not flow. Its really not meant for blasting, and especially with a small hobbiest type blaster. As mentioned, try the real stuff.
     
  21. hotrod316
    Joined: Apr 7, 2010
    Posts: 25

    hotrod316
    Member
    from ohio

    mine 15 + years old, use the good stuff, it cheap, about 12 dollars/100 lbs - one tp filter, screen it, reuse it 3-4 times
    ps medium or fine my will not shot the heavy
    it will make a mess
     
  22. evintho
    Joined: May 28, 2007
    Posts: 474

    evintho
    Member


    It's not my source air. Ingersol/Rand 5 hp single stage, 80gal tank delivering 18.5 cfm @ 90 psi. I plugged in a pressure gauge to the female coupling on the end of my air hose. There's a constant 90 psi. As soon as I couple the air hose to the blaster, the gauge on the blaster reads 80 psi. As soon as I open the deadman, that gauge drops to 40 in 10 seconds. I bought the playsand from Lowes specifically because they store it inside. I sift all my sand. I truly don't believe it's damp.

    Constant 90 at the end of the airhose run, after 2 traps and filter. I use the MotorGuard filter to capture any last vestiges of moisture before the blaster.
    Here's my 'point of use' filter arrangement. Got a water trap 5' off the compressor then 25'-30' of airhose then this (that I secure to the fence), then 4' of airhose then it connects to the blaster.

    [​IMG]

    The problem is I drop 50 pounds of pressure once the air enters the blaster. I think maybe I'll upgrade to some 1/2" hose and fittings as suggested. I've already drilled out the manifold on the bottom of the unit 3 or 4 drill sizes, to no avail.

    Also, where would I get real blasting sand? What grit? What brand, etc.?
     
  23. stude54
    Joined: Jan 9, 2008
    Posts: 41

    stude54
    Member
    from michigan

    Any paint store, Tractor supply, most auto stores. I think it's less than 40 mesh but just get blasting sand.

    Opening up the fittings and other changes are beyond your compressor's ability to handle. As I said, get some good blasting sand, crack the bottom valve a little less than 1/2 way and blast.That thing ain't rocket science.

    Bob
     
  24. F&J
    Joined: Apr 5, 2007
    Posts: 9,228

    F&J
    Member
    from CT

    I don't know if I am reading it correctly. I am sure the guys who suspect air "flow" restrictions want you to test the actual CFM flow at the end of the lines.

    Easiest way is having the sand valve shut off so just air is coming out the nozzle. Then run it open with no sand and see if the blast tank gauge drops to 40 again.

    Other way to test without using the blaster is to put a gauge on a T right after the last filter, then use an open nipple from the quick coupler on the end of your 4 foot hose....then see if the last gauge drops real quick with an open air fitting.

    I get sand at Ace-True Value hardware OR look in yellow pages under sandblasting/supplies
     
  25. B Blue
    Joined: Jul 30, 2009
    Posts: 281

    B Blue
    Member

    If you have 90 psi at the end of the hose while the blaster is running at 40 psi, something in the blaster plumbing is plugged. Maybe the quick acting valve has an incompletely drilled orifice. Anyway, take the blaster back to HF. Let them deal with it. If taking it back is out of the question, disassemble and inspect everything that handles air.

    Half inch fittings will not solve anything unless one of your old fittings is partially plugged. A 3/8" hose will move as much air as your nozzle.

    Bill
     
  26. As with my bead blaster, too much media in the hopper will screw up the feed and flow.
     
  27. rramjet
    Joined: Dec 30, 2009
    Posts: 561

    rramjet
    ALLIANCE MEMBER

    I have to agree with those advising the compressor is not keeping up with air volume demand (CFM). Kinda like you got a big air leak. That's the only reason I can see for pressure dropping when the blaster is activated. Don't know what the blaster actually needs for outlet pressure to suck the sand but 40 seems pretty low.
     
  28. budd
    Joined: Oct 31, 2006
    Posts: 3,471

    budd
    Member

    i have a $400 blaster, i use proper blast media, i still get clogs, most times i just give the tank a good kick and the media starts flowing again, when the media starts getting low i have to shake the tank to get the media to fall down off the sides of the tank, at the bottm of my tank, below the ball valve that governs the media flow i have an X fitting, this allows me to do a purge out the bottom, comes in handy, i just remove the bottm bung and turn the air on till she blows clear, if it really gets packed in tight i can use a bent welding rod to kinda rod it out, i always turn the air on first and then the media. i use nothing to remove water from the air, you want all the air flow you can get.
     
  29. chopped 35
    Joined: Nov 19, 2009
    Posts: 61

    chopped 35
    Member
    from australia

    if the sand flow stops but you still get air coming out then pull the hose off the fitting at the bottom of your machine and see whats goin on in there. check for moist sand or maybe there is some other obstruction. i have a similar blaster and used to have a lot of trouble with it after just a few minutes. the fitting at the bottom of my machine was just a 4 way with a plug in the bottom hole. pulled that out after a few minutes and hey presto , a plug of wet sand. i have a water trap at the pressure pot. problem is compressing air creates heat. as the air cools it will make some condensation depending on humidity. as you are using a lot of air quickly it is still warm to some degree as it goes through the water trap creating some water after that point. only way to cure that is a dryer of some description. sharp changes of direction in the air lines and fittings in particular will help to make water as well. ever seen an f1 car race in humid conditions? you can clearly see the vortex of water vapour coming off the rear wing at the ends. a similar thing can occur in air fittings where there are sharp edges etc internally. a drier will be your best mate if you plan on blasting for any length of time. easily made out of copper pipe etc. see my reply to this previous post which explains that in a bit more detail.http://www.jalopyjournal.com/forum/showthread.php?t=426051 water may not be your problem at the moment but it possibly will be at some point.depends on the humidity in your part of the world on the day your using your gear of course. if you check out the pics i posted of my setup the cooler/ drier is a bit overkill. a mate made one out of and old stainless beer keg with the top cut off with a copper coil made out of three quarter copper line and it works a treat. a drop leg is a must have to catch the water it will make/collect. hope that helps ya out buddy i know what you are going through.:cool: :cool: :cool:
     
  30. That bottom manifold should be a venturi to "suck" the sand out of the hopper. What part did you drill out, the sand passage or the air passage? You may have killed the suction by removing all the backpressure at the venturi. That could explain the pressure drop as well. Of course, that's just a thoery...
     

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