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Thread: Funnel/Shoot for Custom Sandblaster

  1. #1

    Funnel/Shoot for Custom Sandblaster

    I'm looking to build my own sandblaster and see plenty of ideas online for plywood ones. I don't mind making the top out of plywood, but want the bottom part that serves to "funnel" the abrasive to the bottom via a square chute design to be metal. I want this to ensure easy drainage where the abrasive won't stick to the wood grain. However, I'm not a metal worker. I can cut some diamond shapes out of old washing machine sides with an electric shear, but I'm not sure how to join them. Then I thought of just using something like a range hood because it has the basic shape, but they aren't that deep. Does anyone have an idea for a pre-existing chute or something I can salvage and repurpose? If I could find a giant pyramid toy or some funny plastic dog house I could turn upside down, I'd even go for that.

    Thanks in advance for any ideas.

  2. #2
    The most unbelievable blasting cabinet I've ever seen was documented on a website by Dave Propst back in '05. While his website didn't have dimensions given, there was more than enough info available to design and build your own. Unfortunately, I just checked and the site is kaput. Fortunately, for me anyway, I saved the webpages dealing with the build, but I'd have no way to forward or repost them somewhere (even it were legal to do so). However, if you do a web search using "Dave Propst blasting cabinet" a Pinterest page will pop up giving some photos of the thing.

    The design of funnels can be quite involved and depends upon the size of the cabinet - and therefore the slope of the sheets - and the material you're blasting, ambient humidity and several other factors to facilitate "flow" of media to the pickup tube. The easiest way around this is to use a vibrator unit. At their simplest this is a small 1/3-1/2 hp motor with an eccentric weight on the shaft to induce vibration. Such beasts are expensive as they need to be designed to take the unbalanced load on a continuous or near continuous basis. There is a company in Cleveland that designs and sells them. They occasionally show up on eBay. Good luck.

  3. #3
    Join Date
    Feb 2010
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    Pueblo, CO
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    237
    I built one many years ago. What I learned was that working with sheet metal is much like working with paper. My suggestion is to mock up your funnel in paper or cardboard and then unfold it to use as a pattern. Scoring the fold lines to guide your folds helps a lot. You may have to add some tabs for the mechanical joints, but a few sheet metal screws and some sealant should give you a working funnel.

  4. #4
    Join Date
    Feb 2016
    Location
    Honolulu, HI
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    103
    You could build it from plywood, then "veneer" it with steel. I read somewhere (don't remember) that somebody used an oscillating tool to induce vibration into a container full of solvent, might be worth looking at for a chute.

  5. #5
    Join Date
    Feb 2008
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    E TN, near Knoxville
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    6,059
    40 years ago I made one by bending sheet metal:

    hopper_photo_1.jpg hopper.jpg

    This one was for a bit different purpose, the grit fell in the hopper and I put a nozzle in the bottom aimed to blow a jet of grit straight up. I used it to etch glass (both flat and curved) and clean spark plugs, both held against the foam rubber top. It was easy to make and should work fine for collecting grit for a sand blaster. My metalworking was crude but it didn't need to be pretty. The sheet metal can be thin gauge since little strength is needed. I used stainless steel since I had some on hand.

    I made a template first from poster board or something, cut the shape with hand shears, then made the corner bends with a hammer over a piece of wood, if I remember correctly. Sheet metal screws or pop rivets and silicone caulk would hold it together. Making it by bending one piece was easier than trying to join multiple pieces.

    JKJ


    Quote Originally Posted by Jamie Valentin View Post
    I'm looking to build my own sandblaster and see plenty of ideas online for plywood ones. I don't mind making the top out of plywood, but want the bottom part that serves to "funnel" the abrasive to the bottom via a square chute design to be metal. I want this to ensure easy drainage where the abrasive won't stick to the wood grain. However, I'm not a metal worker. I can cut some diamond shapes out of old washing machine sides with an electric shear, but I'm not sure how to join them. Then I thought of just using something like a range hood because it has the basic shape, but they aren't that deep. Does anyone have an idea for a pre-existing chute or something I can salvage and repurpose? If I could find a giant pyramid toy or some funny plastic dog house I could turn upside down, I'd even go for that.

    Thanks in advance for any ideas.

  6. #6
    Join Date
    Sep 2005
    Location
    Eagle, ID
    Posts
    46
    I'd go to my local HVAC shop with a sketch and I'll bet they'd do one cheap. With all the CAD stuff today, they could knock out something quick.

  7. #7
    Join Date
    Sep 2016
    Location
    Modesto, CA, USA
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    1,602
    Note the slope needs to be more then the angle of repose for your blasting media. I would say 45 degrees should cover them all.
    Something says plastic traffic cone to me.
    Bill D.

  8. #8
    Join Date
    Jul 2007
    Location
    Inkerman, Ontario, Canada
    Posts
    149
    I made one a few months back. Plywood, double funnel with steep sides for good flow, blast-gates at the bottom. and a glasstop for natural light. Works fine.

    5-SAM_4976.JPG 1-SAM_4972.JPG3-SAM_4974.JPG

  9. #9
    my first one was a ply but it quickly erodes from Rick O'Shea ing sand. I lined it with steel. Looks like Mark is running a pressure blaster there. Make sure you filter your material well I had some mesh filter sand went through every time. Have a restoration friend runs 3 compressors in a sound proof room at 200 PSI. Never a shortage of air in his case and nice you hear nothing other than the sandbalsting noise. He has a full size automotive spray booth set up for just that.
    Last edited by Warren Lake; 08-14-2018 at 6:57 PM.

  10. #10
    Join Date
    Feb 2010
    Location
    Pueblo, CO
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    237
    The one John Jordan made was exactly the one I made. Also a little more than 40 years ago. Used mine to etch some glassware for Christmas gifts.

  11. #11
    Join Date
    Feb 2008
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    E TN, near Knoxville
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    Quote Originally Posted by Dan Hulbert View Post
    The one John Jordan made was exactly the one I made. Also a little more than 40 years ago. Used mine to etch some glassware for Christmas gifts.
    You must have read the same magazine article I did! Popular Mechanics, perhaps?

    I still have mine and use it occasionally. I use it with silicon carbide grit from the auto parts store.

    JKJ

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