DIY Soda Blast Gun

  1. Onoff Member

    Messages:
    1,324
    Location:
    Sevenoaks, UK
    Off down another rabbit hole.....

    Wanting to blast this aluminium mower gearbox I ran out of blasting media for my cheapo Lidl Parkside sandblaster. It's OK but you have to give it a shake now and then.

    Over on a mower forum one of the gurus there suggested home brew soda blasting and that I search out "pop bottle soda blaster" builds on YouTube.

    I tried at first putting soda crystals through the Parkside gun but it clogged/didn't work.

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    So...after a rummage in the garage and delve into the collected scrap and I came up with:

    - a cheapo blow gun
    - a copper tap connector, 15 down to 10mm
    - an airline connector
    - the plastic bottle the blasting grit came in from Lidl

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    I found if I unscrewed the end of the blow gun then an airline adapter screws in being the same thread.

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    I cut the tap connector down roughly at where it narrows down and found that slotted over pretty well, the airline connector.

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    I figured if I heated up the copper flare with the MAPP torch I could tap the airline connector into it.....and that's where it all went wrong! The copper bent like a banana!

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    Plan B!

    Another rummage came up with some heavy wall chrome steel tube.

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    The airline connector taps home nicely into the end of the steel tube. This junction mind is NOT airtight but we have a solution to that I think!

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    More later!
     
    a111r and Parm like this.
  2. Onoff Member

    Messages:
    1,324
    Location:
    Sevenoaks, UK
    So my lad 3D printed two plastic halves to clamp around the modified blow gun end/tube. The lid of the media container will sit upturned atop this with screws going through it. A liberal slug of CT1 sealant or instant gasket should ensure air tightness:

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    Parts printed:

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    All the bits ready for assembly:

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    I drilled a 6mm hole in the bottle cap and bolted it to one of the printed halves:

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    That allowed me to drill through the bottle cap:

    [​IMG]

    Then screwed it all together with some self tappers. (Just to point out that it's sometimes better to use nuts and bolts rather than wood / self tapping screws using PLA as the printed layers can delaminate under such stress).

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    I then drilled a 1/4" hole down into the barrel.

    Testing of the homebrew blast gun with crushed glass media.

    PPE consisted of bare chest, riggers boots, cut down jeans, a mask of dubious vintage and goggles. Oh, and welding gauntlets when I didn't need to hold the camera.

    It was suggested this might happen. One school said gravity would overcome the potential issue. Another predicted it to a tee.

    A little video:

    https://flic.kr/p/2j6yHjs

    FAIL!

    Seems all too familiar for some reason...

    The Lidl gun kept clogging. Haven't drained the air tank for a while thinking about it. Really should get an inline moisture trap.

    When the Lidl gun did work with the crushed glass then the blasting effect was, imo, outstanding:

    [​IMG]
     
    Seadog likes this.
  3. Onoff Member

    Messages:
    1,324
    Location:
    Sevenoaks, UK
    The home made blasting gun was a failure and the Lidl Parkside gun kept clogging. Off I went and spent £15 on one of these from eBay:

    [​IMG]

    https://www.ebay.co.uk/itm/MARKSMAN...324348&hash=item3d8a3920f8:g:In0AAOSwYP9c0CQi

    It comes with no instructions but as far as I can tell the black rubber hose pushes onto the ribbed connector on the blasting gun. The other end goes on the long pipe which you stick into the blasting media.

    I did all that, found an airline fitting and screwed that into the bottom of the gun. The metal tube I poked into the big bag of (dry)crushed glass media I got. I drained the compressor of any water.

    Started blasting and all was good, cleaning up a strut mount top off the wife's old Pug. Very soon though it was just air, not sand coming out. (Same as happened with the Lidl Parkside gun). The air too appears damp as it darkens the metal you're pointing it at. It doesn't darken it when you start off and it's blasting OK. My very uneducated guess is I need a "moisture trap" as aforementioned. Tbh I'm a bit of a compressor virgin. Always borrowed one if I've needed to use my nail guns. Spraying, I've only ever done from rattle cans. By a stroke of right place/right time luck I managed to score an Aldi Workzone 24L compressor for the princely sum of £29.95, new and delivered.

    https://www.aldi.co.uk/workzone-2-5hp-air-compressor/p/078920165026500

    Coupled it with some cheap air tools from Aldi & Lidl and tbh it's all good so far. (Yet to try the cheapo spray gun).

    I think what I need is as I say a moisture trap maybe combined with an "oiler". I have no experience of either. Been looking at something like this:

    [​IMG]

    https://www.ebay.co.uk/itm/1-4-BSP-...375798&hash=item3b3a1dfde0:g:wfoAAOSw8oJdlh0D

    Specification is: Max Pressure: 220 Psi - Oil Capacity: 130cc - Max Air Flow: 105 Cfm

    Compared to others on eBay it appears to have the two "glass" cylinders somewhat better protected by what looks like alloy housings. Some are all "glass" which I doubt would last very long with me!

    A question, using an oiler with a blasting gun seems a bit counter intuitive. Yes, it prolongs the tool life but surely it must deposit a film of oil on the workpiece that then needs degreasing?

    Any pointers to what's good/bad, what I should look for would be appreciated.

    Cheers
     
  4. Shedendman

    Shedendman Member

    Messages:
    4,359
    east sussex
    I was getting quite excited until the 3D printer part,like a lathe,if you haven't got one your screwed
     
  5. Onoff Member

    Messages:
    1,324
    Location:
    Sevenoaks, UK
    Seems I shouldn't have cut the top off of the grit bottle. It needs to have some pressure in there.
     
  6. Shedendman

    Shedendman Member

    Messages:
    4,359
    east sussex
    The Parkside gun,what compressor do you run it off,whats its requirements?
     
  7. Onoff Member

    Messages:
    1,324
    Location:
    Sevenoaks, UK
    This one as I said above:

    https://www.aldi.co.uk/workzone-2-5hp-air-compressor/p/078920165026500

    It starts off OK, as aforementioned, when the air is dry. It's not a tank capacity thing as I'm only blasting piddly little bits.

    Thinking to get a combined oiler/moisture trap but only use oil if I'm using a tool like the nail gun. Run the blaster just with the moisture trap.
     
    Shedendman likes this.
  8. Shedendman

    Shedendman Member

    Messages:
    4,359
    east sussex
    Like you i'm looking for one for those piddly little jobs to,but still scratching my chin over it
     
  9. brightspark

    brightspark Member

    Messages:
    30,770
    Location:
    yarm stockton on tees
    get a water separator and forget the oiler. there a waste of time and ruin the air hose just put 3 drops of oil; in before use
     
    Onoff likes this.
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