Homemade Shot/Grit Blasting Cabinet

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Introduction: Homemade Shot/Grit Blasting Cabinet

A cabinet for shotblasting small to medium sized components without the mess of open blasting, built entirely from stuff I had around the house and workshop.

Step 1: Introduction

I recently bought a small compressor with tools for my father's car workshop. I also got a shotblasting gun that that uses the venturi effect to draw grit from a bag and blasts it out with the aid of the compressed air.

While effective at removing rust and old paint, it is incredibly messy. I resorted to wearing a motorcycle helmet, balaclava, overalls, gloves and boot and would still find it the grit in my ears and inside my clothes after a blasting session. Also it went all over the workshop. With blasting cabinets costing more than the compressor did, I decided to build my own.

Step 2: Tools and Supplies

You will need:

a large plastic container,
I used a recycling bin which is now defunct as the council have just switched to wheelie bins.

some clear plastic,
perspex (plexiglass) will do, i actually used polystyrene as it was what i had lying around

some strong adhesive,
no more nails or similar is perfect

some wire mesh,
mine was from the grill of a truck, and old grill tray would work even better

2 small blocks of wood and some screws,
these are to hold the tray off the floor, virtually anything could be used

Tools:
jigsaw or fret saw
tenon saw
hacksaw
drill (hand or power) with bit big enough to get your jigsaw or fretsaw blade in
files for finishing
screwdriver

Step 3: The Method - Lid

1. Mark the window hole in the lid, leaving atleast an inch of room all the way round.

2. Drill a hole in the centre to get the blade in.

3. Cut out the hole using the jigsaw or fretsaw

4. Round off the edges with a file.

5. Cut a piece of clear plastic to size, atleast an inch bigger all round than the hole, with a jigsaw or tenon saw.

6. Glue the clear plastic to the underside of the lid with no more nails or similar adhesive and allow to set for 24 hours.

Step 4: The Method - Body

1. Cut the mesh to a size it will fit in the bottom of the tub, about 3 inches from the floor.

2. Cut two blocks of wood to a suitable size that they will support the mesh 3 inches off the floor, this is to hold the blasting piece out of the grit collecting on the floor.

3. Screw the mesh to the wooden blocks using wood screws and washers to form a solid base that stands freely in the bottom of the tub.

4. Using the drill and jig/fret saw as before, cut a hole approximately 4 inches in diametre in the centre of one side, reasonably near to the top. I suggest using a round object such as a grease tin to mark this out most easily. If you are unsure, start with a smaller hole, I have big hands and wear thick gloves so you might be able to get away with a smaller hole. The smaller the hole, the less grit will leak out. Round the edges of the hole with the file.

Step 5: Conclusion

Put your blast gun in the cabinet, put the grit and air hoses through the hole, clip the lid on and you are ready to go. The cabinet will need to be periodically emptied of grit, to do this simply take the lid off, take the grid out and pour the grit back in to its storage container.

I hope this has been of help to some of you, if you have any questions please feel free to ask in comments or message me with them. This is my first Instructable so constructive criticism will be gratefully received.

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    67 Comments

    Will the plastic window need to be replaced after a while because the sand or shot roughed up the inside surface?

    7 replies

    Not sure yet, professional versions use polycarbonate, i suspect for this exact reason. With the relatively low power blasting I'm doing the window should have a good life, and periodical polishing with a good paint cutter (have experience of doing this from perspex windscreen in car) should remove the damage and thus prolong the life.

    Save yourself the time and just go find some clear plastic film at an art, craft, or hobby store. I just did a google search for it and found 20 inch by 50 foot roll of .003" thick optically clear film for $15... Trust me: no matter what media you use, and no matter how careful you are, your screen is going to be wrecked in a hurry without a protective film. When the plastic film gets wrecked just tear it off and tape a new one on. As for the leakage, have you considered making the glove a permanent part of the cabinet? Just cut it enough to flare it out and tape it to the outside of the cabinet. Would help to have felt lined glove so your hands slide in and out easily even when they're sweaty. If you're using a dusty media (glass bead for example) you could improvise a dust collection system with a vacuum. You could even do it in reverse where you force clean air in (blow port on shop-vac) and just have an exhaust routed to a filter bag.

    A slightly cheaper way could just be to use some cling film, my dad uses it on the perspex window of his cabinet, you have to stretch it quite tightly to stop wrinkles, but it seems to work fine. @kington99 cool instructable :)

    thats a great idea....I.'ll try cling film on the window of my blast cabinet ?

    This is a little off the original topic but it sounds like this stuff would work great on motorcycle helmet face shields.

    What you do in this case for yes, the plastic will get pitted..but you can go to any major art store and buy clear graffix acetate sheets they sell to protect artwork and tape them over the window..when it gets pitted ,simply peel the sheet off and put another one on.This keeps you from having to replace the actual window itself.It seems I have gotten into a site that is overseas from me, but I like the forum and would like to share my knowledge.Here is A link to what I am talking about.These stores may not be available in your area, but the products will be at your local stores.Any art store has these.Available in rolls as well
    http://www.dickblick.com/products/grafix-clear-acetate-sheets/

    I use a professional cabinet to glass-bead the bushcrafting knives I make. to keep the lexan window from getting marred, I place a clear film over the inside of the lexan and replace it when it gets difficult to see inside. I guess you could use a couple of layers of clear packing tape the same way, just be careful not to point the blaster up.

    If you a filling a sealed plastic container with air it will very quickly over fill and start to bulge and potentially 'explode' showering the user and anyone nearby with grit! Very dangerous. You need to have some form of valve to let the air out but keep the grit in. On my version of this I have fitted a sponge filter which lets air out but keeps grit in.

    1 reply

    Yeah, it's not sealed, it has a four inch hole in the front for my hand as you can plainly see, also the lid is not airtight and more or less just rests in place, should you somehow manage to seal it entirely the disaster that would result is that the lid would lift very slightly, releasing the pressure.

    How about an improvement for this? Fix a large plastic funnel in the base of the box. The blasting medium could fall into the funnel and this in turn be collected in a pot. Obviously you'd need to have the cabinet raised up but this would eliminate the problem of the grit layer being too shallow to be reused straight out of the box.

    Good 'ible', well done.

    Kevan

    This looks great, way simpler than I thought possible. One thing I was wondering--what sandpaper grit do you finish your work to before blasting? I make knives and I'd like to try doing this in preparation for parkerizing. I just hate mirror-finishing metal.

    2 replies

    I don't, I use it for cleaning heavily dirty/corroded components off cars, I'm afraid i can't help you with your question.

    That's okay, thanks for responding. I still might do this when I get a chance.

    so how does the top not blow off or the sides buldge when you apply the air? is there a vent somewhere? I have a project im doing where i need to blast a few things but cant figure out how to make the cabinet.

    5 replies

    the lid is by no means airtight, nor is the fit around the glove, and the airflow rate I am using is not high, so it can easily leak away fast enough. A filtered vent might be a good idea if you're using a much larger compressor.

    id like to build somthing like this for temporary blasting of small parts. I need to run about 90psi for it to be effective. I wonder how you could vent this properly. Ive tried just using the gun in the open air and what a mess!!

    Here is a link that you can make a water filter system that works similar to A bong..You can hook up a common shop vac to it without the grit frying the motor..I found this today and going to modify mine tommorow with this system..I been running a shop vac with the filter bags they sell for them, but thats 10.00 for 3 of them..with this system, I won't have to buy the bags no more.
    http://www.chevytalk.org/fusionbb/showtopic.php?tid/197304/pid/1508054/
    Open the page and scroll down a little ..it is quite easy and cheap to do

    I am running similar pressure and about 8 cfm, to vent it cut a hole in the tub and cover it with a thick piece of foam, such as car air filter material. This will let the air out and keep the grit in.

    My dad has a sandblaster that he borrowed off a mate and he just uses a vairable speed vacuum cleaner to filter out the dust and keep it from exploding