Blasting defferent types of substrates

[Roderick Treece]

Does anyone know if it's ok or not to sandblast Glass , wood and HDU in the same blasting booth using the same media ?

Roderick

[Ron Berlier]

Hi Ther Rod,

If you recycle your blasting media you probably don't want to mix in wood or HDU particles into the same abrasive you use for glass.

R

[Patrick Mackle]

I agree with Ron. Not a good idea. (one day you may have a carved tempered glass panel blow up in front of you from rogue debris) I tried it early on in my business. I figured since I could blast glass, why not other materials. I got my first lesson while blasting glass. I had the clever idea that I could lay down blast resist, then use #44 spray glue to stick down paper laserjet prints of the design to hand cut. It wasn't long before I found the paper fibers were wrecking the sand flow and clogging my sifter screen.
The best way is to do several booths. Ones for specific material like glass. Others can be mixed as in used for brick, tile, and stone. Link them all to the same dust collector unless you can design or buy several collectors.
Besides as the material you blast is different, so is the grit size of the media you should blast with. Otherwise you will be wasting time and fuel/electricity.
Pat

[Ingrid Mager]

Roderick,
Pat covered most of it, but I would like to fill in with a few thoughts of mine:

With wood, it is GOOD to use sand for the blasting. What happens is that you are carving away so much wood so fast, in comparison to glass and the pulp can be difficult to remove from the medium. Evem when sifting everytime, eventually you end up with a pot full of very fine sawdust. I can't say for all pots, but with mine, when it is full of wood pulp, even though it is very fine, it now begins to clog up in the lines. So, it is practical just throw it out and add new sand in. By this time, your sand would have broken down quite a bit anyway. Also, you will probably being using more like about #30-#50 grit on wood, and this is almost alwasy too coarse for glass work, although there can be some exceptions to the rule, if you are working on certain textures, in which case one might even use slag. etc.
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Now, you DON"T really want sand in your glass blasting mixture as it pulverizes almost immediately, and now you have a booth full of fine and dangerous silica powder uneccesarily, and this powder won't cut a thing, and only creates a cloudy mess in the booth. That much said, Silica sand will actually cut glass rather nicely, and can be forgiving, and renders a slightly whiter cut, but it really isn't worth the hassle, not to mention working with dangerous media unecessarily.

With glass, the coarsest grit I have used that still rendered a fairly clean edge is a #70 AO for some very deep cuts. However, you are generally better off staying up in the 100+ zone, #100 being a good strating off point, unless you are wanting a silkier, slightly more translucent texture or are using photoresist. Don't be afraid to mix medias, in fact, different sizes of grit in your mixture can actually help. For instance, where yo need an overall medium grit to balst reasonably fast, ut you ahve some tiny detail in there as well, having a bit of real fine grit in your mix will get to those detailed areas that would otherwise be hard for the general mix to attack. Just don't put any sand in your good stuff...and of course, ALWAYS have the utmost in breathing protection if you are using any sand at all.
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With stone, you will probably want to use about #30-#50 AO for larger things and granite, and maybe #70 AO for smaller things. AS a rule, AO works better for this than SiC, which is actually the best for glass, but both will work. It has to do with the way it breaks down and attacks your substrate . SiC will lose its size, but maintain its sharpness. Garnet is also good for stone, as are grits like Stoneblast, etc....(Johnson Granite, Granite CIty Tool) Sand works, if you are doing it outdoors, but will break down, and requires VERY good breathng protection at all times. P-100 filter cartridges will work, (NOT the cartridges used for painting!!!!!) but supplied air is what you really need.
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If you accidently get coarser grit mixed in with your glass balsting media, you will end up with little bits that are small enough that you can't see them, but big enough that they will pierce your thinner mask mediums like Paint Mask, ruining your piece. I bring this up as I once had a coarse grit (#24-#60) blasting booth set up next to my glass blasting booth....the coarse grit leaked under the back wall....ran underneath the bottom plate, and continually contaminated the finer glass grit, even though I was sifting with a pretty fine steel mesh each time I filled the pot. (It needed to get totally resized, and not just sifted)
ARGH! I finally figured it out, but it was the pits (quite literally) until I did.

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Oh....you said HDU, but not stone.......oh well. I don't have HDU experience, but you got what I know about the others.

~Inga


If you don't do stone or wood often, a great way to go is to build what I call "Blast Cubes". You make a cubical frame out of PVC pipe and wrap it with with a clear, roll of visqueen. This makes for a great temporary booth that is easily moved around or broken down to store away when you don't have a lot of space. If you keep the PVC members at right about 50" long, or so, you will find that a simple 10' roll of visqueen wraps the tube very nicely. MIne is in storage right now, but I think I used 1 1/4" PVC....get it strong enough so the frame won't bend all over the place. You can use clamps to hold the visqueen together, or even a staple gun. Expect some leakage, but this can really be held to a minimal amount.

[Anthony Bennett]

Visqeen Booth,
Sounds like a good tip Inga, 50" square isnt that big, how do you introduce a sandblasting tube into the frame [;ease?
Also, I thought visqueen onlt came in black or blue, is there a clear version ?

[Ingrid Mager]

[quote="Anthony Bennett"]Visqeen Booth,
Sounds like a good tip Inga, 50" square isnt that big, how do you introduce a sandblasting tube into the frame [;ease?

I have just passed it through a corner, under some visqueen and then I go inside and blast away. Leakage is quite minimum, if you are a bit careful at all.

Remember, I said IF you don't do this very often. Naturally, you aren't going to have a nice easle, great lighting and all the bells and whistles, but often times, you really don't need all that, like if you are just doing a quick redwood sign. I used mine for granite plaques at my last place....didn't need great visibilty or anything.

Now, you can also set up a regular ol' tent (that has mesh windows in it) and blast inside it. Then you can put a fan outside one of the mesh windows, and have it blowing through the tent, out the other window, therby clearing some of the dust being created while blasting.
These are just makeshift options, but they DO work and can get the job done when you don't have a permanent booth, or need more than one booth but lack the space, or whatever.

Also, I thought visqueen onlt came in black or blue, is there a clear version ?

Absolutely. Also, I would also recommend the thicker mill instead of the thinner.These rolls are standard at most hardware stores, or at least in colder climates that I have lived in, where people often use the clear stuff to winterize their windows.