Sandblasting media

Jordan Baker · #1 08-07-09, 02:41

Hi everyone

I just picked up one of the big sandblasting cabinets from Princess Auto today as they were on sale. Anyway I not sure what kind of blasting media I should get.

I was told to stay away from the sand kind as it will wear out quicker since the cabinet contiuously resues the stuff.

Any suggestions??

Jordan

rob love · #2 08-07-09, 02:58

Personally I just use the sand I dig out of my back yard. I make sure it is dry, and sift it through some window screen. I prefill a couple garbage cans so I can make it through winter. The stuff works like a charm, costs nothing, and when it gets too fine it just gets sucked out of the vent.

For venting your cabinet, I would reccomend the princess auto dust collector. Toss out the filter bag mind you, and just shoot whatever it collects outside. They run about $120 and will keep the inside of your cabinet in a negative pressure state. This also prevents the dusts from sandblasting from escaping through the cracks in the cabinet. Duct tape also works well towards this....but put the tape on the outside of the cabinet. Inside will not be around too long.

I find that the gun will clog with various debris from the sandblasting. Things like chunks of rust etc. I plan to put another screen lower in the hopper to prevent the debris from getting to the pickup tube. While you can put your hand over the nozzle for a second and clear the debris, it just keeps coming back.

Also, be prepared to replace those gloves pretty quick. They tend to tear open fairly early in their life. The replacement gloves at princess are just fine.

Lastly, you may find small jolts of static jumping from your chest to the machine. It hurts like a bugger after a while. We get it here in the winter when it is especially dry, but it occurs on any dry day. For that I run a small wire to a sports wristband. The wire is attached to a snap which touches my arm. The other end of the cord is attached to the cabinet. Kind of evens out the electrostatic states.

Jordan Baker · #3 08-07-09, 05:46

Thanks for the info. I didn't know it needs an extra vent. Is it a must?

I will set it up tomorrow and try to give it a wirl on the weekend. I can't wait to try it out as I have never used a sandblaster before.

cantankrs · #4 08-07-09, 08:21

Quote:

Originally Posted by Jordan Baker

Thanks for the info. I didn't know it needs an extra vent. Is it a must?

Hi Jordan,

You've figured the air you're pumping in has to go somewhere. If you don't vent the cabinet by a powered means, after a very short while you can't see jack in there because only a fraction of the dust leaves with the exhaust air. Try it - if it's a problem go from there. Buying or building something to create some suction is probably necessary.

If you live in a high density housing area I'd reconsider ejecting silica dust into the air outside. If plenty of room then not such a problem. Just be sure it can't circulate back into your home or shed. I'm considering building a water sprayer unit to direct the exhaust thru so the particulates drop out of the airstream to form sediment. Depends entirely on your surroundings.

Some people use silica sand and bugger the consequences, others pay good money for Garnet which I've been told is not toxic. You can buy glass beads from a blasting media distributor, and even crushed wallnut shells, possibly plastic blasting beads, etc, etc.

Glass beads probably good idea for aluminium items.

Have FUN!

Alex

Alex Blair (RIP) · #5 08-07-09, 13:43

Quote:

Originally Posted by Jordan Baker

Hi everyone

I just picked up one of the big sandblasting cabinets from Princess Auto today as they were on sale. Anyway I not sure what kind of blasting media I should get.

I was told to stay away from the sand kind as it will wear out quicker since the cabinet contiuously resues the stuff.

Any suggestions??

Jordan

Jordan
Before any sand blasting ,cut some clear light Plexiglas windows over the inside of your permanent viewing window..Duct tape tightly around the edges so dust won't get between the two glasses..(At least some heavy clear flexible plastic sheeting)
Then you are ready to sand blast..You do this to protect the permanent window clarity..
When sand blasting you will inevitably point the blasting nozzle at the window..when you are all liquored up or asleep..That will instantly give you a nicely "Frosted" window that you can't see dick through..
And the ordering and installing of an expensive window..
Do it before you start and save your self a lot of annoyance down the line..
Guaranteed you will replace it twice a year if you are careful..

Jordan Baker · #6 08-07-09, 14:43

Thanks again for the help. I'll look into the venting aspect today.

The mediums that they had were
crushed glass (#50) 20-35
aluminum oxide (80 grit) out of stock
crushed walnut shells
and some kind of slag, cant remember the name

Adame · #7 08-07-09, 16:42

Hi Jordan

I bought a soda blaster. In Milton. It uses baking soda and is enviormentally friendly. (rain washes it away).

It removes paint grease etc. But doesn't damage metal etc.

Cheers
Adam

REL · #8 08-07-09, 18:20

Wear a good HEPA mask when you're using it. I speak from experience. Silicosis is not fun. Glass beads...last I heard glass is silica and silica is glass, as they are used the beads break down into shards which work even better than beads due to their sharp, irregular shapes, until they break down to the point where they are too small and light to work. Glass dust is glass dust. You don't want to breathe it.

Even if you use steel shot or some other media that does not break down, there are all kinds of interesting bacteria, fungi etc. living on old rusty objects. You don't want to inhale them. Your lungs are a nice warm, wet dark place, where such things like to grow if they can. Of course some people can tolerate more than others.

Those old paints were mighty toxic sometimes too.

Fresh air supply to your mask with a remote hose is best if you can be sure of an inlet location for your hose that won't be contaminated by blown dust etc. from the dust/media collector's outlet. That's what the professionals use.

Soda is excellent for soft metals like brass and aluminum or thin steel which peens and warps with sand, and sometimes even with glass beads. Too bad the media is so expensive.

Poor man's sandblaster is a siphon feed for a pressure washer. Keeps the dust down, but best done on a very hot day.

George McKenzie · #9 08-07-09, 19:36

I made a blasting cabinet for $300 . Check it out in Army Motors #125 . This is the best one I have ever seen . It is made out of an old truck sleeper . I put a hopper under it and it is on small wheels can be moved easily out of your way or shared with another person . I use my shop vac with a long hose so it is outside ,because of the noise. There is a fine screen that catches most of the dirt and paint that I vacume up ,and when it is too bad I can open the bottom and reclean the blasting material . I use glass beads (4) bags . This will do things 7 ft long .You can get plastic window cover to cover your window to stop it from getting blasted up from Princes Auto .We have done wheels ,heads, fenders ,doors .ect. The old truck sleepers can be bought for $20 and the only thing you have to do is make two holes for the hand gloves .put a plastic window over the hole that the driver used to get into it , a screen on the bottom and some lights .I might add that if you sodablast be sure you clean off the soda as it will cause rusting when it gets wet and forms an asid .If any one needs more info EM me

rob love · #10 08-07-09, 20:45

With regard to the window getting sandblasted, I have gone to a different solution. I just let it get blasted. The plastic frostshields to protect it run about $3 each, and get sand etched rather quickly. Instead, I just replace the glass every few months. Princess used to have them for just $8 each. I had a small stack of them, although I also notice that princess seems to have quit stocking the replacement glass.

WRT the air exhaust, there are actually two ports on the cabinet. The one on the left would be for fresh air intake, while the one at the back of the cabinet will be for exhaust. I used to use a modified fan for the exhausting, but the dust was destroying the fan annually. Without the negative air pressure, you will not see anything.

WRT all the various environmentally friendly and health conscious blast media, the problem with any of it is that the end result of blasting adds things like the lead based paint, rust, possible asbestos, and whatever else is present on the item being sandblasted. So in the end, anything used must be considered toxic. Maybe just less toxic. With a good vent fan on your cabinet, you will have no need for masks or supplied breathing air. The cabinet will be in a state of negative pressure, so nothing will escape it.

cletrac (RIP) · #11 08-07-09, 21:04

When it comes to protecting a vision port the best thing I've found is a piece os Saran Wrap or the like. The sand bounces off without making a mark.
I agree with Rob on the media bit. Sand is cheap and you don't want to breathe the dust off any of it. This thread http://www.class-five.com/~mlu/forum...t=sandblasting
shows the cabinet I made.

George McKenzie · #12 09-07-09, 07:18

When I am beadblasting I could do it with a white shirt and tie There is no dust what so ever .The only time I use a mask is when I put things in or out . My window is 18"x30" and is plastic so I cover it with the Princess Auto material and I didn't think it was very expensive and will do quit a bit of blasting before I have to change it .

Jordan Baker · #13 16-07-09, 06:25

OK so I got the cabinet all setup today and finished assembling it. I used a silicone adhesive to seal all the panels but still found a few spots that I missed. As for the media I chose. I just went with the glass/sand for now.

My next problem is the compressor. The little one we have just wont cut it and I fear that I will wear it out rather quickly. I was going to check out Home Depot tomorrow to see what they had. Any suggestions.

Lynn Eades · #14 16-07-09, 09:37

The air consumption depends on the type of gun and the jet in it.
Compressors are rated by the FAD (free air delivery) in cu. feet per minute.
It's hard to get apples for apples, but go for the biggest one you can afford.
A large receiver (tank) will let you blast longer before the pressure drops off, but it also means that you have to wait longer to pump up again, if the pump is to small.
Keeping the media (sand) dry is very important to having it flow freely, and work well.
LASTLY, but MOST IMPORTANT. A young fella like you needs to be very careful when it comes to dust, and when blasting it is hard to avoid breathing at least some of it, sometimes. Because of this I would seriously reccommend using a media that is NOT silica based. Silicosis leads to lung cancer. Buy some garnet or other suitable media, and a respirator. They're cheap compared to maybe cutting 20 years off your life.

rob love · #15 16-07-09, 15:17

I am not even sure you will find a compressor big enough at home depot. Seems like what they call a 5 hp has a motor about the size of a household clothes dryer, and the results to match. I drilled out the passage in my sandblast gun to allow more flow mind you, and get the results of a commercial sandblaster out of it.

As to air supply; I have an older 2 hp (with one of those massive old style 70 pound electric motors) and will run one of those wheelbarrow type gas compressors in tandem with it when I sandblast. I am using one of the princess auto made gas powered compressors, somewhere around the 9 horsepower range. It will also keep up enough air to use a commercial spray gun. Once I get electricity into my new shop, I will hook up my 2 stage 7-1/2 horsepower compressor, which I got from a auto dealership closeout.

I will echo Lynn's recommendation to avoid that dust. I'll snap a photo of my exhaust system when I get out to the shop later. It is the best $120 you will spend, as it removes all dust from the cabinet, dumping it outside.

Bob Carriere · #16 28-07-09, 22:11

Oure expereince at the barn has been with the Princess cabinet..... which once assembled needs to be glued shut and/or taped.

I choose at the outset to use aluminum oxide.....expensive but lasts a long time and cuts fast. Sandblasting cabinet is USELESS unless you hookup a shop vac to create a neg. pressure....... I use a 5 gal. metal can to catch osme of the heavier dust before it enters the shop vac...... buy a shop vac with a written 5 year wrranty and expect to replace every year...... no matter what you do the aluminum oxide will kill the blower/motor bearings.

On a regular basis dump the blasign media as it gets full of large flakes that will plug the suction tube....... nozzles also need to be replaced as the wear to a large orifice and reduce your cutting capacity.

On the glass...... I made a new wooden frame held by wooden screews which are easier to remove to replace the plastic lining. Have a set of spare rubber gloves.... you will cut them or wear holes in them at themost unopportune time..... like late on a weekend and Princess is closed....

Keeping a good source of lights inside is also a challenge.... I have taken to junking them regularly when they get tooooo pitted to let light out....I have opted for under the counter lights from Home depot that runs on 12 volts....cheap and easy to replace.

Finally the "kompressor"....... like other manly things bigger is better.

Check out the specified C.F.M. of the cabinet as listed in the Princess catalogue...... you do not need high pressure but high volume.... youmight get by with a high CFM 7 1/2 HP..... as large a tank as you can find for the reasons given above...... you do not necessarily need a two stage compressor....... but they do come in handy to run a 3/4 inch impact for those stubborn rims studs...... requires 125/150 psi..... 900 pounds of torque and we still need touse the hot wrench to mellow the nuts to some mobility..

I am using a 10HP Princess running on single phase 60 amps on start up..... when it kicks in the lights dim in the village..... 120 gal. tank rated at 33 CFM at 100 psi.....

Caution..... whatever size you buy..... install it as far away as you can... they are noisy...... I had no previous expereince and installed mine in the attic of the barn...... never regretted the efforts to get it up there..... if you are in attic looking for parts and the sucker goes on...... hope your head is not under a low part of the ceiling.......they are as noisy as a Harley Dee.

Be prepared to drain the water out of the tank regularly.... so make provision for easy access to the drain plug/valve...... a good 3/4 in. ball valve from Princess will do the trick.... and a hose section to shoot the water in a desireable direction....... one litre of water at a time coming out at 150 psi really fogs up quickly......including oil from the compressor....

One final note..... when you pipe in your air lines from a remote location to your work site....... consider installing a special flexible section to you 1 inch steel delivery line..... it will reduce noise and vibration to the steel line.... and use a water trap in addition to draining the tank.

Now you are set for a blow job.....

my 5 cents worth

BooBee

Jordan Baker · #17 28-07-09, 23:03

Hi BooBee

Thanks for the info. I picked up 2 bags of the sand/crushed glass to start with. When I built the cabinet I applied silicone adheasive along all the joints. I found a few places I missed once I got started but overall its reasonably leak free. The only big leak is around the bottom edge of the door. That plastic seems to have a slight warp to it. I may jsut have to make it out of steel plate then.

So far I'm not using any lights, just shining a light from above me. And I don't have any suction hooked up yet. i find it works out fine so far. Ive got no dust that gets out when im spraying and with such a small compressor I can only spray for a min then wait for it to catch up. My uncle maybe getting a big compressor via work. He said its got a huge tank so we will see.

Snowy · #18 29-07-09, 04:42

Quote:

Originally Posted by rob love

WRT the air exhaust, there are actually two ports on the cabinet. The one on the left would be for fresh air intake, while the one at the back of the cabinet will be for exhaust. I used to use a modified fan for the exhausting, but the dust was destroying the fan annually. Without the negative air pressure, you will not see anything.

I'm working on improving my el-cheapo sandblasting cabinet at the moment and am thinking that an extraction fan could benefit from a cyclonic seperator as well as a fine particle filter. Some vacuum cleaners use this method and they seem simple enough to make after seeing this article on Hack-a-Day a few days ago: http://hackaday.com/2009/07/19/cyclo...st-seperation/
Principle of operation: http://en.wikipedia.org/wiki/Cyclonic_separation

Steve.

Pedr · #19 29-07-09, 19:32

Thanks Snowy,

That's really answered all my questions. This is going to be the answer to my problems. Have killed a couple of vac's already and hate having to empty and clean dust extraction system every hour.

Spoke to my ol' man ( who's a mechanical engineer specialising in designing and building special purpose machinery ) asked about using a cyclone to remove glass bead dust from my cabinet to allow reuse of media after cleaning, He said that it wouldn't be possible because material is usually blown into a cyclone ( he's been working in the mining and paper pulp industries, the first where they blow air down the drill hole to reclaim the drill castings collected at the cyclone and the second where the waste passes through the fan which allows it to be smashed into smaller pieces then blows it into the cyclone and onto a compactor bin for recycling through the pulp mill again. ) Anyway, this proves that what I was thinking about will infact work.

I like the features of the Clear Vu CV06, in that it has the sprial ramp on the dust intake, but I love the thought and design that has gone into the Oneida Dust Deputy, especially the larger unit, but the cost makes them a little prohibative and that they haven't been used on blasting media only saw dusts. After watching all of the Youtube video presentations of these cyclonic separator systems, I think that ALL vacuums should have one of these.

So, once again, thanks to Snowy for this tip.

Pedr

cantankrs · #20 30-07-09, 11:48

Hi All,

Seeing Snowy and Pedr's posts forces me to finally stop and mention Bill Pentz's hard working efforts to help guys like us save our lungs. http://billpentz.com/woodworking/Cyclone/index.cfm
I'm pretty sure he has details on how to build your own cyclone as big as you need and with the blower on the top so only 'fines' travel thru the blower.
I haven't tried building one yet but its on my list of things to do before I need it so I won't die early.

If you use his info then he sounds like a bloke worthy of a donation.
And I'm not related to the chap in any way.

Regards

Alex

Bob Carriere · #21 31-07-09, 19:59

I have installed a 5 gallon metal can with a store bought plastic cover that has a molded angled intake and outlet, which they claim, will spinf the air flow....... it collects a lot of solids...... inclusing a lot of the blasting media(aluminum oxide)........... media is so dusty fine that we discard as resuing it would just be a waste......It has prolongued the life of the shop vac to at least twice as long as before...(over a year now).... and the negative pressure of the cabinet keeps leaks to a minimum so a face mask is hardly required.

In answer to Jordan's door leaks....... get yourself a roll of winter foam rubber door sealer at CTC...... get the thin type 1/8 or 1/4 soft foam.... easily installed witht eh self adhesive backing......

I find that turning off the ceiling lamps in the shop reduces glare from the window glass and increases visibility to the inside.

To save our backs and make moving the cabinet easier we built a angle iron floor platform on casters.... raises the hand holes about 6 inches and provides a shelf for the shop vac and 5 gal. can all in one contained unit...

May actually use it this weekend to clean up a doz. or so rear shock steering ball linkages from earlier CMP......now that I bought replacement gloves....

Bob C.

George McKenzie · #22 04-08-09, 06:55

This is what my truck sleeper look's like .No dust ,no leaks .Very portable .My 27 cu ft doesn't run half the time . I use my shop vac with a long hose so I can put it outside the shop so it is quiet .and if there is dust comming out of the vac it doesn't matter as the vac is outside .

maple_leaf_eh · #23 10-08-09, 03:58

Are you sure you didn't steal that from some hospital nursery ward?

The gun community rarely sandblasts any gun parts, but they do need to vibrate and clean cartridge cases. The standard media include walnut shell pieces, corn cob pieces, apricot pit pieces and white rice. The latter surprised me, but anything that is hard surfaced and slightly textured seems to be required. Somebody lately found a supplier of hard plastic beads at his wife's craft supply store. He claims they work like a charm. I don't know how any of this is going to flow through a nozzle, but it is the thought that counts.

Cleaning regimes for cartridge case tumblers usually include some form of chemical rejuvinator and household dryer softener sheets. The mesh turns filthy and the media gets cleaner.

George McKenzie · #24 10-08-09, 04:22

When I was looking for a box to make this I stumbled into this sleeper and I can tell you there isn't one on the market that will work as good as this one.The total price was $300 which makes it even better. I can change the beads to other material by opening the bottom to clean it out .Very pleased with the results.

hrpearce · #25 25-08-09, 22:40

A couple of weeks ago my neighbour with the Dodge bought a sand blasting cabnet and complained he couldn't see into it. I printed this thread for him and he bought an extraction fan. KP always buyes the best he bought a dust extractor that collects the heavy particles for reuse. He thanks MLU for the help.

Lionelgee · #26 30-08-09, 05:20

Quote:

Originally Posted by hrpearce

A couple of weeks ago my neighbour with the Dodge bought a sand blasting cabnet and complained he couldn't see into it. I printed this thread for him and he bought an extraction fan. KP always buyes the best he bought a dust extractor that collects the heavy particles for reuse. He thanks MLU for the help.

G'day Robert,

Could you please identify if the extract was one of the ones mentioned in this thread? Also what the make of the extractor was; where it was bought from and what it would have cost?

Also, more importantly is he going lend it to you every now and then?

Thanks

Kind Regards
Lionel

hrpearce · #27 30-08-09, 13:11

Hi Lionel,
It is a dust extractor fan designed to collect sawdust off docking saws. It was bought from Total Tools in Wagga and was around the $500 mark. I don't know the make but I can check next time I drive past and KP is home. I don't need to borrow it as I just use creek sand and blast in the paddock and the wind clears the dust.