Abrasives for sandblasting

C

countershaft

Well-known member
Now that we have solved the sandblasting machine operation, suggestions for "what type of abrasives" to use. Remembering that crystalline silica is a dangerous material to breath. Good rust and paint removal qualities , cheap and dust free are all important factors to consider .
 
Aluminum oxide is pretty common for sand blasting, and should be readily available at most any welding shops, Tractor Supply, maybe even NAPA. Here is a good site to tell you a bit about some different types of media. We have used the Black Magic abrasive to remove industrial coatings on the inside of chemical storage tanks. It will take off damn near anything, in a hurry. But it does make a bit of black dust.

http://www.sand-blasters.net/index.asp? ... tegory=314
 
If you are doing it outside plain old mason's sand is cheap, a little dusty, cuts well. If you are using a cabinet type I prefer glass beads.
 
I use Kansas blowsand. A few years ago we were overhauling a GE steam turbine at our generating plant. The GE technicans ran out of boughten blasting sand. We went out and scooped up a pickup load of blow sand. They liked it much better than the boughten sand. They said if we would bag it , we could sell all we could get. If anyone wants a sample, I'll ship you some if you will pay the shipping Fred Mattal 67124
 
Bryson:

Not being a pro at this, my choice would be a fine sand if possible. That way there is no risk to my pond, or gardens or tires....

Maybe I am just among the un-initiated in this, but the idea of glass beads and such is a concern. Also, Em's cousin told me to be careful with what type of media to use.. he also uses fine sand. The only time he will use composites, man made media such as glass beads is in a sandblasting cabinet.

So I will choose the safer course until I learn more about it.. also, sand is far less expensive that say beads and until I become more adept, it is probably the wisest way to go, at least financially.
 
If you are using any form of sand, make sure you blast outside, as far away from any living spaces as you can get. Stand upwind of what you are blasting. Also use a good, well fitting respirator plus eye and ear protection. Silicosis, deafness or an injured eye are not fun.

Glass beads are made of silica sand, so all the same concerns apply.
 
I used to work for GE Power Systems, and in addition to building new units our shop brought in and repaired/reworked tens of GE steam turbines every year. Each refurbished unit would have to be blasted clean before being reworked, and then blasted clean before being returned, and it was always done outdoors with ground pecan shells.

At our other plant(s), gas turbine units were always bead blasted, and in addition to roughing the face of the airfoils to make them more efficient, it also performed the critical function of hardening the outer layer of metal to avoid erosion. High pressure steam can make even those exotic steel alloys look like microscopic swiss cheese after a while! Someone decided to save some money back in the early 90's and skip that step, and airfoils started falling off and "migrating downstream" during operation!
 
When we are working inside of factories, refurbishing or remodeling them, the painting crews always use corn cob media for blasting. I have not been able to find out much about it, or what type of equipment to use, but it does a hell of a good job, and the media is really light, so it is easy to handle. Last year we worked to retrofit the old GM Tonawanda Engine plant, where the 454 and 496 engines are produced, and they blasted all of the interior surfaces of the plant before re-painting everything. The corn cob media took off 70+years of grease and dirt and lead-based paint, like it was butter.
 
I've been using something called StarBlast from Dupont in my cabinet and outdoors for the big stuff. It strips through 50+ years of paint and grime like painting in reverse. I get it in 50 lb bags from a local blast product distributer.

Be careful, remember it's what you are removing (paint & other gunk) broken down into respirable size particles that tends to be most dangerous.

OK, Blast me! :-)

BlackJeep

Here's a link to StarBlast info http://www.titanium.dupont.com/NASApp/TTPORTAL/Mediator?action=4160
 
Question - can you recycle your blast media? I'm assuming different media are recyclable, albeit at different rates, the real point of my question is - how do you capture it and recondition it? In a cabinet is probably easy enough, but outside...

I'm picturing spreading out a big tarp across the ground and up at one end and trying to catch as much of the media as possible, then running it into a big funnel/screen to get most of the schmoo out of it, but that could be entirely fallacious.
 
Allen. The answer is yes. Just keep re-using it untill it's contaminated beyond your likeing! Or is turning into only dust (knowing you don't have a dust collector?) .....
 
Allen,

Although I have not tried it, I have given this topic some thought. My idea is to get an appropriate sized kiddie pool. Not the inflatible kind, but the semi-rigid plastic kind. Put a piece of plywood in the bottom and go for it. The containment should catch most of the reusable media. That's my theory and I'm stickin' to it.......... until it fails. :D
 
depending on what your blasting most of the silica, sand and beads leave a patina on the surface, On most items casting and such that could even be a good thing. but if you are blasting something where you want to minimize the degarding of the the surface as much as possible is where the ground corn cob and also walnut shells work nicely. I used walnut shells on some weber carb bodies that came out of desert storm that had some sort of military green coating on them and it worked great and had fewer problems than you would with sand. I did plug any orfices though just in case.
 
Countershaft,

You have to take in consideration what you are blasting too. The heavy castings can handle the sand, glass beads, and aluminum oxide.

But if you plan on blasting the sheet metal, I would recommend plastic blasting media.

The reason being is that the blasting medias like sand and such create heat and can peen the metal which causes warpage. Just something to think about...

Brian
 
DRacer,

I like your signature line! :)

Last week I opened a fortune cookie, and it said - "Phew! I thought I'd never get out of that cookie!"
 
Central Tractor Supply sells , alum oxide, black diamond and masons sand in 50# bags. $ 5.00, except for the alum . oxide Seems reasonable enough . I plan to spray "outside" and whether I recover the media or not , well we will see. It's the silica that you have to be carefull of , plus the paint and rust residue. Like Rudi suggests , I believe I'll try the mason's sand first .
 
I think I would try sandbox sand before mason's sand with the idea it flows better .... doesn't it? Mason sand seems like it would be too fine.

One more thing, if your concerned about "silicosis" ..... remember, sand is a major contributor to that. Protect/filter the air you breathe while blasting ...........
 
I learned the hard way about sheet metal warping when blasting. When i hired in as a apprentice mechanic at the outfit i'm still with, i had a old tool box i wanted to blast and repaint. We have a large (20x30) blasting room with grate floors and automatic grit reclaiming, recycling, etc... as you would expect in a large manufactering facility, complete with a pressurized air conditioned breathing hood. The media this machine uses is a heavy steel shot, looks like sand sized BB's, and can be slippery like marbels on smooth concrete. IT's heavy stuff. The blasting hose on this outfit is a 2" hose similar to a gasoline hose, the knozzle has a 1 1/4" hole, this thing means buisness. Well being the amature i was i suited up and rolled my tool box into the booth, locked it down and proceded to blast. It wiped the paint off that box like leaves off a driveway.... I blasted the box clean, shut down the machine and rolled it out. All seemed fine till i got a closer look at the box, it had bulged the front and sides, and made the door nearly impossible to open. It took me a good 2 hours with a hammer and mallet to straigten the box out enough to open, and another 2 to make it presentable. But man did that box look good when painted!!

So the moral of the story?? Heavy steel shot media and 18ga sheet metal don't mix well...

As for home blasting i use the medium grade sand from Lowes or Home Depot. I don't do much at home anymore, usually take it to work and use either the bead blaster or smaller grit blasters. Got permission to blast the whole cub in the large blaster this spring if i want too....but ain't got the guts...i doubt i could ever button up the cub enough to be safe in that rig.
 
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