Best blasting media?

What's a good general purpose media for media blasting? Sand, Glass, Alum oxide? If you had to choose one for your cabinet which one?

 

Depends on what you are cleaning and how aggressive it needs to be. I do not like the look of an aluminum part that has been glass beaded so we use walnut shells. Those will not clean agressively enough if you are cleaning rusty steel. Baking soda works great for some things too but requires special equipment.


Different media and different equipment depending on what you need to do.

 

The Eastwood Company sells many types of more automotive-specific media (including walnut shells and some new poly plastic medias) in reasonably sized lots. They also carry all the various blasting accessories. On their web site they have a very handy application-specific media usage chart.

 

What do you want to blast ?
This is a bit off the topic , but if you want to clean and burnish Ferrari aluminium castings ? Then I have found wet blasting with glass media by far the best . You need a specific machine , but it's worth trying to find someone with one. Sorry the pic's are from my phone so not great , but you get the idea of what's possible
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You're not kidding! That engine is a thing of beauty.

 

I'm only going to have one cabinet so I'm looking for a middle of the road solution since I don't want to keep changing media. My guess is if I'm doing an aluminum piece it would be to prep it for paint so not too worried about the finish? Probably cleaning parts for welding or removing paint and some rust for painting and or repair.

My guess is I need to think about what I can use on the aluminum if I'm going to weld?

 

For your purpose fine glass beads are the way to go. It will affect the look of the castings though if you choose not to paint. Also remember, a cabinet is a cabinet. They all work about the same, the big difference in how well any will work is the dust collector and is also where most go cheap. By the best dust collector you can and do not use a shop vacuum as some claim you can.

 

All the media blasting I've even done was outside so let me sound stupid and ask what the dust collector does besides the obvious? can I just vent to outside for home use?

 

I only have experience using aluminum oxide and it is quite versitile for prepping for paint or removing rust. The one big drawback I see is that the part blasted comes out the color of the media and with a rough texture. From what I have seen online, the glass might prove better at leaving a more original texture on the material. As long as you are painting over the surface, aluminum oxide seems to do very well and is capable of removing gasket material, paint, and rust. Hope that helps.

Regarding the venting, the cabinet I use has a vacuum collector and works pretty well. As much as debris is flying around in there, I couldn't imagine being able to see in there without one. Also, a good light in there is a MUST!!!!

duck.co.za, Those results from the wet glass media combo look outstanding!!!

 

It'll be a big mess. I don't think you want the yard to look like a superfund site. Besides inside a cabinet, 2 seconds after you step on the pedal you will be blind from all the beads floating around. A cabinet NEEDS to be operated with a large vacuum connected to it.

 

I just bought a small scale cabinet--- Can be picked up and moved around, but big enough to fit a 16" wheel in. I have used corn cob media for soft/plastic parts and med. glass bead for metal parts. Both work well. I really need a bigger cpmpressor, but for a part here and there I can't justify spending the money on a bigger one. I can blast for about 10 minutes before having to let the tank build back up with air, which is fine for me....

Mine has a hole cut in it to plug a shop vac in for dust colection if need be, but found so far I don't need it.

 

....which coincidentally works well on brass shell casings.

 

I prefer glass. It will take you a little longer on the heavy gunk but gives you a little more control on the softer stuff. I don't like chrome, polished aluminum is OK, but raw aluminum is my favorite and glass bead does a good job on Aluminum... then I like to clean it with brake cleaner to remove any residue and top it with Eastwood's Diamond Clear for raw metal. Keeps it looking good and makes cleaning it a breeze down the road.

I have a new medium size clamshell cabinet, so much easier to use than one with doors. I saved my old table-top and use it for walnut shells to really spiff things up when needed.

Rick

 

Eastwood make an add-on to their cabinets that lets you use soda if you choose to. I have found mag wheel cleaner to work well on aluminum castings as opposed to blasting. Not quite as good but you could try it for ~$6 and see if it is good enough.

 

After many years of owning an industrial coatings business, I can tell you that trying to have only one media is like tying to work on your car with a crescent wrench. It can be done, but not well. Glass beads work great for cleaning some parts, but not for paint or powder coat prep. The beads tend to peen over the surface of the metal (as seen w/ a microscope), especially on softer metals like aluminum. If you use something like aluminum oxide or garnet, the surface will give you a better mechanical grip for your coating.
Rifledriver is right about walnut shells. They are great for cleaning cast aluminum.
If stripping/cleaning sheet metal, go slow, use reduced pressure, and hold the gun away from your part 8 to 12 inches. You can rapidly ruin sheet metal if you are not careful. Believe me, I know! Also very important to have clean, dry compressed air. You should treat your compressed air as you would your other utilities ( electric, water). DO NOT use PVC sprinkler pipe for compressed air. I prefer copper.
As with anything else, do it right the first time and you will be happy in the long run.

 

I am a machineshop/fabricator...

In the good old day, Chlorinated solvents(hard drive manufacturing facilities!), vapor shielded tanks, were the ONLY way to get ANYTHING clean in MY world...

Vapor degreasers are largely-as Rifleman states-become magnets for supefund status...if it works, we can't have it...in CA at any rate...but is is becoming the word everywhere...

I will disagree with Rifleman on glass media which is glass for ANY internally oiled engine, driveline components as NO MATTER how well you think you clean it out, some will remain behind-PERIOD.
I won't use it, NEVER.
EVER....
HOT soap and water, ultrasonics, kerosene and TIDE and water, LOTS of TIME AND EFFORT....soda seems to be the new *****in' deal, not enough EXPERIENCE to offer a meaningful opion. Walnuts are OK, but weak..
This is aproblem-material prearation...you MUST sweat out the liquyids which have wicked throughout the casting as well...this requires equipment, experience, AND TIME, lest you anneal the castings(aluminium)
CIAO!
and be careful...

 

I glass beaded a number of my engine parts and then sprayed them with high temp. clear paint (from a spray can).
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when you buy a cabinet - carefully choose the internal lighting system.
my harbor freight cabinet has a cra**y externally mounted light.

the shop vac route seems to work 'ok'

glass beads work for 90% of what i do...

rgds,
Vincenzo

 

I've been blasting parts for years and years and years.

I agree with the poster above who said it is very hard to get away with one type of media - he's totally correct. It's like wanting one weight of oil for all your cars/motorcycles/lawnmower, etc. You end up making compromises on all of them.

I have managed to get away with 3 medias for most of my work.

Aluminum oxide or garnet works well for steel parts or for parts with heavy corrosion that you need to clean up fast. I often clean up parts when working on my car - for example brake caliper mounting brackets and such.

Glass beads leave a very nice satin finish that is excellent for anodizing or polishing. I can take a part off the CNC machine, glass bead it, and it will anodize a matte finish and will look perfect. Or hit it with a buffing wheel and get it to near-chrome. It does peen the surface somewhat which is sub-optimal for adhering coatings like powdercoat.

Walnut is great for cleaning a part but it won't really remove any metal, and is a LOT slower than beads, and beads are a LOT slower than Al Oxide.

Bear in mind that you can vary your results by adjusting the pressure on the air too, allowing you to use beads aggressively or softly.

Also, they sell all of these media in different grit or screen sizes. If you do mostly aluminum and/or mostly small parts, a finer grade may be better (will be less aggressive).

If you want to start with something, start with small to mid-size glass beads.

My cabinet has a port on the bottom of the hopper which makes it pretty easy to change media, just be sure to clean it out GOOD. I drain it out, leave the drain port open then blow it out, then shop vac it out, then blow it out again until it's perfectly clean. Little stray bits of aluminum oxide can contaminate your batch of glass beads, for example.

As for the cabinet, before you use it, CAULK IT. If you don't make sure it's 100% sealed except for the extraction vent, it will dump media all over you and all over everything in the surrounding area.

You can use a shop vac for dust extraction. It's not ideal, but it will work fine, especially for occasional use. I wouldn't want to do it on an every day use blaster but it will work for occasional use. You want dust extraction because when the media hits the part it will remove material from the part (=dust) and some of the media will be destroyed too (=dust) and there will be powdery bits of media and general dust in your media over time which also means more dust when you blow it around. Without extraction, it will be difficult to see anything.

Also, make SURE you wear an appropriate dust mask while you are blasting - one that will filter out the size particles you are creating, and use it every time.

And never ever ever blast with sand. You can die from that. Nasty stuff.

I personally haven't had problems with residue on automotive parts. I anodize parts and they must be PERFECTLY clean or the anodization will not take in that area. Warm soapy bath with diswashing detergent and a good stiff brush works well. So do heated ultrasonic cleaners with appropriate solution, if you wanna get serious or are doing a lot of parts.

 

This would be going in my home shop and limited use. Probably get a small cabinet and farm out anything fancy or large or just take into the woods and blast away with sand. Mainly want to clean areas for welding or prep for powder coating.

Cracked castings are very hard to clean with wire brushes or grinders without removing a lot of metal. I need something that will get into irregular surfaces every once in a while.

 

Cracked castings , by all means blast them to clean the surface . But the crack itself should be opened up with a tungsten bur and high speed grinder , so you get proper penetration when you weld .

 

Soda blasting is the best. It washes out and any that does not is not as harmful. If you are welding the glass bead will imbed in the metal and will need to be ground and sanded out. You will need to grind into the crack far enough to allow full penetration. So not a big problem with the glass.

 

I guess I should have said broken and not cracked since there is no way to clean a crack(don't go there!). Sometimes you end up with a jigsaw piece that fits together really well and alignment is critical so I don't want to hog out the area to the point that there is no indexing to get the broken piece located. My soil here is all clay anyway so a little sand in the lawn won't hurt as long as I spread it out.
.

 

MY guy here is Brisbane in Oz does magic work. His own special formula.You judge. My 308 and 512 parts, unfortunately the BB stuff has to painted, to be original. You can see the difference between someone who SAYS they know what they are doing and someone who KNOWS what they are doing.
Cheers MG
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wow that's weird looking. so is that blasted with a special secret sauce then clear coated or what? Looks almost japanese fake plastic. makes me thing of the fake japancese plastic food you see in the window of a japanese restaurant.