How much media?

[Capt-Culver]

The concept behind media blasting has been fairly covered on this site. However, thru all my searches, I can't find anything regarding the amount of media required to completely blast a rolling shell? (+ door, fenders, hood and deck lid)

I don't have the indoor space large enough to blast inside. Therefore, I can't recover the media for re-use. I'll be blasting outside this spring and, after research, have decided to go with a walnut shell media, since it is bio-degradable. My question is, how much media will be required? I don't want to get half thru the task and then run out of media in the middle of the project. I have both the IR 185 and 350 compressors. I think we're going to use the 185.....the 350 seems like an overkill. We're guessing it's going to take about 1,000 lbs of walnut shell to do the job. But, that is simply a guess. So, what has been your expierence?

 

[Donny]

I probably run 8,000 lbs of media over a car shell, but, I recover it, can't afford not to. 1,000 is a bit on the light side, you will run out, especially since you're not recovering it for re-use. The reason this question never came up is because no one ever got that far in the weeks from what I have seen and read, and opined on.

 

[Capt-Culver]

Yowza!!! Thanks for the reply....Looks like I'll have to make room in the shop to blast in there so I can recover it. Thanks again!

 

[earlytime]

Donny what is the best media for doing the bottom of the car/ the dash frame and the rest of the car? Is there a media that work on all or would I have to get different media for each?? thanks Mike

 

[Donny]

There's a lot of variables that matter to answer your question. It all is based on your situation, your environment you have to work in, your tools (ie equipment), and if you're going to do this many times over. I specialize in Plastic, but, it is far more expensive to use than wider used medias like sand. Plastic isn't as good on rust as other more aggressive medias, so, for me I've mixed about 10% Alum Oxide into my Plastic, tried and used Walnut shells but they are way too dusty, and organic and can absorb moisture, good thing about Walnut shells is they cut good, and last forever! But, as I said way too dirty and dusty. If your doing it yourself and in your back yard, what compressor do you have? The key to doing any media blasting is air volume, you will need LOTS of it, your regular 60 gallon 5 hp compressor is too weak to run anything but fill up our tires. Good luck!

 

[earlytime]

Donny what media will work on the windshield and rear window channels and dash frame? also on much of the smaller parts. I understand about the compressor and it needs alot of air but looking for a good media that will work.

thanks mike

 

[Donny]

The thing to aim for is using the same media for it all. It's all time-based, and, the less time in the hood and suit = less misery. I like to work as quickly and efficiently as possible. I can't stop to change media when I hit the dashboard, then change back when I clean the window channels, so, if you're doing it as a one-time deal, not reclaiming it all, or reclaiming some of it, walnut shells are great, the smaller in size the better. A size of 20/40 is small enough to cut out the rust if you hold it there long enough. Don't buy media from H.F., get it from a supply house like S.O.T. http://www.sotabrasives.com/proofs/siteredesign/redesign.php You will get it way cheaper from a place like this. I think I asked this already, but, no reply from your end, do you have an appropriate size air compressor to handle this task, what about air respirator, and correct helmet? Do you see yet that Media Blasting isn't a back-yard task to be handled by the weekend DIY'er? To do it right, you are looking at investing about 50-60 thousand dollars, plus hard physical work. The key is finding ways to do it easier, faster, better and more efficient! On small parts, if I'm not blasting in my cabinet, I will try to tie them down to my table, or, just hold them, but, even with rubber blasting gloves, getting hit with that stream of media HURTS LIKE HELL, I raspberry'd my arm one summer b/c I didn't wear the proper gear. Again, good luck; pics?

 

[earlytime]

thanks Donny I think I'll take them in and get them done. No I don't have a big compresser. Thanks for the information

 

[YY1]

Just for reference, I blasted the drivers side front floorboard from the steering column to the first set of seat bolts over the weekend.
I removed the drain plug and put a cat litter pan under it, so i could reclaim some media.
I started with about 40# of garnet, and when that got low, added about 60# of playground sand (I know), each time my hopper emptied, I swept the enitre driver's side floor, the trans hump, and the pass seat.
I was able to reclaim about 40% of what was used per hopper load.
I didn't bother sweeping the pass until the last load, and got about another 30% on a hopper then. Some was trapped under the seat, and in the pass rear floorboard.
All in all, I put in about 120#, and went through about 5 hoppers with all the reclaiming.
When I was done I had about 1/2 a hopper or about 30# left.
So, even in a closed envirnment, I lost about 90# somewhere.
I'm sure I'll get more fom the pass side when I remove the seat, but I doubt 90#.

 

[Donny]

YY1, did you have fun? It is fun, to see the crud fly off is a good feeling indeed! But, I forgot how slow it is for most folks' backyard set up! It took a weekend to do from the steering column to the front seat bolts? Wow, that's slow! For reference, I do that section in about 10 minutes, but, then again this is my business, I'm surprised you lost so much media, I guess the air pressure was around 90psi? Post a pic or two.

 

[Meep-Meep]

Since this thread seems to be "everything you wanted to know about media but were afraid to ask" I think I'll stick my neck out and ask Donny the media man what would be the best type to use on a set of magnesium wheels. I have a guy that cleans my pump parts and he carefully tried plastic but stopped when he didn't like what it did to the surface. He did not destroy my gazillion dollar rim but did notice some very slight ruffing of the surface and stopped there. The wheels have some oxide buildup that almost looks like dirt and feels rough and can be scraped off with a plastic scraper or even a finger nail in some areas. I just thought there might be a very delicate procedure to clean the rims up by blasting.

 

[YY1]

I'd like to know that as well. I picked up an extra set of Dak R/T wheels and I'm thinking about painting them "body color". I did a spot about 4 inches with regular sand and it seemed to do OK.

No, it didn't take me all weekend. I'd guess about 2 hours, but I didn't really bust my *** at it, although I did work dilligently. That also includes removing the seat.

My setup kicks some moderate to good *** thanks to your reccomendations on compressor CFM!!

 

[Donny]

Magnesium wheels, humm, good question that I don't have the answer for! Recently, I did a complete set of 4 Cast Aluminum wheels that went straight to powder coating, here they are, before, after blasting, and after powder coating. Not too sure if you can see these up close...

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There is a media, called T5 Acrylic that is rather pricey, but, it's best on soft-metal wheels.

 

[Meep-Meep]

I'll find out what he used, but I'll tell you it's some white fairly sharp edged stuff. More research!

 

[BuckNeccid]

Gotta agree with Donny about how much this stuff hurts and can REALLY hurt you in the wrong situation. While with the RR we were using stainless steel shot blasting at about 125 psi with a basically unlimited air supply at that pressure. Using fire hose sized supply hoses, and a 1" diameter nozzle. I saw one man get hit with that shot from about 7 ft away, and it looked like he was hit with birdshot from a 12 ga. Literally had to go to the hospital to have it all removed. Another let it go into his hand from 1-2 INCHES, and some of it went in one side and out the other. He was in surgery within an hour. This can be VERY dangerous without the right equipment, and very uncomfortable WITH the right equipment. When you get that full suit on, the noise and limited vision can make you feel cut off from the entire world. It's really not as easy as it looks. Wanted to add, even with a 3 layer heavy canvas suit, I've been hit with the blast from another man beside me, and if you were ever whipped with a switch when you were a kid, you know what it felt like. If not, it STINGS bad, and will leave little red whelps wherever it hits. I dunno about a lighter media, but I'd say it will still get your attention. How about it Donny?

And even with 3/16th steel panels we were blasting, if you stayed in one area long enough, you could warp the devil outta the panels. Lighter sheet metal will warp with the heat, you HAVE to keep moving cause if you leave it in one place and don't move it around, you're gonna end up ruining some sheet metal. If it doesn't come right off, come back to it, keep that spot you're blasting moving around so you don't have a heat build up. A buddy of mine asked about blasting his hood off a 70 Charger, and the only local commercial blasting place uses Black Beauty, looks like tiny piece of coal. I warned him they would warp the hood if they tried it with that media. He had it done anyway, and then proudly displayed the hood to me when it was done. I looked at it from the side, and told him to do the same. He was seriously crestfallen when he saw how badly it was warped. The hood was no longer saveable and he had to get another.