Media Blasting 101

[SuperNovaSS]

Hey guys,


I know that many of you have media blasting cabinets and probably have a lot more experience than I do using them. I thought it would be fun to start a thread sharing our experience with the machine and types of medias and techniques we use. I'll start this post trying to explain the basic components of a typical blasting system along with the types of media I commonly use. I hope others will chime in with their experience so we can all learn something.

I have had my cabinet for about 6 years. Before that, I was paying a local blaster to clean my intake manifolds and other parts. His prices were reasonable but the drives back and forth across town and having to wait to get the call saying the parts were ready got a bit old. I found my cabinet at a car swapmeet and pulled the trigger not knowing a lot about them at the time. I ended up getting a pretty nice machine that I have modified over the years.

Below is a picture of my machine. These cabinets are pretty simple. The media gets poured into the blaster and is sucked up from the bottom to the gun, does its job, then drops back to the bottom again. The cycle continues....



The basic components are as follows:

Main door:

The main door/hatch allows you to get parts in and out of the cabinet. The door has a viewing glass that needs to be cleaned often and replaced periodically due to etching. Many cabinets also have side door(s)





Lamp:

On top of the cabinet is a lamp. Mine has 2 florecent lamps. Others use Halogen. Some cabinets also have side mounted lights.



Drain:

The drain is on the bottom of the cabinet. Many cabinets have a trap door style drain. That is what this cabinet used to have. I have upgraded with a metering valve that has an air bleed to allow you to adjust the amount of media being sucked into the machine. This helps control sputtering with different types of media.



Air Control:

This regulator allows you to control the pressure of the incoming air. Pressure is a very important variable.




Foot control:

Much like a gas pedal, this introduces the compressed air from the compressor into the system.



Gloves:

If you don't have these you will be a mess and your hands will hurt.



Blasting gun:

Um, this is the blasting gun




Vacuum:

All the debris being removed from the part along with media breaking down causes dust to form in the cabinet. This vacuum system removes and filters out dust. The exit from the cabinet is baffled to keep larger pieces of media from being sucked out.






Compressor:

You need to have a fairly strong compressor to keep up with the amount of air you use but can also take breaks to let the compressor catch up if you have a smaller compressor.



Water separator:

You probably have one of these already You don't want your media getting wet.



Stereo system or headphones:

This is the most important part of a blasting system. This keeps you from going insane listening to the vacuum fan and compression working their butts off, LOUDLY!




I think that covers the basic components of the blasting system.

For those who would like to see a video overview, click below:

http://vid179.photobucket.com/albums...psktza4vrs.mp4

Next I will show you the types of media I use most regularly.

Jason

[Billohio]

Nice write up. I have a bad boy blasting cabinet and it works ok. I have only used glass beads in it. I think the first batch were from Harbor Freight and didn't seem to last long. I did read someone on their website complaining that they beads they sell aren't beads and make more dust, wear out fast. So I got a box at a different place to try.
What media have people tried??

[SuperNovaSS]

The machine is only part of the system. The other part is the media itself. There are a ton of different medias out there. Sand is not one of them. Please do not use silica sand to blast, it will mess you up.

Not only are there a ton of different types of medias but within those types there are different sizes. This makes things very complicated when trying to decide what media will suit you best. I have been dealing with a company in Tacoma, WA called Tacoma Company and have found them to be very helpful. They will also sell very small quantities of media that will allow you to experiment without having a bunch of media left over that does not suit your applications. There is also a company here in the SF Bay area called Temple and Associates that is very good.

The 3 types of medias I use consistently are glass, plastic, and garnet.

I generally use these medias as follows:


Garnet:

This media is a garnet red/magenta color. It varies from a coarse to very fine powder. Garnet is a true abrasive which will etch glass, plastic, chrome, etc. I use this media to remove rust, staining, and to clean parts to "white metal". This is a fast working media on rust, etc.




Glass bead/Glass shards:

Glass is mostly used to polish. It is a slow working media that I use on metal part too delicate for garnet. I also use this to polish pieces that have gone through the garnet process and are "white metal". The glass bead at low pressure will give a as cast appearance to aluminum and steel that has been taken to white metal. Glass shards are what you see most of the time. They are usually referred to as glass beads. They are a bit more jagged that the beads. Glass beads are very uniform and consistant in size for a more uniform finish.



Plastic media:

This is my favorite media. When used at the right pressure, this media will clean parts without damaging the original finish. It can be used on chrome, plastic, cadmium plating and other fragile surfaces. Plastic is very good at removing paint and debris. Plastic is not technicaly an abrasive since it removes debris by impact.

There are 2 types of plastic media that I am aware of.

The first is Urea which is the standard media you will see. It is multicolored and likely made from ground up recycled materials. It works great and I use this one most of the time.





The second is synthetic plastic media. It is a uniform color and I believe it is purpose produced. This is supposed to be a more delicate material and is a bit more expensive.




As stated above, all the medias come in multiple sizes. I recommend experimenting with different medias and sizes, air pressures, and distance from the gun to the item to find what works best for you.


Jason

[SuperNovaSS]

Now I'd like to show you have this media works on different automotive parts. As many of you know, I see a lot of parts on Ebay. Most times I simply want to clean the debris off so the customer can see what the actual part looks like, not the dirt and debris. I also don't want to cause harm to the part or remove any important ink stamps or markings. This is where plastic comes into play. Plastic media removes dirt and debris without altering the original finish when used at the proper pressures. It is very good at removing paint as well as long as the paint is not too thick. Plastic, like most medias does not play well with grease, silicone, etc.

I am going to show you the use of plastic media on 4 items as shown. A 1969 Camaro Z/28 intake manifold that has been painted, a 69 Camaro Hurst shifter, a 11 inch Chevy bellhousing that has been painted, and a very dirty Holley double pumper carb.



Here is a video showing the part before:
http://vid179.photobucket.com/albums...psbou8wzyh.mp4

[SuperNovaSS]

Let's start with the intake. This intake was just removed from the blown up 302 engine I show in another thread. The intake looks pretty nice at a glance but it has been painted with aluminum paint. The plan is to use the plastic to remove the paint. Then we will see what the finish other the paint looks like and decide whether the intake needs to be refinished or left as is.





The first step is to remove the oil splash shield from the underside. This can be accomplished with a small hammer and thin chisel of flat blade screw driver. Persuade the blade under the rivet and twist. Repeat. Many guys say that the shield can be left on with plastic since it is just plastic but I like to take them off. It also reveals the date code and since I sell these parts, many guys want to know the date code.









Intake after:

Its hard to see in the pictures since the intake did not look bad or too dirty originally but the intake looks great after blasting. Unfortunately, the plastic does not remove the staining on the cooling ports or water neck area. it also does not remove from from steel fittings. Most customers want a as new looking piece but I am leaving this intake as it is since it would look great on an original car.







Here are 2 videos that may show the change in the intake better:


http://vid179.photobucket.com/albums...psm8zgtfex.mp4


http://vid179.photobucket.com/albums...psm8zgtfex.mp4

[SuperNovaSS]

Next up is the Hurst shifter. Again, it may be tough to see in the pictures but this shifter was very dirty. The stamped numbers and letters could barely be seen and there is a calcified layer covering all steel parts.








Let's get this thing in the cabinet:




A few minutes later:





Not too shabby! The debris is all gone and only the original plating and some surface corrosion remain. The plastic does not hard the rubber but does clean it.

Here are a couple more videos:

http://vid179.photobucket.com/albums...pseeiltook.mp4

http://vid179.photobucket.com/albums...pskawvoanq.mp4

[SuperNovaSS]

Next is the bellhousing. As I said earlier, plastic is excellent at removing paint. The outside of this bellhousing was completely blasted in 7 minutes.

Before:






After:






And a couple more videos:

[img]<a href="http://i179.photobucket.com/albums/...ba5vd.mp4" rel="nofollow" target="_blank">http://i179.photobucket.com/albums/...ba5vd.mp4[/img]</a>

[img]<a href="http://i179.photobucket.com/albums/...dhm0t.mp4" rel="nofollow" target="_blank">http://i179.photobucket.com/albums/...dhm0t.mp4[/img]</a>

[SuperNovaSS]

Finally, the Holley carb. Let me start by saying I did not realize how grimy this carb was when I pulled it off the shelf. I really don't know how a carb could get this nasty. Even the choke tower is covered in heavy grime. Isn't that supposed to be protected by the air cleaner?

For my own amusement and to show the limitations of the media, I decided to try blasting this carb as is. I forgot to snap any pictures of it after the initial blasting but the process can be seen in video below. I ended up having to remove much of the grease by hand so the media could actually do its job. I ended up blasting most of the grease off but not all since someone will be rebuilding this carb anyway.


Before:









And after:






And the videos:

http://vid179.photobucket.com/albums...pspsmzjxmb.mp4

http://vid179.photobucket.com/albums...pspughjwr3.mp4

[SuperNovaSS]

Finally, here are all 4 cleaned items:




.....and the video:

http://vid179.photobucket.com/albums...psazguyoxj.mp4


If you guys like these before and after shots, let me know and I can take pictures while using different medias to show what they can do.


Jason

[Xplantdad]

And...always make sure to turn on the vacuum when you are blasting...otherwise it's hard to see and the room gets filled with a fine dust cloud...right Shaun? [img]<<GRAEMLIN_URL>>/laugh.gif[/img] [img]<<GRAEMLIN_URL>>/shocked.gif[/img] [img]<<GRAEMLIN_URL>>/mad.gif[/img]