Plastic or plastic mix...Donny will definitly give you a heads up. I know the plastic works well (A) because it is the shape/configuration of the media that removes the scale/rust more efficently, unlike Black Beauty or Aluminum, which in order to be effective need high pressure/momentum thus creating more friction and heat. Downside of plastic is you need a "real deal compressor", like a two stage 5-10 HP at least to have the proper CFM to back it up. A single stage 3-5 HP 60-80 gallon compressor form Home Depot/Lowes will not get you there. (B) Plastic will cut your removal/cleaning way down v.s Alum./Glass/Black Beauty.
I have an Eastwood 100LB pressurized blaster I use with my 5HP compressor at home. By no means do i just have it hooked directly up to my compressor. I have 3/4" Class M copper running up the garage wall and all the way across at a 4 degree angle. Then into a leg/trap with drain and coming across with another 6 degree angle, then down into 1/2" downlegs to create a venturi effect. Split manifolds, one for lubricated air, one for dry air. There is a couple other traps/drains along the way. I have a desiccant dryer along with a good filter/regulator running out to the media blaster along with a disposable desiccant filter and another filter/regulator on the blaster. i spent quite some time studying Donny's threads, other peoples threads, and other internet resources before putting this system together. The main issues I seen was people buying small blasters, just pluging them into the undersized compressor's without the proper piping and filters/dryers and then wonder why they don't have the cfm to push media, or are constantly pluging up there blaster with water/moisture. The bottom line is a 5HP or less single stage will be working pretty hard to keep up with most blasters, thus condensing and creating a lot of vapor/water in your lines. Most companys that sell these smaller package blasters are pretty decieving saying, "low cfm, low pressure is all you need with your 3.5 HP compressor!" That simply is not the case. If you "plug and play" withouth the proper filters, piping system, and a substandard run of the mill compressor made for pumping up bike tires, you will have problems!
I use black beauty or aluminum a majority of the time with a 3MM nozzle but keep in mind that i'm primarily not blasing external sheetmetal. I don't think I would take the leap to try to blast a whole car. Would be way to expensive/time consuming and would make much more sense to farm out to the proffesionals like Donny. I do admit that it does work very well for smaller parts/areas and I am pretty happy with the unit thus far. Also, be prepared for a mess. You need a larger area to accomodate a blaster along with proper ventilation and personal protection. I will be blasting my own inner fenders area on my roadrunner project as well. And as far as soda, I agree with the other guys, at a do it yourselfer level, I would not do it. It's caustic, messy, and is not going to clean out those rusty/mudded areas worth a damn. Good luck, hope this helps.
