Just a note to anyone that has a pressure washer and is just experimenting...
If you don't already, pick you up a GOOD rotary nozzle. They are pretty volatile when it comes to eating up stuff. I have one like so:
http://www.pressureparts.com/Pressure-Part-2640855.aspx
If you have paint peeling, you can get the rest of it off.
It would easily clean up to bare metal if you are just getting off caked up crud, etc. They are LOTS more effective than the standard nozzles.
Now, back to the blasting talk.
You might want to check this out as for the different blasting medias - there are a lot of sites out there like this:
http://www.kramerindustriesonline.co...ting-media.htm
http://www.kramerindustriesonline.co...tion-guide.htm
http://www.kramerindustriesonline.co...ison-chart.htm
DLB