Abrasive additives for ordinary pressure washers?

 I don't own a pressure washer, but I was thinking of buying one.
Probably gasoline powered, not intending to pay more than $1000.

Anyways, I was wondering if it's possible to set one of those units up
to do abrasive water blasting (to clean up some concrete surfaces).  I'm
wondering what extra do-dads are required (injector?  hopper? nozzle?
wand?).

I see that bicarbonate of soda is one option for the media (ie Arm &
Hammer Armex or similar) but that seems to have the potential to harm
grass, bushes, trees, etc.  I'm wondering what else can be typically
added as an abrasive media that requires no special precautions for
landscape protection.

 
The high pressure does the cleaning - you don't need additives.  The
liquid additives on the market are applied with low pressure as a
prewash but are only minimally more effective than plain water under
pressure.

KC

 KC wrote:


Then can you explain this item?

http://www.pressurewashersupplies.com/WetSandBlaster.htm

Seems it might make a medium-duty pressure washer more effective at
cleaning concrete or brick, maybe with a lot less water usage and no
chemicals (although I don't see why it should cost $200).

 
Never seen one before but as stated and shown with the small tip,
it's use is for spot treatment of paint/rust removal, not general
cleaning.

KC