Homebrew PCBs

I have an idea for developing double sided PCBs:  One of the sides 
are exposed first, then the exposed side is immediately sprayed with 
sodium carbonate solution with care so that it doesn't run off the 
edges of the PCB.  Wait for a while.  Then the Na2CO3 is wiped and 
this process is repeated until the paint on the exposed area comes 
off completely.  The other side is then exposed afterwards.

What do you think about this approach?

Mark