Homebrew PCBs

Hi guys,

Just to report, I have tried to scratch through the maplins PCB 
coating for circuit boards...should'a listened to that niggle in the 
back of my mind when I bought the spray...it's too rubbery:-(
The bit dragged and in some areas skipped over isolation tracks 
leaving resist or dragged part of the desired resist away:-(((
Oh well...overall, the circuit scratches look well formed, and once 
the board wiggle (yep, the drag on the bit caused the board to move 
instead).
Just need to find a coating that is etch resistant and which 
scratches easily and cleanly...metal blue stuff??
Might try uni's workshop department to see if they'll let me borrow 
some for free;-P 
I think a coupla gallons should do:-?

regards, PK