Liquid paper used to PCB masking

I trying to used liquid paper for PCB masking, the result is not good. During PCB etching some line are slowly washout. You see in the image below.        

materials needed

PCB board

Liquid paper

Drill Bit

note: 

updated and edited june 2016

Old PCB used as guide to PCB drilling

PCB drilling 

CD-ROM mobot Project - Chassis testing

Chassis test run

tools needed for test are
AC-DC adjustable adaptor 3v -12V
Telephone wire

CD-ROM mobot Project chassis Third Wheel Assembly

Third wheel from cassette deck roller

tools needed

Pliers used to tighten the Screw
set Screw from for motherboard
Roller from cassette deck

CD-ROM mobot Project - Wheel assembly 2

Rubber wheel made from old unpaired sleeper

tools needed
knife used to cut the sleeper into round shape and paste into capstan