[sdiy] PCB Etching

[marmot1 at magma.ca]

Hello,
There was a thread on DIY PCB's recently - check the archives.
I regularly use the marker and etch resist transfer method for quick one-off PCB's. The most important thing is 
to first clean the copper surface using very fine damp scouring powder or cleanser applied with a rag. Use it 
to brighten up the surface - steel wool is not a good idea as it gouges the surface and makes the resist go on 
unevenly. Wash the board well and dry thoroughly before applying resist. I put the etch resist transfers on 
first - I only use them for IC footprints. Make sure they are rubbed on well - it helps to warm up the board 
over a hot stove element after to ensure the transfers stick well. Use a Staedtler Lumocolor marker (313, 317 
etc) for applying traces and pads afterwards. I use a plastic tray of room temperature ferric chloride etchant. 
Gently place the board copper side down on top of the etchant solution - it will float. Take care to avoid air 
bubbles. Etching takes 30 to 45  minutes depending on how fresh the etchant is. Remove board, rinse VERY well 
with warm water, dry. Remove resist with methanol or acetone on a paper towel. If needed, brighten up the 
copper again with scouring powder before drilling and soldering. Since changing from steel wool to scouring 
powder, I get consistently good etches with this crude but effective technique. Up to 23 chips per board so 
far. Take care with the etchant and solvents as they are corrosive and toxic - rubber gloves and glasses plus 
good ventilation.
Regards, Mike