Homebrew PCBs

In a message dated 11/27/2006 5:34:09 A.M. Central Standard Time,  
lez.briddon@... writes:

Do  some other pens work better?



I have READ that German-made Städtler red works good as  lacquer paint, but I 
have NOT been able to find those locally.  
 
Sharpie black is all I have tried, and IF the copper has been  CLEANED with 
lacquer-thinner and dried with paper-towels, and NEVER touched,  that will 
"sorta work".  But the Sharpie ink was never intended as "etch  resist" so it is 
only "by accident" that it works at all.  I suspect phases  of the moon have to 
be JUST right for it to do at all.  I have NO idea how  the TEMPERATURE of 
the etchant affects the "life" of the Sharpie ink on the  copper, but I think 
SPEED in handling and clearly GREATER than usual care is  necessary for ANYthing 
good to happen with that!  The etch-resist pens  Radium Scat sold had a 
"thicker paint" but I haven't seen those in some time,  now.  No clue if they quit 
making those.  But they didn't have much  shelf-life at all!
 
Surely there is a reader of this group who has money to invest  who can open 
a little "PCB-Resist-Pen" factory and sell us EXCELLENT resist-pens  that will 
last for WEEKS, even if occasionally left OPEN overnight, for 69¢  each!   
Wot?        Jan  Rowland  


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