Homebrew PCBs

In a message dated 2/11/2005 12:03:12 A.M. Central Standard Time,  
naveedguy2@... writes:

or is  there any other technique to transfer the PCB to the board.  Thanks.



If you have a Radio Shack (Tandy) store within reach, their  
pressure-sensitive circuit patterns are the best thing since Swiss  milk-chocolate!  With 
those, you can "rub-on" a PC pattern as fine as any  photographic method.  But it 
DOES mean only a ONE-TIME pattern, of  course.  You must first clean the 
copper with some household cleanser such  as Comet, etc., then rinse that 
SUPER-well, and dry, and I usually at least  "wipe" the surface with lacquer-thinner 
(acetone should do), and dry.   Then, apply the "rub-on".  then etch.  
 
It is best to WARM the ferric chloride solution to about 38-40°C.  It  will 
work much faster.  If hotter, it might loosen/remove the rub-on  stuff.  Not 
sure.  I'm too shy to try!  
 
Now the "professional" way to do PCB's is to make a 2x or 4x "artwork" and  
then make negative films with which you "contact-print" onto a photo-sensitized 
 etch-resist over the copper, but to do this successfully, one must have  
experience, and a professional PCB house to do the actual "printing" and  
etching.  Best, find a PCB house that will allow you to come over and gawk  and ask 
questions.  Many won't HEAR of such a nice accomodation to other  than a 
$250K/year customer, but some will treat young hobbiests with  civility.  TRY it!
 
Jan Rowland


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