Homebrew PCBs

lcdpublishing wrote:

>Hi Alan, thanks for the reply.  I use a digital thermometer to 
>set/check the temp of the iron.  I have had great success at 380 
>degrees F so I always use that setting.  However, in the mess for 
>the last few days, I have tried anything from 240 degrees F all the 
>way up to 440 degrees F with about a 40-50 degree increment --- all 
>with the same results.
>
>Darn this is frustrating, especially when the last few boards I did 
>were outstanding.  Oh well, tomorrow is another day and perhaps the 
>moon and the sun will be in the proper alignment again so I can get 
>good toner transfer to copper again.
>
>Chris
>  
>


  Ok, with that said a few more things.  First, yes, I have some board 
that sticks relatively poorly.  It is brighter than normal, and seems to 
be staying bright, not sure if it's a coating or alloy of some sort.  
With dozens of sheets on hand I bypassed it and haven't really given it 
a second shot.  Note that if you even just took silicone spray, and 
sprayed on a board, it would be very difficult to remove, even with 
sandpaper etc, since it's inert.  It's why you do not ever ever ever use 
silicone products on a car unless you don't want to be able to repaint 
it, new paint will not stick properly and it's extremely difficult to 
remove.  Coatings and alloys etc that might work fine within the normal 
industrial PCB processes could conceivably make a board rather 
unsuitable for transfer or very difficult to use..

  Get some of the Reynold's parchment paper, it's pretty well non-stick 
itself.  You should get at least some to stay on the board with it, then 
you can look at the toner to board bond a lot better.  After heat and 
pressure, about the only thing left is the board itself.

  Actually the very best thing is to simply pre-etch the board.  Clean 
it some first, then etch until it turns the rosy pink, then rinse with 
distilled water.  The board surface should then be about as good as it 
will ever get, so then try the transfer.  If it won't work after that, 
no amount of other board prep is likely to work.

Alan