Homebrew PCBs

After seeing Stefan's results I had to try the silicone paper idea
myself. The silicone I used was GE Silicone I Clear Kitchen and Bath
which I bought at Lowes.

I did make a few changes to the process. First I used transparency
instead of paper so I could see what was going on. Also in an attempt
to get as even a coating as possible I taped down a few extra pieces
of tranparency for my putty knife to ride over to get an even
thickness. I also used transparency because I wanted to rinse down the
silicone to remove any residual acetic acid from the curing. I am not
sure what that may do to the drum or fuser.

My results were not as good as Stefan's. First the coating did not
come out as smooth as I would like to have seen it. It tended to have
some ripples and bubbles in it. When I ran it through my HP 1300 laser
printer I get a lot of toner dust scattered around. The image itself
looked okay. 

I then ran my silicone coated transparency through my laminator with
the circuit and most of my image transferred along with the toner
dust. The areas that did not transfer tend be in the areas where I had
ripples or bubbles. 

For me the biggest problem is all the toner particles that were
scattered around. I would not have been able to etch a board in that
condition.

Still I think the technique shows alot of promise. I probably will not
do anymore experiments today, but things I would try different is to
use a scotch tape spacer to try to get the coating thinner and also
try differnent spreading techniques to try to get the coating more
even. I also wonder if there is any kind of solvent to thin out the
thick silicone. That may allow for a more even coating.


--- In Homebrew_PCBs@yahoogroups.com, "Stefan Trethan"
<stefan_trethan@g...> wrote:
> Hi,
> 
> had to have a second try.
> relieved the pressure on the fuser rollers a bit, and made only one
run.
> 
> 
> 1000% the sharpest and best toner transfer i have EVER seen with NO
 
> soaking, just peeling of the paper!!!
> 
> Good, solid, scratch resistant transfer.
> 
> I might well have come across something here that will make my PCB
making  
> a lot easier.
> (Just think about it, no soaking, that means no rubbing an no
limitation  
> in minimum spacing because there is residue..)
> 
> Also, the transfer looks very, very sharp to me (must test further).
> Maybe the even surface of the silicone is better than rough paper.  
> (spreading is unknown, but the edges are sharp so it doesn't seem
much).
> 
> I'm glad i tried a second time. After the first one was so bad i
might  
> just have forgotten about it.
> 
> 
> Well, tests will follow, but i must do something else now.
> Pleas try yourself too.
> 
> 
> ST