Homebrew PCBs

I did run it through a second time with an unused bit of foil, and it still
did not stick 'perfectly'; same place, same pattern.  That's why I am
suspecting that the toner is the culprit.

Of course the folks at Electronics_101 told me about the LM3914 chip AFTER I
finished my circuit.  LOL  I was doing the same thing with diodes.  So now I
am changing my voltmeter design a 3rd time and going with the LM3914.  I
have yet to figure out how I can use it for an ammeter, but that's another
story.

I examined the copper close up today and there is slight pitting.  I can see
little dots where the sponge rubbed through the green foil, rubbed off the
toner and attacked the copper.  It is insignificant, tiny dots here and
there in filled areas.

I have yet to figure out why the edge of the PCB was so difficult to etch.
I had brushed that area as much as the center, and even longer.  Does copper
etch from the sides or from the top-down?  I just can't figure out why
unprotected copper was able to resist etchant.

I also used a plastic bin, I can't see myself just dabbing at the PCB
without a vessel; hybrid technique, Pulsar sponge technique with just a bit
more etchant and a container.  I had about an ounce of FeCL sloshing around
plus the FeCL stored in the sponge tip.  The edges of the PCB were often
dipped in the etchant and yet it made no difference.  It's like my PCB
etched from the center and worked outwards, in a circular pattern, kinda
like a portal to another dimension...

(...X Files theme...)

Robert
:)


-----Message d'origine-----
De : Homebrew_PCBs@yahoogroups.com [mailto:Homebrew_PCBs@yahoogroups.com] De
la part de bob_ledoux
Envoyé : juillet 25 2005 17:52
À : Homebrew_PCBs@...m
Objet : [Homebrew_PCBs] Re: Experimental method


The Pulsar Green Foil is great to allow sponging on the etchant--no tanks
needed.  If it doesn't stick properly the first time, run it through the
laminator again with an unused bit of foil over the bad area.  This works
for me.  



Be sure to visit the group home and check for new Links, Files, and Photos:
http://groups.yahoo.com/group/Homebrew_PCBs

If Files or Photos are running short of space, post them here:
http://groups.yahoo.com/group/Homebrew_PCBs_Archives/ 
Yahoo! Groups Links