Homebrew PCBs

> I love it!  It's great seeing people from around the world use different
> techniques and material to achieve the same goal.  I nearly fell off my
> chair with the pic of the PCB hanging under the neon lamp.  :D
> 
It's just a 40W fluorescent lamp, just a cheap light for the storage
area (that's a wooden platform which divides the 4 meter ceiling into
  two 2-meter spaces).
I'm going to make an insolation bed, A4 size (it's the maximum size my
printer can print anyway), with a thick glass, 6mm maybe, to press the
transparency to the sens. board to elliminate the air in the middle,
which makes pictures fuzzy.

> I love your lab, it makes me realize just how badly I have to clean
up my
> workspace.  Ugh...
Actually my dad's lab, this is a TV repair shop actually. And I
cleaned up a little for the pictures ;)

> 
> Have you considered using a spray bottle to apply the
photo-purple-liquid?
> 

Yes but I doubt it would work, the liquid is very viscous. I forgot to
take a picture of it!.

> I would guess that US and Canada might not have access to all those
> materials.  Laws on cancerigenic (sp), toxic, radioactive  :D 
material are
> a bit severe here.  I wonder if equivalent materials could be
acquired from
> photodevelopment sources and such?  I heard of a product from Kodak that
> worked wonders, but I can never remember the name.

I don't think so, I heard you can get this kind of products in Spain,
and they have more severe laws for that in Europe. Anyway you could
try with Diazo-based inks, which are environmental-friendly. You
should go to a print shop, some place where they make small quantities
of T-Shirts with screen printing, they will most likely use this kind
of products.
> 
> I'm intrigued by your problem with even distribution of that
> photo-purple-liquid.  At first I thought of a centrifuge like the
folks in
> the Yahoo Casting group use to spin casts, but that would be messy and
> probably excessive force.  You just want to make sure that your
liquid flows
> evenly across the PCB.
> 

Yes, I read something about that, and it sounds very interesting. The
problem is to get a perfectly centered wheel to spin it at high-rev
and some way to attach the board to it. CD's are manufactured that
way. Of course, CDs are round and have a hole in the center which
makes things a lot easier :D

> Have you thought of a small press?  Sandwiching another layer over
the PCB,
> forcing the liquid flat.  Place a thin spacer and you have a controlled
> 'area' to pour in your liquid.  The same way as we make foundations for
> houses over here, a vertical mold, except your would be less than
1mm wide.
> 
> If your liquid is sticky, maybe you can use wax paper in your mold,
or cut
> out a panel from a teflon frying pan.  Wax paper will most likely
make 'wave
> patterns', a hard surface like teflow is better.

I think that would be something interesting to try. But the liquid is
W-A-Y sticky (it sticks to glass). The teflon pan would be interesting
but it would have to be some cast-aluminum  pan, to make sure it's
flat and stays that way. Problem with cast aluminum and real teflon is
price :) But as I say the liquid is viscous and takes a few hours to
dry, so the paint brush method is the best I could find so far. I'll
ask the manufacturer about what can be done. Maybe I'll be able to
dissolve the thick liquid, in order to get a thinner layer.
> 
> Very nice results considering how you went about to get them.
> 
Actually no, I severely blew that board. I also found out that my
transparency was bent a little and that caused a small out-of-focus
area. But the other picture I uploaded show a properly made board.
> Robert
> :)
> 
> 
> 
> -----Message d'origine-----
> De : Homebrew_PCBs@yahoogroups.com
[mailto:Homebrew_PCBs@yahoogroups.com] De
> la part de hjf2k2
> Envoyé : juillet 24 2005 17:18
> À : Homebrew_PCBs@yahoogroups.com
> Objet : [Homebrew_PCBs] Re: Experimental method
> 
> 
> Hey everyone. I posted the pictures as promised. Here they are:
> http://groups.yahoo.com/group/Homebrew_PCBs/files/PhotoEtching/
> 
> It's a RAR file with the pictures. Sadly the board came out
seriously bad,
> as it seems that I "underdeveloped" it, that is, didn't clean it out
> properly :(, but you can see that even in that case there are pretty
good
> results.
> 
> 
> 
> 
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> 
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