[hackerspaces] Instructable: Super easy PCB production with vinyl masks

[B F]

No intention to be vicious, but here's my comments:

You say:
"WHAT YOU NEED:
"- Prepared vinyl mask (if you don't have a vinyl cutter - sign shops
and many hackerspaces do!)
"- Etchant solution and glass or plastic tray
"- Fingernail Polish remover and acetone safe container
<snip>
"We will skim over how to design and cut the pcb design into vinyl and
at this point assume that you have a cutter or know someone with
access to one (local hackerspace or even a local sign shop!)
"It's the same as making any vinyl cut sticker.
"See the additional pictures in this intro for some educational
pictures of the preparation of a vinyl sticker in this step."

Comment 1.  That was a pretty big skim for me.  Can  you at least
point out some on-line information about such masks?  That's outside
my experience.

You continue:
"STEP TWO - ETCHING THE PCB
"FOLLOW ALL INSTRUCTIONS AND WARNINGS THAT APPLY TO YOUR PCB ETCHANT!
"This step is the same with any method of DIY PCB etching!
"CAUTION!   Regardless of how you make your mask - this is NASTY stuff
if you are sloppy or careless.
"again:
"FOLLOW ALL INSTRUCTIONS AND WARNING THAT APPLY TO YOUR PCB ETCHANT!
"Use gloves (stains and chemicals)
"Etch in ventilated area (fumes)
"Don't be CARELESS or SLOPPY (this can be serious stuff!)"

Comment 2.  What exactly are you using as etchant?  Ferric chloride is
the stuff I know.  Granted, I wouldn't want to eat the stuff or swim
in it, and it may be somewhat acidic and prone to giving off a bit of
hydrogen chloride vapor, but really it's not all that bad as chemicals
go.  Are you using something else?  It's actually more toxic AFTER
being used, in that it then contains copper, which is somewhat toxic,
whereas ferric (iron) is much less so, if at all.

You continue:
"Here's the last trick -
"Take some standard acetone based fingernail polish remover and soak
the board for a minute or two.
"The adhesive on the vinyl softens and the vinyl just slides into a
nice bundle of synthetic 'seaweed' to be scooped up."

Comment 3.  I can see this working, but I can see it NOT working too.
The problem is that "standard acetone based fingernail polish remover"
doesn't exist.  Even if you specify a brand and product number, there
is nothing to prevent the manufacturer from changing the formulation.
The active solvent in nail polish remover is, in my experience, either
acetone or ethyl acetate, and either may be diluted with water or
possibly alcohols, laced with perfume or even oils or lanolin.
Different formulations MAY work, but then again they may not.  And
perfumes and oils are not particularly desirable residues on a PC
board.
It would be much better to specify exactly what was needed for this
step.  Acetone can be bought as such at any hardware or paint store.
If it needs to be diluted before use, candidate solvents include
water, denatured alcohol, 91% isopropyl alcohol (from a drug store),
and others.  By specifying a particular composition, there's much less
room for error.

Bruce

On Thu, Dec 8, 2011 at 6:20 PM, Mars brown <itcamefrommars at gmail.com> wrote:
> OK... it took me a couple of days longer to make time to finish it since I
> mentioned it.
> http://www.instructables.com/id/Fast-and-Easy-PCB-Prototyping-with-Vinyl/
>
> It's my first instructable so give me some vicious criticism - I can take
> it!
>
> I think many of you guys have a vinyl cutter in shop... try this out.
> It's one of my personal little tricks that is just stupid easy with perfect
> results.
>
> Cheers!
> - sram|mars
>
> _______________________________________________
> Discuss mailing list
> Discuss at lists.hackerspaces.org
> http://lists.hackerspaces.org/mailman/listinfo/discuss
>