You can get 30% HCL cheap - home depot. its used for acid rinse on
masonary.
The H2O2 from the drug store (3%) isn't strong enough except perhaps
for the initial creation of the mix. I got mine (35%) from a
scientific supply place but it was way too expensive. I have heard of
people getting stronger H2O2 from drugstores but none in my area carry
anything other than 3%. I'm sure Chicago must have some source of
reasonably priced H2O2.
Acrylic is very easy to glue. Cutting is tricky, though. Get the
special knife and it goes much easier.
I have about 2 quarts of CuCl in a cereal container - its holding up
ok. HDPE.
By the way, anyone want my CuCl? Seattle area pickup. free.
Chris, you really should at least look at Ammonium Persulphate. For
casual etching, it really is a great way to go.
Phil
--- In
Homebrew_PCBs@yahoogroups.com, "lcdpublishing"
<lcdpublishing@y...> wrote:
> Okay, starting to make some sense. But, finding and buying
> chemicals isn't the easiest thing to do these days.
>
> So, a couple of follow up questions.....
>
>
> hydrogen peroxide (H2O2), is this the same as what I can purchase at
> the local drug store? Or, is there a stronger solution or something
> I have to get at a specialty supplier?
>
>
> hydrochloric acid (HCl), I know I have seen this for some purposes
> but can't recall common uses - toilet bowl cleaner perhaps? Again,
> where would I purchase this, and is there a certain strength I
> should look for?
>
>
> With this chemical make up, do you still want to use a heater?
>
> Does anyone know which plastics will be okay to use as a tank for
> this type of etching? I was thinking of using Acrylics, but that
> stuff can be a pain in the ass to glue up good. Then I thought
> about polystyrene which you can get translucent and I believe it can
> be glued up more readily.
>
> TIA, I am getting closer to understanding it :-)
>
> Chris
>
>
>
>
>
>
>
>
>
>
>
>
>
>
> --- In Homebrew_PCBs@yahoogroups.com, "Stefan Trethan"
> <stefan_trethan@g...> wrote:
> > On Sat, 20 Aug 2005 02:38:22 +0200, <JanRwl@A...> wrote:
> >
> > > Can someone here PLEASE outline the procedure and chemistry to
> use for
> > > this
> > > etch-method? I have never seen ANYWHERE a list like,
> > > "1. Boil the bare blank in swamp-water;
> > > 2. Incant;
> > > 3. Swish the board around in a 30% CuCl solution over 80°C
> for 15
> > > minutes;
> > > 4, Etc. etc."
> > > With FeCl, you can omit steps 2. and 4., and the result is
> fine, but
> > > messy.
> > > Please?
> >
> >
> > I'll try.
> > Let's divide that into 3 parts:
> > Etching boards, maintainance, and first "brewing" of CuCl.
> >
> >
> > For normal etching, you'd need to do nothing much. You'd just put
> a board
> > in, and add H2O2 if the etchant is too dark in color. a few ml is
> enough
> > to oxidize it. The color is all you need to determine if it is ok
> or needs
> > something. Then you turn on the bubbler and simply wait until
> done.
> > Nothing needs to be done after etching.
> >
> > The adding of hydrogen peroxide (H2O2) takes the hydrogen away
> from some
> > of the hydrochloric acid (HCl). That means the chlorine is freed
> and can
> > "take" one copper from Cu2Cl (the dark brown stuff) to form more
> CuCl
> > (light green), and water. CuCl is now prepared to take a second
> copper
> > again, thus etch the board. You can also introduce the oxygen from
> other
> > sources, like pumping air through it (takes long), or even
> chlorine gas
> > directly, but that's poisonous.
> >
> >
> > maintainance:
> > From time to time you might want to measure the molarity of the
> HCl in
> > there. That is, how many hydrochloric acid is still "free" (not
> carrying
> > copper) and can be used to form CuCl. Because every time you add
> H2O2 some
> > of the HCl is converted into CuCl. At some point, if all HCl is
> used up,
> > adding H2O2 will not bring on the expected brigtening of the
> etchant and
> > increase in etch speed. Also, the etchant will have a bluish color
> ad
> > deposit a blue sludge on boards. This is a sure indicator there is
> not
> > enough HCl, but you sould have added some by then.
> >
> > To measure the HCl molarity, you need 4 things. A alkaline
> solution of
> > known molarity (NaOH), some indicator (like methylorange), and
> two
> > eyedroppers. You can get your NaOH solution by solving a weighed
> amount of
> > developer in water. It should be a 1 molar solution. How much you
> need to
> > weigh is said in one of the pages in the links section. When you
> have that
> > the procedure is simple. Put 10 drops of etchant in a small
> container, add
> > some water if you like, and one drop of indicator. It's now
> orange. Then
> > add the alkaline solution drop by drop, all the time swishing the
> > container to mix it. When it turns green stop and your number of
> alkaline
> > solution drops added is your molarity after dividing by 10.
> > I don't do that often, and usually only add HCl by feel. A wide
> range of
> > molarity will be ok. I keep it around 1. Still every few months i
> feel
> > like checking the molarity.
> >
> > There's also the density to be measured. Adding the copper makes
> the
> > etchant more "heavy". In a away this is good - because you'll have
> more
> > CuCl do do the etching. But if it gets too much you need to remove
> some
> > etchant and add water. I have never encountered this, i guess the
> water in
> > the HCl and H2O2 added is enough. You can measure the density with
> a
> > hydrometer, which you can simply by in a car parts store, as a
> tool for
> > checking car battery acid. It comes in a neat huge "eyedropper" in
> which
> > the hydrometer swims.
> >
> >
> > First brewing:
> > Some tutorials call for adding copper in some form.
> > I have found you can start just as well with only HCl and H2O2,
> and water.
> > At first, you don't have any CuCl, but those two chemicals will
> etch all
> > by themself. You can make etchant up by diluting HCl to about 10%
> and
> > adding a swig of H2O2. Then put in the board and go by color.
> > At first there is none or little CuCl, so you have to add some
> H2O2 each
> > time you etch. As copper content increases you get more and more
> CuCl,
> > which does the etching and must only be re-oxidized from time to
> time. I'm
> > now at a stage where i need to add H2O2 maybe each third or fourth
> board.
> >
> > Here you go.
> >
> > ST