Old Etching solution

[Jamie]

At work, when I do a board I can use their disposal services
rid the old etching solution.

For those that also do this at home in the US, what methods are
used in your area's to depose of such chemical? Recently work has
been complaining about people using their disposal services for home
garbage..

I used to dilute it to a safe level and flush it how ever, this
stuff really stains and the wife does not like it. We do have a
oil, antifreeze etc. place, at our transfer station. Do you guys send
the depleted etching there?

Jamie

 

[mike]

At work, when I do a board I can use their disposal services
rid the old etching solution.

For those that also do this at home in the US, what methods are
used in your area's to depose of such chemical? Recently work has
been complaining about people using their disposal services for home
garbage..

I used to dilute it to a safe level and flush it how ever, this
stuff really stains and the wife does not like it. We do have a
oil, antifreeze etc. place, at our transfer station. Do you guys send
the depleted etching there?

Jamie

Oregon has "neighborhood hazardous waste days". They show up at a school
parking lot and accept residential quantities of stuff for safe
disposal/recycle.
They thank me for accurate labels on all the nasty stuff I take
and have never refused to take anything.

 

[Nico Coesel]

At work, when I do a board I can use their disposal services
rid the old etching solution.

For those that also do this at home in the US, what methods are
used in your area's to depose of such chemical? Recently work has
been complaining about people using their disposal services for home
garbage..

I used to dilute it to a safe level and flush it how ever, this
stuff really stains and the wife does not like it. We do have a
oil, antifreeze etc. place, at our transfer station. Do you guys send
the depleted etching there?

If you use ferric chloride as etchant you can reactivate it by adding
HCl (hydrochloric acid). You never have to dispose it until you want
to get rid of your etching gear.

 

[Cydrome Leader]

If you use ferric chloride as etchant you can reactivate it by adding
HCl (hydrochloric acid). You never have to dispose it until you want
to get rid of your etching gear.

interesting.

Is there some easy trick to know how much HCl to add to regenerate your
solution, and how to get the copper junk out after doing so?

 

[Jamie]

If you use ferric chloride as etchant you can reactivate it by adding
HCl (hydrochloric acid). You never have to dispose it until you want
to get rid of your etching gear.

Hmm, I've never heard of that before. Maybe I should give that a try.

Now, where would I buy this off the shelf in small quantities.

Jamie

 

[Tim Williams]

If you use ferric chloride as etchant you can reactivate it by adding
HCl (hydrochloric acid). You never have to dispose it until you want
to get rid of your etching gear.

Not completely. The copper junk in solution slows it down.

Etching only works if the stuff can stay oxidized. If you don't use it
much, and leave the container open between uses, it will oxidize fairly
well from atmospheric oxygen. Otherwise, adding an oxidizer such as
bleach (sodium hypochlorite), sodium chlorate or hydrogen peroxide, slowly
and with stirring and ventilation (mind the release of chlorine gas!),
will oxidize it back.

Oxidizers will also enhance the etch rate. This is true even of pure
copper chloride (which is the main byproduct of ferric chloride etching),
which etches very slowly, in and of itself.

To remove the excess copper, you have to completely reduce the solution.
The best way to do this is soaking scrap iron in the solution, which
precipitates copper metal and reduces any remaining ferric (adding more
iron to the solution). The resulting ferrous chloride solution must be
oxidized first.

Tim

 

[Martin Riddle]

Hmm, I've never heard of that before. Maybe I should give that a try.

Now, where would I buy this off the shelf in small quantities.

Jamie

A pool supply shop will have HCL on hand, by the Gallon.

Chees

 

[amdx]

At work, when I do a board I can use their disposal services
rid the old etching solution.

For those that also do this at home in the US, what methods are
used in your area's to depose of such chemical? Recently work has
been complaining about people using their disposal services for home
garbage..

I used to dilute it to a safe level and flush it how ever, this

I was told, " The solution to pollution is not dilution"
But as I recall the radio shack etchant bottle said dump it down the
toilet.
MikeK

 

[[email protected]]

Does that include old paint / paint cans?

Vermont had a truck that came around to the dumps every quarter or so, for the
weekend. They'd take any household chemical, including paints. If you didn't
want to wait for the "Rover", you could take the stuff down to the main office
anytime during the weekday. I don't know what we do here. Haven't had
anything like that to get rid of, yet.

Paints can be left to dry and then thrown in the trash. Adding some kitty
litter will speed up the drying. Paint stores also sell a chemical that can
be added to paint to speed up the solidification.

 

[Nico Coesel]

Hmm, I've never heard of that before. Maybe I should give that a try.

Now, where would I buy this off the shelf in small quantities.

Over here: most drug stores and pharmacies sell HCl in 10% strength.
When ferric chloride gets saturated a yellow sludge forms at the
bottom of the tank. Add HCl until that disappears.

 

[[email protected]]

Add plaster, and you get a block that can go in the trash.

HCl can be bought as brick acid from many hardware stores.

AKA Muriatic Acid.

 

[Mark Zenier]

At work, when I do a board I can use their disposal services
rid the old etching solution.

For those that also do this at home in the US, what methods are
used in your area's to depose of such chemical? Recently work has
been complaining about people using their disposal services for home
garbage..

I used to dilute it to a safe level and flush it how ever, this
stuff really stains and the wife does not like it. We do have a
oil, antifreeze etc. place, at our transfer station. Do you guys send
the depleted etching there?

_Electronic Prototype Construction_ written by Dr. Barry Ornitz'
co-worker at Eastman Chemical, Stephen Kasten , says to add it to
mortar mix and send the lump to the landfill.

Mark Zenier [email protected]
Googleproofaddress(account:mzenier provider:eskimo domain:com)

 

[amdx]

At work, when I do a board I can use their disposal services
rid the old etching solution.

For those that also do this at home in the US, what methods are
used in your area's to depose of such chemical? Recently work has
been complaining about people using their disposal services for home
garbage..

I used to dilute it to a safe level and flush it how ever, this
stuff really stains and the wife does not like it. We do have a
oil, antifreeze etc. place, at our transfer station. Do you guys send
the depleted etching there?

Jamie

So what is the procedure?

Do I reduce it with iron.
Add HCI
Then add bleach to oxidize

OR

If I reduce it with iron
Do I skip the HCI
Then add bleach to oxidize.


I have had three or four bottles of used Radio Shack Ferric Chloride
on the shelf for at least 5 years. Can I make it work again?
MikeK

PS. Don't try to warm a glass container full of Ferric Chloride on your
wife's SS burner covers.
The glass cracked and FC leaked through the crack and etched a long line
into the burner cover.
Luckily I noticed the problem before making a huge mess out of the stove.

 

[[email protected]]

Which gives you twice the solution of copper contaminated hydrochloric
acid. As I recall, you can plate the copper out by tossing a pad of
steel wool into the copper loaded solution and the copper will plate
out onto the steel wool. Neither steel nor copper is a hazmat; copper
loaded spent etchant is.

Like many things, its hazmat status likely depends on the quantity.

 

[Nico Coesel]

Which gives you twice the solution of copper contaminated hydrochloric
acid. As I recall, you can plate the copper out by tossing a pad of

Not really. You always lose some liquid due to evaporation. In my
experience you don't need a lot of HCl to reactivate FeCl.

 

[Tim Williams]

So what is the procedure?

Do I reduce it with iron.
Add HCI
Then add bleach to oxidize

OR

If I reduce it with iron
Do I skip the HCI
Then add bleach to oxidize.

You need enough HCl to dissolve the iron gunk, and dissolve the iron
you're adding, AND accommodate the oxidation.

HCl first, then iron. When all copper is precipitated and the iron is
dissolving with the production of hydrogen, the solution is completely
reduced. Run through a filter and begin oxidizing it. If the solution
becomes turbid, add more acid to keep it in solution.

I would recommend using 30% H2O2 because bleach is basic, adds sodium, and
reacts quickly, resulting in lots of chlorine gas, even if you stir it in
quickly.

Sodium chlorate reacts slowly as well, which can be a problem because you
can easily add too much. Although it adds sodium, it doesn't add as much
as bleach does. It can sometimes be found as all purpose weed killer,
particularly in Europe.

I have had three or four bottles of used Radio Shack Ferric Chloride
on the shelf for at least 5 years. Can I make it work again?
MikeK

PS. Don't try to warm a glass container full of Ferric Chloride on your
wife's SS burner covers.

Uh... good idea not to heat a glass container of *anything*. For that
matter, even using glass ovenware these days is risky. Pyrex isn't
"pyrex" anymore.

Tim

 

[Sergey Kubushyn]

Ammonium persulfate doesn't stain, but is a little slower than ferric
chloride. It is also a little more environmentally friendly.

Take a look at

http://faculty.sierracollege.edu/jweir/Webpage14/com/PCBfab Rev D.pdf

pages 10-13.

It is much better than ferric chloride. It also has a great advantage that
it won't etch nickel or solder plated traces that allows for making
plated-through holes.

Unfortunately it has one _MAJOR_ deficiency -- the etching solution don't
last. It is OK for manufacturing when solution is discarded at the end of
day but for a hobby use when one board is etched once a month or so it is a
big waste.

The best one for hobby use is cupric chloride. It is cleaner than ferric
chloride and the solution lasts forever. Dunno how it works on nickel/solder
plated copper but usually it is not an issue in hobby use because it almost
never involves PTH that requires much more chemicals and those chemicals are
quite expensive and not all of them are readily available for a hobbyist.

 

[[email protected]]

Here in Portland OR, if they find paint cans of any description
(full,empty, solid, thick) not only will they dump the cans all over
your yard but also send a rather strongly worded letter not to even
think about doing that again.

That's just stupid, though wouldn't expect otherwise from the weenie left
(coast). There is *nothing* in paint that will harm a landfill, particularly
once dried. Nothing to spill on the way to the dump, either.

So i was interested in an alternate disposal method.

The only good one is to *MOVE*.

WAIT! Maybe i could send them as a gift to His Obamaness?

....and have the Secret Service throw them all over your yard and write the
strongly worded subpoena?

 

[[email protected]]

Which pushes the problem off onto future generations when the mortar
mix decays and puts that stuff into the ground water.

Utter nonsense.

That seems to be a typical thing for our generation ... push the
problem onto our descendants.

Please!

 

[Adrian Tuddenham]

At work, when I do a board I can use their disposal services
rid the old etching solution.

For those that also do this at home in the US, what methods are
used in your area's to depose of such chemical?

That sounds like a problem, not a solution.

[Ho Ho!]