Homebrew_PCBs

>What about ammonium persulfate ? when I worked at the electronics plant that
>was what we used to etch our boards. It is clear and turns blue as it etches
>. we used to put it in a corningware baking pan and warm it with a hot plate
>underneath . if you put more into the mix it of course eats away the copper
>faster. In time it will take the shine off the corningware in the area where
>the heat source was.

>
>Have also used ferric chloride , it also works better if you warm it. Ferric
>chloride is usually used in sewage treatment plants to coagulate the solids.

>
>
>
>From: Homebrew_PCBs@yahoogroups.com [mailto:Homebrew_PCBs@yahoogroups.com]
>Sent: Friday, May 27, 2016 8:07 PM
>To: Homebrew_PCBs Mailing List
>Subject: [Homebrew_PCBs] Substitute for Sodium Persulphate
>
>
>
>
>
>I have a commercial etching tank, composed of formed acrylic plastic
>and two fish tank pumps.
>
>It's designed for sodium persulphate etchant.
>
>I can get a pool shock persulphate etchant for about 10 dollars for 1
>KG, and you need about 1 KG for a single run (no idea how many boards
>that is, but it's about 1-2 gallons of etchant).
>
>The normal HCl/H2O2 etchant that I use would no doubt eat the pumps to
>pieces.
>
>So a question would be: Can I use high concentration H2O2 (say from a
>beauty supply store, no idea how much that might be, but presumably
>less than the 1.25 dollars/quart that I can get H2O2 for...)? Just by
>itself, I suspect that it might not work, would activating that
>etchant with a little chloride ions (perhaps salt?) work?
>
>Has anyone looked for a substitute for Sodium persulphate (potassium
>persulphate will also work, but equally expensive, I think)?
>
>Is there an etchant that will work for this kind of situation?
>
>Harvey
>
>

>Normally you use a bubbler to agitate a small tank, and the pumps are not in the solution.

>Bubbling also regenerates the cupric chloride which is what is actually performing the etch. The HCl/Peroxide mix will quickly eat nylon but most other plastics don't seem to be bothered. Epoxy glue is attacked but slowly. If you're building your own tank, test the materials first.

>
>Adam Seychell used to have a web page describing the process, but his site seems to be gone.I had to get it from the wayback machine. Jim Williams has duplicated Seychell's page at Etching with Air Regenerated Acid Cupric Chloride http://jimlaurwilliams.org/projects/seychellePaper/
>
> http://jimlaurwilliams.org/projects/seychellePaper/
>
> Etching with Air Regenerated Acid Cupric Chloride http://jimlaurwilliams.org/projects/seychellePaper/ Etching with Air Regenerated Acid Cupric Chloride By Adam Seychell (Last modified 5 November 2005)
>
>
>
> View on jimlaurwilliam... http://jimlaurwilliams.org/projects/seychellePaper/
> Preview by Yahoo
>
>
>

> On Sat, 28 May 2016 09:29:41 -0400, you wrote:
>
>> What about ammonium persulfate ? when I worked at the electronics plant that
>> was what we used to etch our boards. It is clear and turns blue as it etches
>> . we used to put it in a corningware baking pan and warm it with a hot plate
>> underneath . if you put more into the mix it of course eats away the copper
>> faster. In time it will take the shine off the corningware in the area where
>> the heat source was.
>
> Same kind of problem with price, I think. I could only buy it from a
> chemical supply plant, and it's rather expensive.
>
>> Have also used ferric chloride, it also works better if you warm it. Ferric
>> chloride is usually used in sewage treatment plants to coagulate the solids.
>
> Had used that for years, hard to find in good sized lots, 30
> bucks/gallon or more plus shipping.
>
> Peroxide and muriatic acid is far cheaper.
>
> If I could find a cheap source of ammonium persulphate, that would be
> nice.
>
> The stuff in the pool supply stores (Oxy-shock) is 10 bucks/kilo, and
> has trace ingredients (undisclosed). It does work, but I'm not happy
> at that price.

-- 
John Ferrell W8CCW
   Julian NC 27283
 It is better to walk alone,
than with a crowd going the wrong direction.
                  --Diane Grant

>Read the MDS. It is pretty safe stuff. About a million years ago I was a
>Lab Tech and HCl was used to wash ink off our hands.
>Beauty shop peroxide is about 30% and over $30 per gallon. The drug
>store stuff works and $1 per Qt. I wash all wounds with the $1 peroxide
>and some people use it for mouth wash.
>It also leaves bleach dot on you clothing.

Read the MDS. It is pretty safe stuff. About a million years ago I was a Lab Tech and HCl was used to wash ink off our hands.
Beauty shop peroxide is about 30% and over $30 per gallon. The drug store stuff works and $1 per Qt. I wash all wounds with the $1 peroxide and some people use it for mouth wash.
It also leaves bleach dot on you clothing.

-- 
John Ferrell W8CCW
   Julian NC 27283
 It is better to walk alone,
than with a crowd going the wrong direction.
                  --Diane Grant

>If you use the Beauty Shop peroxide be aware that the etching is violently exothermic. Lots of heat and fumes. The etching goes very fast. Done in seconds.

>
>I use the drug store version mixed 2:1 with muriatic acid from the hardware store. Instead of immersing the board I use a sponge and gently rub the copper. This allows you to control where you need the etching. Obviously, wear gloves.
>
>I'm not sure who first described this technique, but it gives you good control and only takes a few minutes. It also lets you use a very small amount of etchant.
>
>Mark
>
>Sent from my iPhone
>
>> On May 28, 2016, at 2:53 PM, John Ferrell jferrell13@... [Homebrew_PCBs] <Homebrew_PCBs@yahoogroups.com> wrote:
>>
>>
>>
>> Read the MDS. It is pretty safe stuff. About a million years ago I was a Lab Tech and HCl was used to wash ink off our hands.
>> Beauty shop peroxide is about 30% and over $30 per gallon. The drug store stuff works and $1 per Qt. I wash all wounds with the $1 peroxide and some people use it for mouth wash.
>> It also leaves bleach dot on you clothing.
>> --
>> John Ferrell W8CCW
>> Julian NC 27283
>> It is better to walk alone,
>> than with a crowd going the wrong direction.
>> --Diane Grant
>>
>>
>>

> On May 28, 2016, at 6:05 PM, Harvey White madyn@... [Homebrew_PCBs] <Homebrew_PCBs@yahoogroups.com> wrote:
>
> On Sat, 28 May 2016 16:50:45 -0400, you wrote:
>
> >If you use the Beauty Shop peroxide be aware that the etching is violently exothermic. Lots of heat and fumes. The etching goes very fast. Done in seconds.
>
> I'd be using it to boost the O2 concentration of the etchant, which
> hopefully works, since the peroxide by itself I can see as not being
> much different from the ammonium persulphate except for the ammonia
> ions (and sulphate ions).
>
> In theory, the drugstore peroxide might etch sufficiently by itself,
> then the question is either to put a gallon or so of that in, or
> refresh it by the beauty shop peroxide.
>
> I'm trying to avoid the CuCl etchant, or at least, the HCL part of it.
>
> Harvey
>
> >
> >I use the drug store version mixed 2:1 with muriatic acid from the hardware store. Instead of immersing the board I use a sponge and gently rub the copper. This allows you to control where you need the etching. Obviously, wear gloves.
> >
> >I'm not sure who first described this technique, but it gives you good control and only takes a few minutes. It also lets you use a very small amount of etchant.
> >
> >Mark
> >
> >Sent from my iPhone
> >
> >> On May 28, 2016, at 2:53 PM, John Ferrell jferrell13@... [Homebrew_PCBs] <Homebrew_PCBs@yahoogroups.com> wrote:
> >>
> >>
> >>
> >> Read the MDS. It is pretty safe stuff. About a million years ago I was a Lab Tech and HCl was used to wash ink off our hands.
> >> Beauty shop peroxide is about 30% and over $30 per gallon. The drug store stuff works and $1 per Qt. I wash all wounds with the $1 peroxide and some people use it for mouth wash.
> >> It also leaves bleach dot on you clothing.
> >> --
> >> John Ferrell W8CCW
> >> Julian NC 27283
> >> It is better to walk alone,
> >> than with a crowd going the wrong direction.
> >> --Diane Grant
> >>
> >>
> >>
>
>
>

>Harvey,
>
>The hydrogen peroxide alone will NEVER etch copper. it is H2O2 (very strong oxidizer),
>so the only thing that it could do is to oxidize a thin layer of copper (black).
>
>In order to etch, you need ions Cl- to create green cupric chloride CuCl2 (dissolve in water).
>So you need the hydrochloric acid (muriatic) to convert the copper oxide to cupric chloride.
>
>Hence the combination Hal-H2O2 that will etch copper very fast.
>To regenerate the etchant, you use a bubbler that will bring O2 ( O= ions) in the solution.

>
>My $0.02,
>Jean-Paul
>N1 JPL
>
>
>
>> On May 28, 2016, at 6:05 PM, Harvey White madyn@... [Homebrew_PCBs] <Homebrew_PCBs@yahoogroups.com> wrote:
>>
>> On Sat, 28 May 2016 16:50:45 -0400, you wrote:
>>
>> >If you use the Beauty Shop peroxide be aware that the etching is violently exothermic. Lots of heat and fumes. The etching goes very fast. Done in seconds.
>>
>> I'd be using it to boost the O2 concentration of the etchant, which
>> hopefully works, since the peroxide by itself I can see as not being
>> much different from the ammonium persulphate except for the ammonia
>> ions (and sulphate ions).
>>
>> In theory, the drugstore peroxide might etch sufficiently by itself,
>> then the question is either to put a gallon or so of that in, or
>> refresh it by the beauty shop peroxide.
>>
>> I'm trying to avoid the CuCl etchant, or at least, the HCL part of it.
>>
>> Harvey
>>
>> >
>> >I use the drug store version mixed 2:1 with muriatic acid from the hardware store. Instead of immersing the board I use a sponge and gently rub the copper. This allows you to control where you need the etching. Obviously, wear gloves.
>> >
>> >I'm not sure who first described this technique, but it gives you good control and only takes a few minutes. It also lets you use a very small amount of etchant.
>> >
>> >Mark
>> >
>> >Sent from my iPhone
>> >
>> >> On May 28, 2016, at 2:53 PM, John Ferrell jferrell13@... [Homebrew_PCBs] <Homebrew_PCBs@yahoogroups.com> wrote:
>> >>
>> >>
>> >>
>> >> Read the MDS. It is pretty safe stuff. About a million years ago I was a Lab Tech and HCl was used to wash ink off our hands.
>> >> Beauty shop peroxide is about 30% and over $30 per gallon. The drug store stuff works and $1 per Qt. I wash all wounds with the $1 peroxide and some people use it for mouth wash.
>> >> It also leaves bleach dot on you clothing.
>> >> --
>> >> John Ferrell W8CCW
>> >> Julian NC 27283
>> >> It is better to walk alone,
>> >> than with a crowd going the wrong direction.
>> >> --Diane Grant
>> >>
>> >>
>> >>
>>
>>
>>

Thanks, that's what I need. I understand regenerating the etchant. If
I supply chloride ions (say from salt), think it will work? I'm
guessing that the HCL is what makes CuCl so destructive to things like
nylon.

any opinions?

Harvey


>> I'm trying to avoid the CuCl etchant, or at least, the HCL part of it.
>>
>> Harvey
>>

Harvy -

You really need to get the Adam Sechelle (sp?) article on CuCl etching.  It explains the chemistry involved in removing the copper.  Just putting salt (NaCl) in water won't release free Cl ions.  When the copper is removed, it has to go somewhere, and that is into solution as CuCl.  The etching (removal of the copper) relies  on the formation of CuCl and the reversible reaction between CuCl+ and CuCl++.  I know this isn't what you want to hear, but the chemistry is factual. 

Norm

>>
>Harvy -
>
>You really need to get the Adam Sechelle (sp?) article on CuCl etching.
>It explains the chemistry involved in removing the copper. Just putting
>salt (NaCl) in water won't release free Cl ions. When the copper is
>removed, it has to go somewhere, and that is into solution as CuCl. The
>etching (removal of the copper)***/relies /*on the formation of CuCl and
>the reversible reaction between CuCl+ and CuCl++. I know this isn't
>what you want to hear, but the chemistry is factual.

>
>Norm

  DuWayne

 

I use the Muriatic Acid, Hydrogen Peroxide mixture with 12% Peroxide from a beauty supply store with good success. If you do not want to use the HCL, another solution that is sometimes used is a mixture of Hydrogen Peroxide, Vinegar, and salt.

But mixing vinegar (acetic acid) and salt (sodium chloride)  results  in HCl  !  Just another way of generating a weak solution of it. !

Norm

> Just as an FYI I use Nitric acid, and have been doing so since 1987.
> Fairly easy to handle at the lowish concentration in the etchant tank. I
> can handle the boards with bare fingers once I get them rinsed inside of
> 10 seconds so I etch next to the rinse tub sink, although I generally
> use plastic tongs/tweezers. My etchant tank is an ice cream container
> as nitric is plastic safe as well. No heating required, but minor
> ventilation is, it self agitates due to some bubbling during etching. No
> staining etc, clear liquid and does not degrade when dilute. Lasts for
> many years.
>
> Harder to come by in the U.S.A. but if you hold a tertiary degree you
> can buy it from lab chemical supply companies. I am not in the U.S.A.
> and obtain it direct from my old University in carboyles.
>
> I mix down the concentrated stuff to 1.2 Sp. grav to 1.22 Sp grav. for a
> fresh batch as required (acid adds to water). Resultant etch in 5 to 8
> mins double sided, 1 oz. Detail traces to 8 mils using the toner
> transfer/foiling method. No heating or agitation required. Suitable for
> quick and dirty sharpie marker traces, black or silver pens, silver is
> better. Black ink needs to be dried properly (hot air speeds that).
>
> The waste is acidified copper nitrate which is not a hazmat. Good for
> drain cleaning/sewer lines, anti fungal use etc.