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2011-05-03 by Mark Lerman
If I add 3% H2O2 to regenerate my etchant, I'm adding a lot of water to the mix, so I'm wondering if there's any advantage or disadvantage in bubbling oxygen rather than air through CuCl2 etching solution? Or does the air itself regenerate the solutionadequately in addition to agitating it? Mark
2011-05-03 by javaguy11111
Interesting idea. Especially if you have access to an acetylene torch set. --- In Homebrew_PCBs@yahoogroups.com, Mark Lerman <mlerman@...> wrote:
> > If I add 3% H2O2 to regenerate my etchant, I'm adding a lot of > water to the mix, so I'm wondering if there's any advantage or > disadvantage in bubbling oxygen rather than air through CuCl2 etching > solution? Or does the air itself regenerate the solutionadequately in > addition to agitating it? > > Mark >
2011-05-03 by Jim
Hi Mark I use 27% H2O2 bought at the pool supply store to rejuvenate my etch. I use ~7 ml H2O2 27% per ~300 ml of CuC12. I tried air bubbling and I was not satisfied. If you remember how fast the original etch solution using 3% H2O2 and 30% HCl , this rejuvenated solution is equally as fast. I air bubbled for TWO weeks and the resulting etch was VERY SLOW compared to the ~7ml of 27% H2O2 rejuvenated etch. Jim KI6MZ
On 5/3/2011 5:30 AM, Mark Lerman wrote: > If I add 3% H2O2 to regenerate my etchant, I'm adding a lot of > water to the mix, so I'm wondering if there's any advantage or > disadvantage in bubbling oxygen rather than air through CuCl2 etching > solution? Or does the air itself regenerate the solutionadequately in > addition to agitating it? > > Mark > > > > ------------------------------------ > > Be sure to visit the group home and check for new Links, Files, and Photos: > http://groups.yahoo.com/group/Homebrew_PCBsYahoo! Groups Links > > > > > __________ Information from ESET Smart Security, version of virus signature database 6092 (20110503) __________ > > The message was checked by ESET Smart Security. > > http://www.eset.com > > > >
2011-05-03 by Mark Lerman
Hi Jim, Are you using this at room temperature? Did you make your CuCl2 with H2O2/HCl? If so, what was your starting mixture? Thanks. Mark At 02:58 PM 5/3/2011, you wrote:
>Hi Mark >I use 27% H2O2 bought at the pool supply store to rejuvenate my etch. I >use ~7 ml H2O2 27% per ~300 ml of CuC12. >I tried air bubbling and I was not satisfied. If you remember how fast >the original etch solution using 3% H2O2 and 30% HCl , this rejuvenated >solution is equally as fast. >I air bubbled for TWO weeks and the resulting etch was VERY SLOW >compared to the ~7ml of 27% H2O2 rejuvenated etch. >Jim KI6MZ > >On 5/3/2011 5:30 AM, Mark Lerman wrote: > > If I add 3% H2O2 to regenerate my etchant, I'm adding a lot of > > water to the mix, so I'm wondering if there's any advantage or > > disadvantage in bubbling oxygen rather than air through CuCl2 etching > > solution? Or does the air itself regenerate the solutionadequately in > > addition to agitating it? > > > > Mark > > > > > > > > ------------------------------------ > > > > Be sure to visit the group home and check for new Links, Files, and Photos: > > http://groups.yahoo.com/group/Homebrew_PCBsYahoo! Groups Links > > > > > > > > > > __________ Information from ESET Smart Security, version of virus > signature database 6092 (20110503) __________ > > > > The message was checked by ESET Smart Security. > > > > http://www.eset.com > > > > > > > > > > >------------------------------------ > >Be sure to visit the group home and check for new Links, Files, and Photos: >http://groups.yahoo.com/group/Homebrew_PCBsYahoo! Groups Links > > >
2011-05-03 by Jim
Hi Mark My starting mixture was made with 2 parts of 3%H2O2 and 1 part of 29% HCl. I collected the used etch in a half gallon mason jar with scrap copper in it. When it was full and dark green and not transparent (looked almost black), I took the undissolved copper out. When I need to etch, I pour about 300ml of used etch and add about 7ml of 27%H2O2 and etch at ambient temp outside with vigorous agitation and it will etch a 1.5 x 4 inch ss copper board in about 3 minutes. I use an reciprocating saw attached to a 4 foot long 0.75 x 2 inch board with a fulcrum at the 1 foot from the opposite end of the board from the saw. The PCB with the etch solution in a sealed (snap ware) plastic container is strapped to the short end of the wooden board and the recip saw is turned on and the speed is adjusted until the assembly resonates. It is WILD! The etch is very even. The copper clears evenly and suddenly. Jim KI6MZ
On 5/3/2011 1:04 PM, Mark Lerman wrote: > Hi Jim, > > Are you using this at room temperature? Did you make your CuCl2 with > H2O2/HCl? If so, what was your starting mixture? Thanks. > > Mark > > At 02:58 PM 5/3/2011, you wrote: >> Hi Mark >> I use 27% H2O2 bought at the pool supply store to rejuvenate my etch. I >> use ~7 ml H2O2 27% per ~300 ml of CuC12. >> I tried air bubbling and I was not satisfied. If you remember how fast >> the original etch solution using 3% H2O2 and 30% HCl , this rejuvenated >> solution is equally as fast. >> I air bubbled for TWO weeks and the resulting etch was VERY SLOW >> compared to the ~7ml of 27% H2O2 rejuvenated etch. >> Jim KI6MZ >> >> On 5/3/2011 5:30 AM, Mark Lerman wrote: >>> If I add 3% H2O2 to regenerate my etchant, I'm adding a lot of >>> water to the mix, so I'm wondering if there's any advantage or >>> disadvantage in bubbling oxygen rather than air through CuCl2 etching >>> solution? Or does the air itself regenerate the solutionadequately in >>> addition to agitating it? >>> >>> Mark >>> >>> >>> >>> ------------------------------------ >>> >>> Be sure to visit the group home and check for new Links, Files, and Photos: >>> http://groups.yahoo.com/group/Homebrew_PCBsYahoo! Groups Links >>> >>> >>> >>> >>> __________ Information from ESET Smart Security, version of virus >> signature database 6092 (20110503) __________ >>> The message was checked by ESET Smart Security. >>> >>> http://www.eset.com >>> >>> >>> >>> >> >> ------------------------------------ >> >> Be sure to visit the group home and check for new Links, Files, and Photos: >> http://groups.yahoo.com/group/Homebrew_PCBsYahoo! Groups Links >> >> >> > > ------------------------------------ > > Be sure to visit the group home and check for new Links, Files, and Photos: > http://groups.yahoo.com/group/Homebrew_PCBsYahoo! Groups Links > > > > > __________ Information from ESET Smart Security, version of virus signature database 6092 (20110503) __________ > > The message was checked by ESET Smart Security. > > http://www.eset.com > > > >
2011-05-03 by Jim
On 5/3/2011 1:45 PM, Jim wrote: > Hi Mark > My starting mixture was made with 2 parts of 3%H2O2 and 1 part of 29% > HCl. I collected the used etch in a half gallon mason jar with scrap > copper in it. When it was full and dark green and not transparent > (looked almost black), I took the undissolved copper out. When I need to > etch, I pour about 300ml of used etch and add about 7ml of 27%H2O2 and > etch at ambient temp outside with vigorous agitation and it will etch a > 1.5 x 4 inch ss copper board in about 3 minutes. I use an reciprocating > saw attached to a 4 foot long 0.75 x 2 inch board with a fulcrum at the > 1 foot from the opposite end of the board from the saw. The PCB with the > etch solution in a sealed (snap ware) plastic container is strapped to > the short end of the wooden board and the recip saw is turned on and the > speed is adjusted until the assembly resonates. It is WILD! The etch is > very even. The copper clears evenly and suddenly. <snip> This used etch is returned to the jar.
> Jim KI6MZ > > On 5/3/2011 1:04 PM, Mark Lerman wrote: >> Hi Jim, >> >> Are you using this at room temperature? Did you make your CuCl2 with >> H2O2/HCl? If so, what was your starting mixture? Thanks. >> >> Mark >> >> At 02:58 PM 5/3/2011, you wrote: >>> Hi Mark >>> I use 27% H2O2 bought at the pool supply store to rejuvenate my etch. I >>> use ~7 ml H2O2 27% per ~300 ml of CuC12. >>> I tried air bubbling and I was not satisfied. If you remember how fast >>> the original etch solution using 3% H2O2 and 30% HCl , this rejuvenated >>> solution is equally as fast. >>> I air bubbled for TWO weeks and the resulting etch was VERY SLOW >>> compared to the ~7ml of 27% H2O2 rejuvenated etch. >>> Jim KI6MZ >>> >>> On 5/3/2011 5:30 AM, Mark Lerman wrote: >>>> If I add 3% H2O2 to regenerate my etchant, I'm adding a lot of >>>> water to the mix, so I'm wondering if there's any advantage or >>>> disadvantage in bubbling oxygen rather than air through CuCl2 etching >>>> solution? Or does the air itself regenerate the solutionadequately in >>>> addition to agitating it? >>>> >>>> Mark >>>> >>>> >>>> >>>> ------------------------------------ >>>> >>>> Be sure to visit the group home and check for new Links, Files, and Photos: >>>> http://groups.yahoo.com/group/Homebrew_PCBsYahoo! Groups Links >>>> >>>> >>>> >>>> >>>> __________ Information from ESET Smart Security, version of virus >>> signature database 6092 (20110503) __________ >>>> The message was checked by ESET Smart Security. >>>> >>>> http://www.eset.com >>>> >>>> >>>> >>>> >>> ------------------------------------ >>> >>> Be sure to visit the group home and check for new Links, Files, and Photos: >>> http://groups.yahoo.com/group/Homebrew_PCBsYahoo! Groups Links >>> >>> >>> >> ------------------------------------ >> >> Be sure to visit the group home and check for new Links, Files, and Photos: >> http://groups.yahoo.com/group/Homebrew_PCBsYahoo! Groups Links >> >> >> >> >> __________ Information from ESET Smart Security, version of virus signature database 6092 (20110503) __________ >> >> The message was checked by ESET Smart Security. >> >> http://www.eset.com >> >> >> >> > > ------------------------------------ > > Be sure to visit the group home and check for new Links, Files, and Photos: > http://groups.yahoo.com/group/Homebrew_PCBsYahoo! Groups Links > > > > > __________ Information from ESET Smart Security, version of virus signature database 6092 (20110503) __________ > > The message was checked by ESET Smart Security. > > http://www.eset.com > > > >
2011-05-03 by tda7000
I tried air 'bubbling' too (with am aquarium pump) and got nothing. Then I found this: http://www.youtube.com/watch?v=yT5SdY7nlu8 I think you really need something like that, if you want to go with air regeneration. --- In Homebrew_PCBs@yahoogroups.com, Jim <jhutch17@...> wrote:
> > Hi Mark > I use 27% H2O2 bought at the pool supply store to rejuvenate my etch. I > use ~7 ml H2O2 27% per ~300 ml of CuC12. > I tried air bubbling and I was not satisfied. If you remember how fast > the original etch solution using 3% H2O2 and 30% HCl , this rejuvenated > solution is equally as fast. > I air bubbled for TWO weeks and the resulting etch was VERY SLOW > compared to the ~7ml of 27% H2O2 rejuvenated etch. > Jim KI6MZ > > On 5/3/2011 5:30 AM, Mark Lerman wrote: > > If I add 3% H2O2 to regenerate my etchant, I'm adding a lot of > > water to the mix, so I'm wondering if there's any advantage or > > disadvantage in bubbling oxygen rather than air through CuCl2 etching > > solution? Or does the air itself regenerate the solutionadequately in > > addition to agitating it? > > > > Mark > > > > > > > > ------------------------------------ > > > > Be sure to visit the group home and check for new Links, Files, and Photos: > > http://groups.yahoo.com/group/Homebrew_PCBsYahoo! Groups Links > > > > > > > > > > __________ Information from ESET Smart Security, version of virus signature database 6092 (20110503) __________ > > > > The message was checked by ESET Smart Security. > > > > http://www.eset.com > > > > > > > > >
2011-05-03 by Alessio Sangalli
On 05/03/2011 01:45 PM, Jim wrote: > 1.5 x 4 inch ss copper board in about 3 minutes. I use an reciprocating > saw attached to a 4 foot long 0.75 x 2 inch board with a fulcrum at the > 1 foot from the opposite end of the board from the saw. The PCB with the Make a video!!! bye as
2011-05-03 by Alessio Sangalli
On 05/03/2011 03:42 PM, tda7000 wrote: > Then I found this: http://www.youtube.com/watch?v=yT5SdY7nlu8 I do not understand anything what is being used there... bye as
2011-05-03 by tda7000
He's using an air compressor, not some tiny aquarium pump. It's all there in the comments where I asked him the same question ;) --- In Homebrew_PCBs@yahoogroups.com, Alessio Sangalli <alesan@...> wrote:
> > On 05/03/2011 03:42 PM, tda7000 wrote: > > > Then I found this: http://www.youtube.com/watch?v=yT5SdY7nlu8 > > > I do not understand anything what is being used there... > > bye > as >
2011-05-04 by DJ Delorie
I use a small air bubbler to regenerate, seems to work just fine for me. I turn on the air at the start of the process, so it's running for an hour or so before I etch.
2011-05-04 by Dave
--- In Homebrew_PCBs@yahoogroups.com, DJ Delorie <dj@...> wrote: > > > I use a small air bubbler to regenerate, seems to work just fine for me. > I turn on the air at the start of the process, so it's running for an > hour or so before I etch. Part of the trick is to maximize the area of interaction, which means that a LOT of tiny bubbles are better than big bubbles. Thus, think of the design of the nozzle that blows air into the solution. I wonder if cooling the solution would help, since cooled solutions can usually absorb more air than warm solutions? Would pressurizing the system help? If it could be taken up to a few atmospheres of pressure, would that help the Oxygen dissolve into the solution? (Don't blow up the container!) What about mechanical agitation of the solution? Would sealing the container and placing it on a shaker work? Dave
2011-05-04 by DJ Delorie
"Dave" <wa4qal@...> writes: > Thus, think of the design of the nozzle that blows air into the > solution. There's a row of small holes in the block attached to the air hose. > I wonder if cooling the solution would help, since cooled solutions > can usually absorb more air than warm solutions? I heat my solution so it etches faster ;-) > Would pressurizing the system help? If it could be taken up to a few >atmospheres of pressure, would that help the Oxygen dissolve into the >solution? (Don't blow up the container!) It's not about dissolved oxygen, it's about converting the CuCl from the brown form to the green form.
2011-05-04 by tda7000
That's interesting... mine didn't actually go brown, but it didn't seem to work after the initial use either. Maybe I have a different problem and that's why it won't regenerate? --- In Homebrew_PCBs@yahoogroups.com, DJ Delorie <dj@...> wrote:
> > It's not about dissolved oxygen, it's about converting the CuCl from the > brown form to the green form. >
2011-05-04 by Andrew Leech
On 3/05/2011 10:30 PM, Mark Lerman wrote: > > If I add 3% H2O2 to regenerate my etchant, I'm adding a lot of > water to the mix, so I'm wondering if there's any advantage or > disadvantage in bubbling oxygen rather than air through CuCl2 etching > solution? Or does the air itself regenerate the solutionadequately in > addition to agitating it? > > Mark > I've had the same brew of cucl2 for about 5 years now, and haven't found I ever needed to add h2o2. The only advantage of h2o2 would be very quickly regen it if it's over used (brownish look to fluid) and you need to etch something quickly right now. Air bubbling will take a few hours at least to clear up a well used batch of fluid. These days I don't do a lot of etching, and other than the bubbler and heater running while etching I haven't had to do anything to regen it, the contact with air above the vertical tank (one of the basic off the shelf types) is enough to clear up the liquid. The fluid lives in the tank, which lives in the shed. And I don't have any kids of pets that could get into it, so haven't worried about its safety too much. Back when it was getting much heavier use (previous job) I did bubble it overnight a couple of times, and eventually when saturated with copper it'd precipitate out as a grey sludge on bottom of tank I simply filtered that out with coffee filter paper and add a little hcl to top up the chloride ions. Make sure you filter it before the hcl, adding hcl will dissolve the sludge. Chances are you may never het to the precipitate stage, that only happened after a long time of a lot of use, without adding hcl. Andrew [Non-text portions of this message have been removed]
2011-05-04 by Andrew Leech
On 5/05/2011 8:35 AM, tda7000 wrote: > > That's interesting... mine didn't actually go brown, but it didn't > seem to work after the initial use either. > > Maybe I have a different problem and that's why it won't regenerate? > > --- In Homebrew_PCBs@yahoogroups.com > <mailto:Homebrew_PCBs%40yahoogroups.com>, DJ Delorie <dj@...> wrote: > > > > It's not about dissolved oxygen, it's about converting the CuCl from the > > brown form to the green form. > > > That to me sounds like you don't have enough copper in the solution yet. cucl2 etching relies on an interesting reaction where one form of copper ion in solution will eat off the solid copper and create a different copper ion form. Then you use oxygen to convert the second (non reactive) form back into the first (reactive) form. If you don't have enough copper in the solution (in second form) there won't be enough to convert into the reactive form, and you'll need to add h2o2 to do the reacting instead. Once you've re-used it enough and got plenty of copper ion in solution (brownish colour fluid) then bubble it to get clear green solution. I personally didn't used h2o2 initially, I used a little bit of spent ammonium peroxide etchant that was saturated with copper from lots of use, and then added hcl to that. and added some copper wire to really saturate the brew with copper. Then bubble away! Andrew [Non-text portions of this message have been removed]
2011-05-05 by DJ Delorie
If you can see the pcb AT ALL in the solution, you don't have enough etchant in it yet. Mine is so dark, it's basically black, and I can only see the pcb if it's within 0.3 inches of the sides. I check the color by taking a few drops out and checking that.
2011-05-06 by tda7000
Thanks.. I guess that explains it! I've only done a few boards and the etchant is certainly not dark. So, I just have to keep adding a little hydrogen peroxide to reactivate each time I etch until I've etched enough boards to turn it dark, and then just bubbling will reactivate it? --- In Homebrew_PCBs@yahoogroups.com, DJ Delorie <dj@...> wrote:
> > > If you can see the pcb AT ALL in the solution, you don't have enough > etchant in it yet. Mine is so dark, it's basically black, and I can > only see the pcb if it's within 0.3 inches of the sides. I check the > color by taking a few drops out and checking that. >
2011-05-08 by DJ Delorie
"tda7000" <Tda7000@...> writes: > So, I just have to keep adding a little hydrogen peroxide to > reactivate each time I etch until I've etched enough boards to turn it > dark, and then just bubbling will reactivate it? Until you've converted it, you still have an HCl/H2O2 etchant. The H2O2 breaks down over time, and the HCl evaporates, leaving you with just water. So, if you're doing this over time, the thing to do is mix only enough HCl/H2O2 etchant for your board-du-jour, and keep adding it to your etchant tank. Over time, the CuCl builds up, and you need less HCl/H2O2 for each board, and can start with the CuCl chemistry checks to see what you need (HCl or H2O2) each time you etch. Also you can keep a chunk of copper in the etchant when you're not using it, so the excess HCl/H2O2 doesn't go to waste. A copper plumbing part will do, like an elbow. Just remember to take it out before adding the new etchant ;-) Remember, the etch does Cu + Cl => CuCl, so you have to have free Cl in the etchant also! H2O2 alone is not enough.
2011-05-08 by Jim
My jar of CuCl ?? was transparent emerald green(~55 Oz.). I put some more copper scraps in it and turned on the bubblier. It ran for 2 days. The contents of the jar turned DARK OPAQUE green. I removed the solid copper scraps and started the bubblier again. I ran it 2 days and the contents of the jar was still DARK OPAQUE green. I added 2 Oz of HCL ... no change. I added 1 Oz of 27% H2O2 and the contents of the jar turned transparent emerald green. ... are we there yet ?? Jim KI6MZ
On 5/8/2011 4:49 AM, DJ Delorie wrote: > "tda7000"<Tda7000@...> writes: >> So, I just have to keep adding a little hydrogen peroxide to >> reactivate each time I etch until I've etched enough boards to turn it >> dark, and then just bubbling will reactivate it? > Until you've converted it, you still have an HCl/H2O2 etchant. The H2O2 > breaks down over time, and the HCl evaporates, leaving you with just > water. So, if you're doing this over time, the thing to do is mix only > enough HCl/H2O2 etchant for your board-du-jour, and keep adding it to > your etchant tank. Over time, the CuCl builds up, and you need less > HCl/H2O2 for each board, and can start with the CuCl chemistry checks to > see what you need (HCl or H2O2) each time you etch. Also you can keep a > chunk of copper in the etchant when you're not using it, so the excess > HCl/H2O2 doesn't go to waste. A copper plumbing part will do, like an > elbow. Just remember to take it out before adding the new etchant ;-) > > Remember, the etch does Cu + Cl => CuCl, so you have to have free Cl in > the etchant also! H2O2 alone is not enough. > > > ------------------------------------ > > Be sure to visit the group home and check for new Links, Files, and Photos: > http://groups.yahoo.com/group/Homebrew_PCBsYahoo! Groups Links > > > > > __________ Information from ESET Smart Security, version of virus signature database 6105 (20110508) __________ > > The message was checked by ESET Smart Security. > > http://www.eset.com > > > >
2011-05-09 by DJ Delorie
The only way to know how "strong" your CuCl etchant is, is to use a hydrometer. The copper makes the solution more dense, by measuring the density you can determine the copper concentration. See http://members.optusnet.com.au/~eseychell/PCB/etching_CuCl/ for all the details. Note: my solution looks like the photo at the top of Adam's page. "Spent" etchant is opaque BROWN. This may look like dark green at first because it's mixed, but see Figure 5 on Adam's page.
2011-05-09 by Jim
Thanks DJ Last week I had a 55 oz jar of transparent emerald green etch. Using this etch was SLLLOW. I added scrap copper and started bubbling. It took about 10 hours to turn OPAQUE. I continued to bubble for another 24 hours. Removed the copper and continued bubbling. After 2 days, it was still OPAQUE. I added 2 oz HCl ... no change ... 1 oz of 27% H2O2 ... it turned emerald green. With the additional HCL, I added more copper and started bubbling. It took 8 hours for it to turn OPAQUE. I continued bubbling for another 4 hours. I removed the copper and continued bubbling and after 6 hours it turned transparent emerald green. I don't have an hydrometer. The color is a transparent BRIGHT emerald green no trouble seeing through the 5 inch diameter jar of etch ... no hint of OLIVE green. Should I add more copper? ... When Adam says you can't see through but a few mm, Is that the ready to etch transparent state or the spent OPAQUE state? Jim KI6MZ
On 5/9/2011 11:46 AM, DJ Delorie wrote: > The only way to know how "strong" your CuCl etchant is, is to use a > hydrometer. The copper makes the solution more dense, by measuring > the density you can determine the copper concentration. > > See http://members.optusnet.com.au/~eseychell/PCB/etching_CuCl/ > for all the details. > > Note: my solution looks like the photo at the top of Adam's page. > > "Spent" etchant is opaque BROWN. This may look like dark green at first > because it's mixed, but see Figure 5 on Adam's page. > > > ------------------------------------ > > Be sure to visit the group home and check for new Links, Files, and Photos: > http://groups.yahoo.com/group/Homebrew_PCBsYahoo! Groups Links > > > > > __________ Information from ESET Smart Security, version of virus signature database 6107 (20110509) __________ > > The message was checked by ESET Smart Security. > > http://www.eset.com > > > >
2011-05-09 by Andrew Leech
On 10/05/2011 6:21 AM, Jim wrote: > > Thanks DJ > Last week I had a 55 oz jar of transparent emerald green etch. Using > this etch was SLLLOW. I added scrap copper and started bubbling. It took > about 10 hours to turn OPAQUE. I continued to bubble for another 24 > hours. Removed the copper and continued bubbling. After 2 days, it was > still OPAQUE. I added 2 oz HCl ... no change ... 1 oz of 27% H2O2 ... it > turned emerald green. With the additional HCL, I added more copper and > started bubbling. It took 8 hours for it to turn OPAQUE. I continued > bubbling for another 4 hours. I removed the copper and continued > bubbling and after 6 hours it turned transparent emerald green. I don't > have an hydrometer. The color is a transparent BRIGHT emerald green no > trouble seeing through the 5 inch diameter jar of etch ... no hint of > OLIVE green. Should I add more copper? ... When Adam says you can't see > through but a few mm, Is that the ready to etch transparent state or the > spent OPAQUE state? > Jim KI6MZ > > On 5/9/2011 11:46 AM, DJ Delorie wrote: > > The only way to know how "strong" your CuCl etchant is, is to use a > > hydrometer. The copper makes the solution more dense, by measuring > > the density you can determine the copper concentration. > > > > See http://members.optusnet.com.au/~eseychell/PCB/etching_CuCl/ > <http://members.optusnet.com.au/%7Eeseychell/PCB/etching_CuCl/> > > for all the details. > > > > Note: my solution looks like the photo at the top of Adam's page. > > > > "Spent" etchant is opaque BROWN. This may look like dark green at first > > because it's mixed, but see Figure 5 on Adam's page. > > > The bright clear green should be ready-to-etch state. Opaque means it's spent state. Here's a great resource on the chemistry behind it with really good pictures: http://members.optusnet.com.au/~eseychell/PCB/etching_CuCl/index.html <http://members.optusnet.com.au/%7Eeseychell/PCB/etching_CuCl/index.html> Andrew [Non-text portions of this message have been removed]
2011-05-10 by H1000100
I made 2 liters of the stuff in a coke bottle. I didn't have a hygrometer, but I weighed it on a kitchen scale and kept adding more copper till it was heavy enough. Regenerating with 35% H202 is nearly instant.