Synth-DIY Yahoo! Groups Archives

Thread

Acid etch time

2012-07-09 by txtom2

I just mixed up some Muriatic Acid and Hydrogen Peroxide (1:2) and tried etching a very small piece of PC board (cleaned and with no mask)to see how long it takes to etch thru (room temp about 75 degrees F). I saw a change in surface color in a couple of minutes, but no etch thru after 15 minutes. I changed the ratio to 2:2 to increase the acid content and after 15 minutes, no further apparent progress. 

Can someone please tell me what I'm doing wrong ? About how long should it take to etch ??

Thanks,  Tom

Re: Acid etch time

2012-07-09 by leeleduc

I use this technique all the time. I can do a 2X4 inch, 1 ounce board in about 1.5 to 2 minutes.
I use 1 Part 31% HCL and 2 Parts 3% H2O2. I make just enough etchant to cover the
board about 1/8 to 1/4 inch and lightly brush the surface with a foam Paint
brush. I etch at room temperature. Works very well for me. Make sure your chemicals are fresh, especially the peroxide.

--- In Homebrew_PCBs@yahoogroups.com, "txtom2" <unknown2@...> wrote:

Show quoted textHide quoted text

>
> I just mixed up some Muriatic Acid and Hydrogen Peroxide (1:2) and tried etching a very small piece of PC board (cleaned and with no mask)to see how long it takes to etch thru (room temp about 75 degrees F). I saw a change in surface color in a couple of minutes, but no etch thru after 15 minutes. I changed the ratio to 2:2 to increase the acid content and after 15 minutes, no further apparent progress. 
> 
> Can someone please tell me what I'm doing wrong ? About how long should it take to etch ??
> 
> Thanks,  Tom
>

Re: Acid etch time

2012-07-09 by tda7000

I had a slow etch problem last time I made a board.
I think the temperature was rather low (I was doing it on a winter evening) also my chemicals are rather old.

After nothing much doing after 15 minutes or so, I poured boiling water into a dish and set my etching tub on top. Went like crazy after that.


--- In Homebrew_PCBs@yahoogroups.com, "leeleduc" <leeleduc@...> wrote:

Show quoted textHide quoted text

>
> I use this technique all the time. I can do a 2X4 inch, 1 ounce board in about 1.5 to 2 minutes.
> I use 1 Part 31% HCL and 2 Parts 3% H2O2. I make just enough etchant to cover the
> board about 1/8 to 1/4 inch and lightly brush the surface with a foam Paint
> brush. I etch at room temperature. Works very well for me. Make sure your chemicals are fresh, especially the peroxide.
> 
> --- In Homebrew_PCBs@yahoogroups.com, "txtom2" <unknown2@> wrote:
> >
> > I just mixed up some Muriatic Acid and Hydrogen Peroxide (1:2) and tried etching a very small piece of PC board (cleaned and with no mask)to see how long it takes to etch thru (room temp about 75 degrees F). I saw a change in surface color in a couple of minutes, but no etch thru after 15 minutes. I changed the ratio to 2:2 to increase the acid content and after 15 minutes, no further apparent progress. 
> > 
> > Can someone please tell me what I'm doing wrong ? About how long should it take to etch ??
> > 
> > Thanks,  Tom
> >
>

Re: [Homebrew_PCBs] Re: Acid etch time

2012-07-10 by Slavko Kocjancic

If you leave peroxide (3%) on sun for day or two it's unusable for 
etching. It must be stored in the dark place. In light it's disolve to 
Oxigen and pure water.


Dne 10.7.2012 0:52, pi\ufffde tda7000:

Show quoted textHide quoted text

> I had a slow etch problem last time I made a board.
> I think the temperature was rather low (I was doing it on a winter evening) also my chemicals are rather old.
>
> After nothing much doing after 15 minutes or so, I poured boiling water into a dish and set my etching tub on top. Went like crazy after that.
>
>
> --- In Homebrew_PCBs@yahoogroups.com, "leeleduc" <leeleduc@...> wrote:
>> I use this technique all the time. I can do a 2X4 inch, 1 ounce board in about 1.5 to 2 minutes.
>> I use 1 Part 31% HCL and 2 Parts 3% H2O2. I make just enough etchant to cover the
>> board about 1/8 to 1/4 inch and lightly brush the surface with a foam Paint
>> brush. I etch at room temperature. Works very well for me. Make sure your chemicals are fresh, especially the peroxide.
>>
>> --- In Homebrew_PCBs@yahoogroups.com, "txtom2" <unknown2@> wrote:
>>> I just mixed up some Muriatic Acid and Hydrogen Peroxide (1:2) and tried etching a very small piece of PC board (cleaned and with no mask)to see how long it takes to etch thru (room temp about 75 degrees F). I saw a change in surface color in a couple of minutes, but no etch thru after 15 minutes. I changed the ratio to 2:2 to increase the acid content and after 15 minutes, no further apparent progress.
>>>
>>> Can someone please tell me what I'm doing wrong ? About how long should it take to etch ??
>>>
>>> Thanks,  Tom
>>>
>
>
>
> ------------------------------------
>
> Be sure to visit the group home and check for new Links, Files, and Photos:
> http://groups.yahoo.com/group/Homebrew_PCBsYahoo! Groups Links
>
>
>
>

Re: Acid etch time

2012-07-10 by tda7000

Well, I keep mine in the white (not transparent) bottles it comes in, in the shed, so it's probably not getting much light if any. 

--- In Homebrew_PCBs@yahoogroups.com, Slavko Kocjancic <eslavko@...> wrote:

Show quoted textHide quoted text

>
> If you leave peroxide (3%) on sun for day or two it's unusable for 
> etching. It must be stored in the dark place. In light it's disolve to 
> Oxigen and pure water.
> 
> 
> Dne 10.7.2012 0:52, pie tda7000:
> > I had a slow etch problem last time I made a board.
> > I think the temperature was rather low (I was doing it on a winter evening) also my chemicals are rather old.
> >
> > After nothing much doing after 15 minutes or so, I poured boiling water into a dish and set my etching tub on top. Went like crazy after that.
> >
> >
> > --- In Homebrew_PCBs@yahoogroups.com, "leeleduc" <leeleduc@> wrote:
> >> I use this technique all the time. I can do a 2X4 inch, 1 ounce board in about 1.5 to 2 minutes.
> >> I use 1 Part 31% HCL and 2 Parts 3% H2O2. I make just enough etchant to cover the
> >> board about 1/8 to 1/4 inch and lightly brush the surface with a foam Paint
> >> brush. I etch at room temperature. Works very well for me. Make sure your chemicals are fresh, especially the peroxide.
> >>
> >> --- In Homebrew_PCBs@yahoogroups.com, "txtom2" <unknown2@> wrote:
> >>> I just mixed up some Muriatic Acid and Hydrogen Peroxide (1:2) and tried etching a very small piece of PC board (cleaned and with no mask)to see how long it takes to etch thru (room temp about 75 degrees F). I saw a change in surface color in a couple of minutes, but no etch thru after 15 minutes. I changed the ratio to 2:2 to increase the acid content and after 15 minutes, no further apparent progress.
> >>>
> >>> Can someone please tell me what I'm doing wrong ? About how long should it take to etch ??
> >>>
> >>> Thanks,  Tom
> >>>
> >
> >
> >
> > ------------------------------------
> >
> > Be sure to visit the group home and check for new Links, Files, and Photos:
> > http://groups.yahoo.com/group/Homebrew_PCBsYahoo! Groups Links
> >
> >
> >
> >
>

Acid etch time

2012-07-10 by Peter

Never tried acid etching myself. This might be worth noting:
If your PCB is lying flat in the bottom of the etch container, the disloved copper will leave a film on your PCB. This effectively acts as a barrier between the PCB and etchant. The answer is to agitate the PCB or as mentioned, use something like a paint brush. Also mentioned is highter temperatures which usually speeds up chemical reactions - sometimes to a mad gallop. :-)

Peter
Shetland Islands. 

[Non-text portions of this message have been removed]

Re: [Homebrew_PCBs] Acid etch time

2012-07-10 by Slavko Kocjancic

I use 1:1:1 and with near Nill agitation and without heating I the pcb 
is etched in les than 2 minutes.
I use HCL 29%, H2O2 31%, and 100% H2O

Dne 10.7.2012 17:53, pi\ufffde Peter:

Show quoted textHide quoted text

> Never tried acid etching myself. This might be worth noting:
> If your PCB is lying flat in the bottom of the etch container, the disloved copper will leave a film on your PCB. This effectively acts as a barrier between the PCB and etchant. The answer is to agitate the PCB or as mentioned, use something like a paint brush. Also mentioned is highter temperatures which usually speeds up chemical reactions - sometimes to a mad gallop. :-)
>
> Peter
> Shetland Islands.
>
> [Non-text portions of this message have been removed]
>

Re: Acid etch time

2012-07-10 by leeleduc

If you want to experiment with different strenghts of Hydrogen Peroxide, here's a list of where to find Hydrochloric Acid and Hydrogen Peroxide in US stores.

Available at Hardware, Building Supply, and Pool Supply stores
Hydrochloric Acid / Muriatic Acid 31%

Available at Grocery stores, Pharmacies
3% Hydrogen Peroxide

Available at Beauty Supply stores
Developer 10 volume or V10 = 3% Hydrogen Peroxide
Developer 20 volume or V20 = 6% Hydrogen Peroxide
Developer 30 volume or V30 = 9% Hydrogen Peroxide
Developer 40 volume or V40 = 12% Hydrogen Peroxide

Available at Pool / Spa supply stores
Baquacil Oxidizer = 27% Hydrogen Peroxide

--- In Homebrew_PCBs@yahoogroups.com, "txtom2" <unknown2@...> wrote:

Show quoted textHide quoted text

>
> I just mixed up some Muriatic Acid and Hydrogen Peroxide (1:2) and tried etching a very small piece of PC board (cleaned and with no mask)to see how long it takes to etch thru (room temp about 75 degrees F). I saw a change in surface color in a couple of minutes, but no etch thru after 15 minutes. I changed the ratio to 2:2 to increase the acid content and after 15 minutes, no further apparent progress. 
> 
> Can someone please tell me what I'm doing wrong ? About how long should it take to etch ??
> 
> Thanks,  Tom
>

Re: Acid etch time

2012-07-10 by Mike

I usually etch in a plastic food storage bin. If the etch is going slowly, I take the bath, board and all, and place it in the microwave for 60 to 120 seconds. Be sure to stay below boiling!! I use a meat thermometer to measure acid bath temp (it does corrode, but slowly) and stick with about 120F, 49C as the max temp. It does speed up quite a bit.

   SAFETY:
 In my microwave oven, the copper plate does not cause arcing but that may not apply to all microwave ovens. DO not let it boil, ore you will have hot acid all over the inside of your microwave! And it may through a few more bubbles as you take it out and the acid bath hits hot parts that weren't covered before.

  When ever I try brushing, I inevitably brush off the mask lines. That may mean my toner transfer technique is poor, but I just stick with non-contact etching to avoid problems.

Mike


--- In Homebrew_PCBs@yahoogroups.com, "txtom2" <unknown2@...> wrote:

Show quoted textHide quoted text

>
> I just mixed up some Muriatic Acid and Hydrogen Peroxide (1:2) and tried etching a very small piece of PC board (cleaned and with no mask)to see how long it takes to etch thru (room temp about 75 degrees F). I saw a change in surface color in a couple of minutes, but no etch thru after 15 minutes. I changed the ratio to 2:2 to increase the acid content and after 15 minutes, no further apparent progress. 
> 
> Can someone please tell me what I'm doing wrong ? About how long should it take to etch ??
> 
> Thanks,  Tom
>

Re: Acid etch time

2012-07-10 by tda7000

No surprises there, you're using H202 up to 10x stronger than most people.

Another guy using 30%: http://milwaukeemakerspace.org/2012/04/pcb-with-lasered-paint-resist-and-fast-sponge-etching/

--- In Homebrew_PCBs@yahoogroups.com, Slavko Kocjancic <eslavko@...> wrote:

Show quoted textHide quoted text

>
> I use 1:1:1 and with near Nill agitation and without heating I the pcb 
> is etched in les than 2 minutes.
> I use HCL 29%, H2O2 31%, and 100% H2O
> 
> Dne 10.7.2012 17:53, pie Peter:
> > Never tried acid etching myself. This might be worth noting:
> > If your PCB is lying flat in the bottom of the etch container, the disloved copper will leave a film on your PCB. This effectively acts as a barrier between the PCB and etchant. The answer is to agitate the PCB or as mentioned, use something like a paint brush. Also mentioned is highter temperatures which usually speeds up chemical reactions - sometimes to a mad gallop. :-)
> >
> > Peter
> > Shetland Islands.
> >
> > [Non-text portions of this message have been removed]
> >
>

Re: [Homebrew_PCBs] Re: Acid etch time

2012-07-11 by Leon Heller

On 10/07/2012 21:10, Mike wrote:
>
> I usually etch in a plastic food storage bin. If the etch is going
> slowly, I take the bath, board and all, and place it in the microwave
> for 60 to 120 seconds. Be sure to stay below boiling!! I use a meat
> thermometer to measure acid bath temp (it does corrode, but slowly) and
> stick with about 120F, 49C as the max temp. It does speed up quite a bit.

I do my etching with FeCl3 in a small plastic food container in an old 
washing up bowl with about 1" of just boiled water in it. With 
continuous agitation etching takes under 5 minutes.

Leon
-- 
Leon Heller
G1HSM

Re: Acid etch time

2012-07-19 by James

--- In Homebrew_PCBs@yahoogroups.com, "txtom2" <unknown2@...> wrote:
>
> I just mixed up some Muriatic Acid and Hydrogen Peroxide (1:2) and tried etching a very small piece of PC board (cleaned and with no mask)to see how long it takes to etch thru (room temp about 75 degrees F). I saw a change in surface color in a couple of minutes, but no etch thru after 15 minutes. I changed the ratio to 2:2 to increase the acid content and after 15 minutes, no further apparent progress. 
> 
> Can someone please tell me what I'm doing wrong ? About how long should it take to etch ??
> 
> Thanks,  Tom
>

Heating the solution makes a huge difference. I use a vertical etching tank I made of plexiglass with an aquarium heater and a bubbler to agitate the solution. PCBs normally finish etching in a few minutes depending on the peroxide concentration. I find that the faster the etch, the less chance of pitting or other damage to areas under the resist.