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Subject: Re: [Homebrew_PCBs] Re: CuCl etchant - an update

From: Harvey White <madyn@...>
Date: 2013-09-04

On Tue, 3 Sep 2013 20:32:13 -0400, you wrote:

>Harvey,
>I'm in Tampa
> looks like were almost neighbors. :)

My Mother in Law lives in Sun City Center, we were down there
yesterday.

>Mine seems to settle in around olive green. Ive never seen any blue to speak of.

The blue is as it is just starting off, once it's CuCl, it's olive.

>my ingredients are: CVS or Walgreens Hydrogen peroxide, and good ole Home depot Muratic acid sold in 1 gallon jugs.
>my results are always the same. I have heard of people getting etch times in the sub 10 mins I have never had one etch that fast.
>perhaps they are using 1/2 oz frp boards? 6 mins vs my 13 is about 1:2 ratio.

I think they are using the 1/2 oz boards rather than the 1 oz boards.
>
>My bubbler works extraordinarily well. my tank has the heat option but As i said earlier I get the same results either way.
>
>I think the weakest link with my setup is I have yet to find a way to hold the boards perfectly vertical so they etch the same on both sides
>one side always etches faster than the other (the side getting more bubbles)
>

That or you take the board out and rotate it 180 and put it back in. I
have top to bottom etch disparities depending on the bubbler (what do
you use for a distributor? I use a piece of irrigation fitting
drilled to match, but it has to be level to work well).

Since I only do single sided etching (and then epoxy the boards
together) I only worry about top to bottom. It works better with
toner transfer, but I suspect you are using photosensitive material.
There are tricks to doing double sided toner transfer on a double
sided board, but the epoxy method works well enough for me.

try www.dragonworks.info not been updated in years, but it shows a
few things.

Harvey

>Sam
>
>
>
>
>
>
>On Sep 3, 2013, at 8:06 PM, Harvey White <madyn@...> wrote:
>
>> On Tue, 03 Sep 2013 23:51:48 -0000, you wrote:
>>
>> >Forgot to mention.
>> >
>> >here is what mine looked like.
>> >http://thesn1per.blogspot.com/2013/06/diy-circuit-boards-tachometer.html
>> >
>> >The color you see is the result after about 1 hour of mixing with a small piece of coper
>> >bubbling the entire time. I used no heat. Im in Florida the ambient temp is quite hot as it is.
>> >I tried heat on previous times the results ere the same.
>> >I will add as time goes on the mixture will become a darker shade of green.
>> >I hope this helps.
>>
>> Hmmmm. Ok. As I first started it, peroxide and HCl, the mixture was
>> transparent and colorless. Boards etched in about 6 minutes or so (I
>> did have air bubbling through and did heat the solution).
>>
>> As the solution aged, it turned blue/green, not the same shade of
>> green you show here.
>>
>> As it aged past that, it turned a dark green, almost opaque, a slight
>> shade of olive green.
>>
>> Air is used to bubble through the solution as it heats, and is used
>> continually as the solution etches. I use heat anyway, and the
>> temperature is about 110 or so F, it could get to 120 but I'm not sure
>> you want it hotter than that.
>>
>> I used the copper in the boards to make the CuCl etchant, no sense in
>> wasting the peroxide dissolving unwanted copper.
>>
>> Not sure what the problem is with what you have, but the color seems
>> to be off. You should get the standard blue copper sulfate kind of
>> color to start with.
>>
>> With the olive solution (if it turns brown, it's off), adding peroxide
>> can change it to a blue transparent solution.
>>
>> You near Orlando?
>>
>> Harvey
>>
>> >Sam
>> >
>> >
>> >
>> >
>> >
>> >--- In Homebrew_PCBs@yahoogroups.com, "thesn1per" <mail4sam@...> wrote:
>> >>
>> >> Pink? should be green or some shade of.
>> >> Sam
>> >>
>> >> Read this.
>> >> http://members.optusnet.com.au/~eseychell/PCB/etching_CuCl/
>> >>
>> >>
>> >>
>> >>
>> >> --- In Homebrew_PCBs@yahoogroups.com, <twgray2007@> wrote:
>> >> >
>> >> > OK, I tried bubbling air through the mixture for about 24 hours with no change. I heated to about 40 C and placed a PCB in just to test and after about 25 minutes it had just started to turn pink from etching. The volume was at about 1/2 gallon and to this I added about 1/2 cup of HCL and left the board in for another 30 minutes with little change.
>> >> >
>> >> > I think I will now put a lot of copper wire in, at 40 C and let it run to see if it will "take off", as you put it.
>> >> >
>> >>
>>
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