Hi Grant.
How is the copper reaction going ? What color is the acid
solution now ? Can you smell HCl when you put your noise in the
container ?
I'm testing the procedure once again on small scale to get a
better idea. I've got 12.3 grams of 0.7mm copper sheet about half
immersed in 40 ml of 10% HCl, in a beaker. I'll let you know how
it goes. Temperature here is 8°C (night) ~ 17°C (day).
For holding a PCB vertical I use a piece of 20 mm PVC electrical
conduit. I cut a slit length ways into one end of the pipe using
a wood hand saw. I heat the end up so its just a tad soft and
push a piece of PCB material edge on into the slit. Then I
immediately cool under water and it leaves an gap equal to the
PCB width. It seems to make a tight fit with the PCB when cold.
I'm getting a digital camera soon so I'll be able to take some
pictures. Especially of the copper reactions in HCl.
The Rex web page mentions about horizontal etching being much
better in terms of uniformity. I have never tried this method but
I know from experience that vertical bubble etching does not
produce good uniformity. The only disadvantage I can see in
horizontal float etching is it being limited to single sided
action which doubles your etch time. However, horizontal float
etching may produce more aggressive agitation at the copper
surface . I would imagine bubble distribution is critical.
Adam
grantfair2001 wrote:
> Luther - thanks for the hydrogen peroxide idea (and thanks to Rolan
> for this also). I may try it tomorrow since I don't see much change
> after 24 hours with the lid off the etch tank, except a few more blue
> spots; maybe ten 1/4" long bits on the many copper wire above acid
> level. I know someone who is a hairdresser and I think they have
> access to inexpensive hydrogen peroxide so I'll see what concentration
> it is and if its cheaper than drug store grade.
>
> Grant
>
> --- In Homebrew_PCBs@yahoogroups.com, luther m stroud <dukes500@j...>
> wrote:
>
>>I made my cucl like you with copper and hcl . adding some drug store
>>hydrogen peroxide 3% on the bottle will help get it strarted . the data
>>on some graphs i was looking at said etch is best at 35c about 2,5 molar
>>cucl and a saturated with sodium cloride also in that same bath of
>>etchant. allows you to use less hcl. wonder if you can heat the air
>>you bubble to warm the solution rather that cool it . good luck with
>>your etcher project.
>
>
>
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