Homebrew PCBs

He's not less HCl,  he's just using more pure hydrogen peroxide -- which
also means less water.

Heating the solution with an aquarium heater, and having a bubbler float
bubbles by the board both speed things up. Be aware that the higher
temperatures can increase the fumes -- and you do NOT want to inhale these.
 The bubbles can also a) be rougher on your etch resist and b) increase
undercutting.  I saw the last point in a white paper somewhere,although I
can't seem to find the reference now though.

Sent from my iPad

On 2011-11-27, at 9:38 AM, DaveC <davec2468@...> wrote:



>31% HCL, also known as Muriatic Acid. A standard strength I buy at
>just about any hardware/building supply store. Also available at
>pool supply stores.

I'm using the same effective ratio. My muriatic is 15% and h2o2 is 3%
and my ratio is 1:1.This is the same as you're using: 31% hcl and 3%
h2o2 at a ratio of 1:2.

I'm still not sure why my etching takes so long.

> > >I've also tried 1 part HCL and 2 parts 12% H2O2 but the reaction was
>> >too fast and hot to control easily.

I'm confused: you use LESS hcl and the reaction was faster? I thought
the acid is what increased (using more) or decreased (using less) the
speed of the reaction, no?

Thanks,
Dave

-=-=-=-

>--- In Homebrew_PCBs@yahoogroups.com, DaveC <davec2468@...> wrote:
>>
>> What strength hcl are you using? The ratio is easily understood, but
>> it all depends on the strengths. (I see you use 3 percent h2o2.)
>>
>> Thanks
>> Dave
>>
>> -=-=-=-
>>
>> >I use this technique all the time. I can do a 4X6 inch board in
>> >about 2 minutes. I use 1 Part 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.
>> >
> > >I've also tried 1 part HCL and 2 parts 12% H2O2 but the reaction was
>> >too fast and hot to control easily.
> > >
>> >
>> >
>> >--- In Homebrew_PCBs@yahoogroups.com, "tda7000" <Tda7000@> wrote:
>> >>
>> >> I see some people get very fast etch times with a sponge and
>> >>ferric chloride...
>> >>
>> >> But has anyone tried that method with the HCl and H2O2 solution,
>> >>or the cupric chloride?
>> >>
> > > > Or anything else for that matter?
 


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