Quote:
Originally Posted by knc1
Phooy - running out of 35% hydrogen peroxide for the test runs.
Well, I do have 10 days worth of notes to type up and make sense of (before the acid splashes do in the paper and ink).
Want to etch a board in under 20 seconds?
When reference board in MG-415 commercial etchant takes 20 minutes?
The 'key' this time was to use a buffer (C2H4O2) rather than a chelating agent (C6H8O2).
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OK - Made some progress on the notes.
I think I have the chemistry at work cornered, see attached.
I do have the chemistry cornered.
New record: 4 seconds to etch a board vs 20 minutes for the most common, commercial, etchant.
Surprise, surprise, you don't need that H2O2 after all.
Still to do, update observations and conclusions, but the WIP document is attached as of today.
This stuff is old news:
Spoiler:
The molar amounts (ratio) I am using now:
55M H2O2 : 24M HCL : 3M C2H4O2 (55:24:3)
Those are based on observation of timed trials, not on balancing the entire system of equations.
When using these common solutions (% Wt/Wt):
H2O2 (35.00%) - "Food Grade" Hydrogen Peroxide - Health Food Store
HCL (31.45%) - sold as: Muriatic Acid - "Pool Acid" also sold at building supply stores for various uses in the construction trades.
C2H4O2 (99.85%) - Glacial Acidic Acid - (a.k.a: Vingar on steriods) - Probably only available from chemical suppy companies (on-line).
And mixed by volume (because that is easist for the DIY chemist) to make 100ml of etchant:
59.5ml, (35%) H2O2
37.5ml, (31.45%) HCL
3.0ml, (99.85%) C2H4O2
(60:37:3 should be close enough)
Use immediately after mixing - it has a tendency to self-destruct.
Take all required precautions for handling dangerous chemicals.
The acids are corrosive, the products are poisonous.
Beware of splash, splatter, and spillage from boiling.
This solution will generate a lot of heat, even after the copper has been etched from the board (it is a complex set of reactions - they take longer to stabilize than to etch the board).
The large volume of gas being released is hot O2 (oxygen).
Beware of using Nitrile gloves - this stuff attacks nitrile, see:
http://www.ozoneservices.com/articles/004.htm
Edit:
Fixed a typo - I had lost track of a couple of electrons. Shame on me.
Edit:
Adding some more Acetate might help, there are a lot of those H3O ions looking for a home.
See:
http://www.amazon.com/Copper-Acetate...copper+acetate
And for your acid shopping pleasure, see:
http://www.amazon.com/Bottle-Glacial...ds=acetic+acid
Edit: Attachment updated 08/21/15.