Giant Hogweed Octave Distortion

[Timko]

I finished the last of my "birthday builds" from November.  This one is Rolo's octave circuit.  I've built 4 other octaves (the Octavia and the Foxx tone from madbean, a Purple Platapus, and a custom octave up/down with a Big Muff), and this one really suits me the best.  The Roger Meyer Mongoose circuit has a lot of sounds, from splatty, compressed fuzz to a mild overdrive and everything in between.  I've not built any LM308 circuits yet, but that IC has a nastiness not present in any other fuzz I've built.  The controls for the octaves are really simple to dial in too; the custom octave muff I did had 2 additional knobs.  The etch turned out pretty well too; the more I use muriatic acid, the happier I am with the results.

[flanagan0718]

Great build! I love the enclosure. Is that an etch or a water slide?


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[Timko]

It's an etch. It took me a while to find a picture that would make a good mask for the etch.

[stringsthings]

That's a very good etch.

Do you mix the muriatic acid with hydrogen peroxide?

[m-Kresol]

didn't you get the memo: it's gAInt hogweed now 

turned out great!

Do you mix the muriatic acid with hydrogen peroxide?

I said it lots of times before and I'll say it again. DO NOT DO THIS. The mixture will form chlorine gas, which is toxic, gives you lung oedema and stuff. It should only be handled in proper fume hoods by professionals. There's more safe and less aggressive etchants out there, which makes using any other an unnecessary risk! Use ferric chloride, NaOH or muriatic acid, but the later two will also need proper ventilation, especially HCl because the fumes are also corrosive and should not be breathed in!

[drolo]

This looks absolutely stunning :-)

[bcalla]

Beautiful!

[Timko]

Do you mix the muriatic acid with hydrogen peroxide?

I said it lots of times before and I'll say it again. DO NOT DO THIS. The mixture will form chlorine gas, which is toxic, gives you lung oedema and stuff. It should only be handled in proper fume hoods by professionals. There's more safe and less aggressive etchants out there, which makes using any other an unnecessary risk! Use ferric chloride, NaOH or muriatic acid, but the later two will also need proper ventilation, especially HCl because the fumes are also corrosive and should not be breathed in!

+1.  I use a ventilator because my basement has marginal ventilation.  But an absolute DO NOT is to mix muriatic acid and peroxide.  I had a long conversation with a friend who teaches high school chemistry about this, and trust me, it's bad news bears.

[stringsthings]

With all due respect, I tend to disagree.

https://www.cs.uaf.edu/2007/fall/cs441/lecture/10_11_pcb.html

[Timko]

Acid Magic does not need anything added to it.  And as someone who did etches with Ferric acid for a long time, Acid Magic works in 1/4 of the time with much cleaner lines.

[alanp]

Felix has letters after his name in the field of chemistry. If it's pertaining to a chemical reaction, I'm inclined to believe him.

[m-Kresol]

With all due respect, I tend to disagree.

https://www.cs.uaf.edu/2007/fall/cs441/lecture/10_11_pcb.html

It does work of course, but I find it unnecessarily dangerous for the task. There are better options out there and safety should always be top priority. The tutorial you linked also seems to be by someone with a PhD, so I can't really argue there, but again, there's more than one way to do it.

Also, I have to admit that there was a language problem too. I assumed that muriatic acid was synonymous with hydrochloric acid, which it is, but muriatic acid also usually means a less concentrated form, which is not giving of that many fumes. Furthermore, I thought that the H2O2 solution was more than 3% (we generally use 20). This, of course, makes the progress a lot less dangerous, because everything is way more dilute and less reactive.

That being said, most of the people who use FeCl3 after going the acid/acid+peroxide route first have better results, it's just a bit less aggressive to the toner (might be because FeCl3 is a Lewis acid, whil HCl is a Brønsted acid. Just so we get some science going )

Sorry for the thread-derail Timko

[Timko]

That's fine; I'm asking 2 chemistry majors (and teachers) right now for the chemical conversion equations.  The chemical reaction could produce considerably less gas at 3% than 20%.  Once they give me the limiting reagent we'll know.

[m-Kresol]

I can give you that too. It's a simple redox reaction, with peroxide (being an oxidizer) being reduced and chloride being oxidized to chlorine.

2 HCl + H2O2 -> 2 H2O + Cl2

Both components can be limiting, that solely depends on their concentrations and the amount of solution used. But yes, a 3% peroxide solution will certainly give a much less pronounced reaction and most likely be the limiting component unless you use 1 ml of acid and add 1 l of peroxide solution.

[Timko]

Madbeans forums: a place for all sciences.