Homebrew PCBs

Disposal note...

I had to say we are wery 'eco friendly'.
I etch my board with Hcl and H2O2. For 10x10cm board I use aprox 5ml of 
H2O(tap water), 1ml of HCl(30%) and 1ml of H2O2(30%).

So aprox 2 to 3 years I need to buy new bootle (1 liter) of both.

Now look to disposal problem.

The average household drain HCl in sinks/toilets as cleaner(near all 
cleaner use HCl) in amount much larger that mine is. The quantity is so 
smal so if someone throu up (maybe to much beer) the HCl pollution is 
bigger. So I don't care and throw that into sink. The other content 
H2O2. You may look in two sides. The all hair paint use H2O2 in large 
quantity and throw that stuff into sink directly. Every unnatural 
blondie use much more H2O2 than I. In the other way if we let H2O2 on 
sun few day they completly disentigrate into H2O and O2. So I can say 
that source chemical used is so small that we can just sink em. ..and 
use a loot of watter to dilute it. The worst contaminant is byproduct 
CuCl. And again. The content is so small and we can throw it. The 
average wineagre yard near me use so much CuCl so my quantity is way way 
lower. And someone will say that all that sink output goes into sea. 
CuCl is extensively used to paint boat's to prevent algae sticking on it.


But if you think that we must be the 1'st one to preserve planet then 
you have simple solution how you can dispose the used solution.
Just get one glass jar as low and flat as you can. Put it onto sun and 
pour all chemicals used from pcb etchng into it. Then cover it with 
glass plate little raised. So all thing will evaporate on sun and leave 
the worst (CuCl) as little blue/green sand. When you collect much of 
that than just dispose that in chemichal dispossing containers. But for 
100grams you need to etch a lot of boards.(years)

...But this work's just if you use smallest quantity possible. I see a 
lot of folks use just to much etchant. If you check youtube you can see 
that a lot of users use so big quantity of etchant. So the key is smal 
quantity and smal bath. I use the plastic kontainers for food / ice 
cream. It should have flat bottom and be just right size. (I have 4 
different size) So just use smalest one and use as little etchant as I 
can. ..just to cover the PCB not more. And etch it outside with wind 
blowing in you back. When etching the small content of chlorine gas is 
developed. You don't want to breath that. The etching time is 2 to 3 
minute. And use cold watter. As reaction is exotermic (release heat) the 
solution wil heat up itself. If you use hot watter in start the solution 
will boil when etching and that exesive heat may destroy your image etched.

Thanks for reading and sorry for my ugly english.