Etching Tank - Build your own

[Jdansti]

>solutions. Honestly, the FeCl scares me a bit, the muriatic + peroxyde scares me less...

HCl produces a lot of fumes (pure HCl is a gas at standard temperature and pressure)-not good for the lungs, mucous membranes or CodeMonk's drill press!  HCl and H₂O₂ (H₂O₂ at concentrations stronger than what we use for first aid) will both burn the holy bageezes out of you!!  I haven't been burned by FeCl₃ if I got a little on me and quickly washed it off. A tiny drop of HCl burns on the way to the water faucet.

>Wouldn't there be a way to separate the copper from the solution after reducing its PH with (for example) baking powder ?

I was thinking the same thing about the baking soda (not baking powder ).  Baking soda is not as strong a base as NaOH or KOH, but it should still work:

2NaHCO₃ + CuCl₂ ---> CuCO₃ + 2NaCl + CO2 + H2O. CuCO₃ would precipitate and could be filtered out.  Since the CuCO₃ is still a salt, it's best not to dispose of it down the sink.

Another option is to add Al or Mg.  This would cause the Cu²⁺ ions to form elemental Cu along with Al/Mg salts, which could all be safely disposed in the sink.

3CuCl₂ + 2Al ---> 2AlCl₃ + 3Cu

CuCl₂ + Mg --> MgCl₂ + Cu

[davent]

Washing soda (sodium carbonate) is a more economical alternative to baking soda (sodium bicarbonate). And if you need baking powder you can make your own using baking soda and cream of tartar.

All these neutalizer have been aimed at use with the spent ferric chloride, are they equally suitable for use with the acid/peroxide etchant?

[Jdansti]

They would also neutralize HCl. As for the peroxide, to be conservative, you could assume no decomposition during the etching process or acid neutralization, and estimate the amount of water that you'd have to add to the solution to dilute it below 3%, which is the concentration used for first aid. At that point, it could be flushed down the drain or you could add it to some spent coffee grounds to allow the extra oxygen atom to react with the organic material in the grounds leaving behind water (H₂O).

[davent]

Thanks for the info John!
(Gotta save the coffee grounds for the garden.)

[defaced]

You guys are obviously better at Chemistry than I, but isn't Hydrogen Peroxide pretty unstable, meaning, if you just let it sit, it decomposes on it's own?  I seem to also recall it being photo reactive, hence the brown bottle. 

[Jdansti]

^Yep. It just depends on how long you want to wait for it to convert back to H₂O. Another factor is how to tell when it's inactive. Reacting it with an organic material gives off bubbles that you can see. You know that the peroxide is spent when it stops bubbling.  You've probably seen this if you've ever poured peroxide on a wound. It's oxidizing the carbon based body tissues and blood along with the germs. That gives me another idea: a person could poke a hole in a blood vessel and drain some blood into the peroxide to neutralize it.

My preference would be to dilute it to avoid any immediate reactions, and then let it peter out on its own in the sewer line. After all, there's plenty of organic materials in the sewer to neutralize peroxide.

[greaser_au]

There really are better ways for gluing plexiglass (cast acrylic/perspex/lexan); 
RTV silicone lacks the shear strength for the flexibility that perspex has (It's quite ok for glass as it is quite rigid).
Hot melt glue is fine in cooler climates, but once you exceed about 35 degrees (not at all unusual in summer down under) it tends to move a bit and will let go pretty easily.

Suitable adhesives:  solvent-only (chloroform or dichloromethane) if you can cut & file straight,  or a solvent plus filler if your hand tool skills are less perfect...

IPS manufacture the Weld-On range for our US friends, and down under look up Acrylic Technologies Australia. 

david

[CodeMonk]

First part of this post is on topic, but the second part is off topic.
(Aron, if you want to delete, move, or edit this post, go for it).

The On Topic stuff....
My newest etching tank:
Those airstones work GREAT.
I gotta give a BIG THANK YOU to killerkev for that idea.
Pretty much cuts the etching time in half compared to my previous tank did.
The black bits were cut from a rubber pad that came from a horse trailer.
The white stuff is latex caulking to fill in the gaps.
The whiter bits I just put on today. The yellow parts of the caulking is what it looked like after etching a few boards.



And my drill press:
I paid $50 via Craigslist. It was brand new, never used. The same press is about $80 or $90 from Harbor Freight
That magnifying glass is a god send and I can adjust it on all 3 axis's, and tilt it as needed.
On the far right is my vise. The thing in the vise is insulation from a semi truck trailer (The kind that hauls cold stuff).
It lets me set the PCB level and near the top of the vise and has almost zero resistance to the drill. But it feels as though it will dull the drill bit a bit



Now for the off topic stuff
Perhaps some of you have heard about the Rim fire near Yosemite.
Well, lucky me, I live right in the center of the smoke plume from that fire, just east of that angled area of the California/Nevada border.
Somewhere in that red circle.
Although I'm actually a few hundred miles from the fire.
NASA photo from August 22 or 23:



Here is a pic I took the same day as the NASA pic




Today:




This is normal (A few months old):

[Jdansti]

Sorry to hear that. I've been in smoke plumes from Texas wildfires, and intentional agricultural fires from Louisiana and Central America. It can be a real bummer!

[armdnrdy]

Hey Rob,

I saw that little red circle that you live in......that's not Sparks Nevada is it?

Right over by Pyramid Lake....home of the Lahontan Cutthroat trout.

Do you ever trade that E-335 for a fishing rod for the day?

[CodeMonk]

Hey Rob,

I saw that little red circle that you live in......that's not Sparks Nevada is it?

Right over by Pyramid Lake....home of the Lahontan Cutthroat trout.

Do you ever trade that E-335 for a fishing rod for the day?

Sparks is probably in that area yeah.
I'm in Stagecoach, about 60 miles from Sparks. Roughly 30 miles from Fernley, 30 from Carson City.
I've live in Sparks before, right near Reed High School, another time off of Rock just south of hwy 80.