Question for DIY PCB people.

[toked323]

I have a question for you people that etch your own board mainly using the acid/peroxide mix.
I was wondering how do you dispose of this, last couple of times i poured it out in my back yard,
unaware that there was copper chloride (which is poisonous). I just read about it. Anyone have any
suggestions for disposing this stuff?

 

[woop]

you could store it in a plastic drum or something, then when its full, take it to a chemical disposal place.
or you could use just a peroxide mix, which should be safe to pour in the garden. (not sure about that though)

 

[pseudolobster]

At the very least I would neutralize the remaining acid with something like baking soda... then I dunno, bring it to a special disposal place (I know the dump takes this stuff for a fee, otherwise I think my recycling depot will dispose it for free)... either that or well, I have a habit of dumping chemicals near train tracks.. since any ground that train tracks have been on is already considered contaminated, I figure I'm not really hurting much...

 

[rkcstr]

You could start using ammonium persulfate (persulphate). It's supposed to etch just as well, but isn't toxic or hazardous, you can dispose down the sink.

As for the HCl/H202, @psuedolobster, the acid isn't the problem, it's the copper chloride which is toxic. I once read a method of chemically reacting to safer compounds for disposal... or like others have said, call around to some local places to ask about disposal. I once also have seen it suggested to try asking a mechanics shop or somewhere that has an oil disposal, if you can dispose your chems there... but I'm not even really sure that's safe?

 

[Bionic-Badger]

If it's copper chloride, can't you just regenerate it and reuse it? Isn't that one of the benefits of using it?

 

[toked323]

If it's copper chloride, can't you just regenerate it and reuse it? Isn't that one of the benefits of using it?

You can reuse it but eventually it will go bad. I just wanted to know if I ever needed to dispose it. I would do the train tracks but bums walk them so, I dont want to harm anyone.

 

[rkcstr]

I haven't tried it, but bubbling air through the solution is supposed to take the place of using the H2O2 to "recharge" it... since you're likely using the 3% solution from a local store, it has a lot of water and tends to dilute the solution making it difficult to effectively regenerate its ability to etch.

What I've been thinking about doing is making an etchant tank out of lexan (or other clear plastic sheet) with a heater and bubble wand for a fish tank.  The bubble want will help to evenly etch the boards (with bubble flowing up over a vertical board) plus will regenerate the solution if I just leave it on for a little while afterward.  Adding some acid or water may be necessary with time, though.

Although, I've used the peroxide recharge and I really don't like how slowly the copper chloride etches alone, so I'm not sure the "recharged" solution would even really work well enough for me.  Either way, though, I think the tank would work a lot better than my plastic tray and manual agitation.

 

[toked323]

I haven't tried it, but bubbling air through the solution is supposed to take the place of using the H2O2 to "recharge" it... since you're likely using the 3% solution from a local store, it has a lot of water and tends to dilute the solution making it difficult to effectively regenerate its ability to etch.

What I've been thinking about doing is making an etchant tank out of lexan (or other clear plastic sheet) with a heater and bubble wand for a fish tank. The bubble want will help to evenly etch the boards (with bubble flowing up over a vertical board) plus will regenerate the solution if I just leave it on for a little while afterward. Adding some acid or water may be necessary with time, though.

Although, I've used the peroxide recharge and I really don't like how slowly the copper chloride etches alone, so I'm not sure the "recharged" solution would even really work well enough for me. Either way, though, I think the tank would work a lot better than my plastic tray and manual agitation.

I know some people who sell those fish tabk bubblers, I bought one for 2$ i can see if theres more if you want and you pay me for it.

 

[JLSE]

I started etching my own boards recently. I found that the air stone trick is more or less used to agitate the solution to speed up the etching and make it etch more evenly. I made an agitator in this way, but then found something a little better. I used an old PS2 controller, and removed the vibration motor. I set this up with some old parts and made an agitator that puts ripples in the fluid and does perfect etching in about 12-15min. Total build time for this was under an hour, done with parts availible from the dollar store and old junk.

These were some of my first boards for a 7135 circuit, dont laugh at the primative hand drawn board :-/

 

[Bionic-Badger]

You should just try recharging the etchant, that way you can reuse it and not even need to dispose of it.

 

[positron]

That looks awesome wannaburn very creative.

One idea that I have read about, using ferric chloride as the etchant. If you use a sponge paint brush (looks like a normal paint brush for painting walls and what not in your house) and gently brush the surface of the board continually, it will etch in 3 mins or so. I really want to try it but I just haven't had the time to do any etching or much of anything fun in ages. Let us know if it works if you end up trying it.

 

[chaosfourever]

Seems like a ton of work