Homebrew PCBs

>Anything with dissolved copper should not be dumped down the drain, at 
>least if you live in a coastal area like I do where the water eventually 
>ends up in the ocean. 

     The problem with the copper is more likely at the sewage treatment 
plant, for the same reasons that used photographic fixer (silver ions) is 
something they'd rather not have going down the drain. Those metal ions 
kill off the microorganisms (and not so micro) they use to digest the 
sewage. The tour through the hyperion in Huntington Beach many years ago 
was quite interesting.


     I've been waiting for someone else to point this out but haven't 
seen it yet, so...

*******
     DO NOT store HCl/H2O2 (hydrochloric/muriatic acid and hydrogen 
peroxide) etchant in sealed glass bottles. As the peroxide decomposes it 
produces oxygen gas and the resulting pressuure can cause the bottle to 
burst. The pressure can also cause an acid spray when you open it, not 
good for the eyes.
*******

     I like to use the brown plastic bottles that drugstore ~3% peroxide 
comes in, I don't fill them more than half full and I squeeze them before 
capping so there's plenty of room for expansion. Still, I've seen them 
bulge and show a line up the side where the pressure has stretched and 
nearly burst the bottle.

     Seems to me that the "40 Volume" on the higher concentration 
peroxide bottles means it will decompose to 40x it's liquid volume as 
gas. If that's correct, then one cubic inch (unit) will become 40 cubic 
inches (units) of gas while you're not looking.

     Leave plenty of room for expansion, store the bottle in another 
larger container, and just because it hasn't happened to you yet doesn't 
mean it won't happen twenty minutes from now.

     -Gary