Filtering etchant sludge?

[MR COFFEE]

Anyone tried filtering Ferric Chloride after several boards have been etched to get the sludge out?

Does it help? How have you tried filtering it? Will it extend the usefulness of the etchant?

Any links I've missed?

[the dude]

I was thinking about it but have not tried it yet, I was thinking maybe using a coffee filter.

[zjokka]

There is an advantage to FeCl especially to us diystompboxers, because it's very POTENT and RE-USABLE. I mostly use a chloric acide + hydrogen peroxide + water as this is clean, doesn't give sludge and can be poured down the drain when properly diluted. But if you premix this recipe, it won't work a few weeks later. A small bottle of FeCl however will last you a long time etching both boards and enclosures.

Removing the sludge won't extend the life of the FeCl I am very much convinced.

zj

[markm]

IMO, filtering isn't really worth the effort or resulting mess......it's certainly cheap enough to buy more in most locations, not all though as I understand it.

[MR COFFEE]

Thanks for the thoughts guys.

Doesn't sound as promising as I'd hoped.

[Mark Hammer]

Filtering, maybe not, but sludge-less transfer, yes.

If your etchant is, or can be, situated in a tall slender container (e.g., a former pickle or coffee jar), then leave it sit for a while so you get a nice thick sediment/sludge, and gently pour the liquid from the top into a second glass container.  You can then pour in some baking soda or whatever you do to disable the sludge, and properly dispose of it.  Meanwhile, what you have transferred, with a wee bit of water added to it, will easily do you for a whole batch of etches.  Keep in mind that what is "used up" turns into the sludge, and what remains in solution is still reasonably viable.

[markm]

I highly reccommend the Jar method for etching boards.
Just hang 'em in there with fishing line and let 'em etch!
Works very well indeed!

[Hiwatt25]

I highly reccommend the Jar method for etching boards.
Just hang 'em in there with fishing line and let 'em etch!
Works very well indeed!

The jar and fishing line is a good choice if you want to go the sane/inexpensive/smart route.  Me, I love gadgets and I needed one that does just one thing...it shakes PCBs while they sit in baths of etchant.  .  I mean, why let gravity do all the work when people have found a harder way of doing things.  Ahhh, impractical.  It does work well though.


 

[ambulancevoice]

MR. RADAR sir

hehe

wow, that shaker thing is a good idea

[MR COFFEE]

Thanks for the feedback, Mark.

My etching rig is, in fact, tall and I didn't know if it was just aesthetics or OCD but I feel a lot better about etching another board in a tank that doesn't look all nasty in the bottom.

Sounds like I should try decanting the liquid off the top, clean the tank, and pour it back in - forget the filtering step.

Hey that shaker table looks cool!

I'd been thinking about just shaking the PCB ! Now THAT'S the premium solution

Other ideas always welcome.