easier - cheaper -Etching OF PCB's! With Ferric Chloride.

[davepedals]

i know a lot of folks spend good money and time building agitation tanks with heaters to etch pcb's. 
i found what is IMO a better/faster/cheaper method! -  not my idea, i found it here:
http://www.instructables.com/id/Sponge-Ferric-Chloride-Method-Etch-Circuit-Bo/

it helps to warm up the solvent with a hairdryer, but really... using this "sponge" method has saved me a lot of $$ on ferric chloride as you can use a tiny amount in a bowl for "fresh dipping."  basically you dip the sponge in the solvent then wipe (i prefer circular motions) the PCB's surface.

keeping firm (but no motion) contact for a few seconds on trouble spots works wonders! i can etch a 4" x 4" pcb in about one minute using maybe three cap-fulls of ferric chloride, and normally i can add a 2nd board to the leftover chloride and etch yet another with perhaps only an additional cap-full of fresh chloride!  save time, save money!  again - i take NO credit here....... read this guys tip! it works great!
http://www.instructables.com/id/Sponge-Ferric-Chloride-Method-Etch-Circuit-Bo/

[Perrow]

Search Google for contact etching, it's been discussed here before too.

[Keeb]

Search Google for contact etching, it's been discussed here before too.

A bit off topic here but... As a fellow Swede, do you know where I can find ferric chloride in Sweden?
Currently I'm using sodium persulfate (kjell.com or musikding) which works but I want to etch enclosures as well...

[Perrow]

Search Google for contact etching, it's been discussed here before too.

A bit off topic here but... As a fellow Swede, do you know where I can find ferric chloride in Sweden?
Currently I'm using sodium persulfate (kjell.com or musikding) which works but I want to etch enclosures as well...

Craft stores (i.e. Konstnärsaffärer/måleriaffärer). For example:

http://www.ibwahlstrom.se

They solid solid FE in 1kg jars or liquid in 36kg jars  $480 USD  The 1kg solid is about $20 (156kr) though.

I haven't tried FE yet, still using sodium persulfate from Kjell, and I don't etch that much so I can wait for 20 min when I etch. I mix up about one deciliter each time and etch at least four or five boards on that. Cost isn't really an issue, I spend more on PCB drills.

[kodiakklub]

+1 on the sponge method. i never did the soak-in-tray method. I havent tried heating it up yet, but at room temp it takes about 6-8mins for a 2 x 2 board. and you need to keep using new areas of the sponge every minute or so.

[Earthscum]

I extend my etchant using the sponge (I actually use blue disposable shop towels) when the etchant starts wearing out. I'll just let the gunk settle to the bottom and skim the FeCl off the top. It's also a useful way to dispose of it slowly without having to figure out what to do with a container of nasty liquid.

For me, if I'm not extending use then it depends on what I'm etching. If I have something with fat traces, I'll just let it soak at work while I screen print. If it's something with thin traces, or lots of traces, I'll do a soak until the board just starts to peek through, then I'll finish it off with the wiping method. That lets me control the undercutting, and I can manually keep traces fairly consistent.

[asatbluesboy]

That's a pretty neat trick. Definitely gonna try that. My Ferric Chloride is about 5 years old and won't etch that well anymore...

Yes, I am lazy -and- cheap. And I live in a small town where you can't really find Ferric Chloride to save your life.

[SISKO]

I could never make this work out as I expected. It always eat away my etch resistant/toner. Maybe Im aplying too much preassure?

[Earthscum]

I could never make this work out as I expected. It always eat away my etch resistant/toner. Maybe Im aplying too much preassure?

Most likely yes, but it may also be that your toner has a weak bond with the copper. If you have a good system down and it works with soak method etching, then it's probably just the toner. I use an OKI C6150 here at work and it seems to take fairly well.

When I do this method, I am pretty much keeping the surface soaked, move to another area and clean the dead material away with FeCl, let it soak while I work on another area. Wet sponge, just rub the area enough to get the black off and the copper will start to get shiny, then you can move your way around. When it's all looking good, I'll get things wet once more and do a heavy "scrub", which usually takes some of the toner off, then rinse before it has a chance to start oxidizing the traces too bad.

[deadastronaut]

i'm lazy, i just lob them in, make a cuppa, talk to (annoy) the cat, have a pee, done!...

i always use fresh ferric for etching boxes though, and then bottle it up and  re-use it for pcbs only.

[arma61]

I've found that leaving the board suspended, facind down, floating on the acid, is time saving, ~15/30% of time, I think I've seen Mark Hammer (not sure, but surely in this forum) using some toothpicks at the 4 cornes to keep the board suspended, works very good.

Ciao

[J0K3RX]

+1 for the sponge method and I heat Ferric Chloride in the microwave for about 10 sec... Etches fast!

[Zipslack]

I'll give you one that 's cleaner/neater than the sponge and still uses little etchant - ziploc bags.  I have assorted size parts bags, pick one that will hold the board.  Put in 1-2 teaspoons of etchant.  Seal.  Shake, roll, rub, agitate, whatever...  Works quickly and efficiently and without wasting lots of etchant and getting all over the place by sponging.  When ready to rinse, open the bag and dilute with water.