Five Minute Etching

[Paul Marossy]

Maybe not new news to most here, but I finally tried doing the etchant in a ziplock baggie trick. Filled the kitchen sink with about 2" of straight hot water, placed the baggie in the hot water and agitated it by hand for about five minutes. Totally etched in five minutes with etchant that I have used about six times now! I'm using this method from now on.

FWIW.  

[LeeM]

Maybe not new news to most here, but I finally tried doing the etchant in a ziplock baggie trick. Filled the kitchen sink with about 2" of straight hot water, placed the baggie in the hot water and agitated it by hand for about five minutes. Totally etched in five minutes with etchant that I have used about six times now! I'm using this method from now on.

FWIW.  

whats the Ziplock baggie trick? :?

[RedHouse]

I use a similar process but I use a clear plastic food container I got at Wall-mart for $3, it's about 6"x9" so I can make a fair size board, and it won't get a tear or puncture from the board while etching.
(not that a ziplock won't do just fine, I just decided the container was a more permanent solution for me)

First I pour some ferric chloride in the container and pop it into the microwave for 15-20 seconds, after placing the un-etched PCB into the container it goes into the sink-of-hot-water with the lid on which keeps fumes under control.

I too get the 5-minute result, it's amazing how you can litterally see the copper getting washed away as you rock the container gently (agitate) as it sits on top the hot water bath. Moderate heat really helps the etching process.

Note; the container is actually clear plastic not the semi-opaque white plastic most commonly found. The clear container lets you see your progress as you etch so you can pop the board out when it's done saving you from undermining the etched traces.
(leaving a board in etchant too long, the etchant can eat away at the copper from the sides of the traces getting under the masking material, not a big deal but can be bad if the board uses small/skinny traces)

[toneman]

both exclnt! techniques 4 1off pcbs!!!
why even perf when U can etch??
the "tupperware technique" would allow U 2 store the liquid
after etching was done.
has any1 tried this with muratic acid/H2O2??
stayetched(safely)
tone

[RedHouse]

toneman
both exclnt! techniques 4 1off pcbs!!!
why even perf when U can etch??

Exactly!

[MartyB]

Working with biologicals back in the '80's taught me that trick.  It works great - much neater, more efficient, less etchant!  The snack size bags are perfect for most pedal pcbs.  I think my previous posts on this were in the old forum.  PM me if you want more details.
MartyB

[Paul Marossy]

Well, I'm glad that someone didn't know about the ziplock baggie trick. I guess I should add that I gently agitate the baggie, so I don't damage the baggie or anything.  

[The Tone God]

I use a cheap plastic tupperware-like container. Drop the board in with the etchant then float the container in a work tub/sink (not one used for food preperation) filled with hot water. I can agatate the board and if any etchant overflows it lands in the water and quickly dilutes. The hot water heats up the solution to increase etching time. I can reuse the container. I bought it at a one-dollar type store. You could also use a container from some kind of food spread like margarine or cheese.

My biggest concern with bags would them breaking.

Andrew

[Paul Marossy]

Yeah, a scapegoat tupperware kind of thing is probably better suited for this application. In any case, it works well! The heat along with the agitation makes quick work of it.  

[The Tone God]

The heat along with the agitation makes quick work of it.  

For every 10 degrees celsius increase in tempature the speed of the ferric chloride doubles so get that stuff as hot as possible before fumes and other bad stuff happens. Usually the tempature of the hot water out of the tap is good.

I mention this for newbies reading this thread so they don't just throw boards into cold etch doing nothing and come back later to see not much happening.

Andrew

[Paul Marossy]

I mention this for newbies reading this thread so they don't just throw boards into cold etch doing nothing and come back later to see not much happening.

Yeah, I remember the first PCB I ever etched took 45 minutes or so.  :shock:  I didn't heat up the etchant at all, but I was periodically agitating it a little bit.

For every 10 degrees celsius increase in tempature the speed of the ferric chloride doubles

I did not know that. Interesting...

[ErikMiller]

For people who haven't tried this, the "freezer" type of zip-close bags are made from heavier plastic.

Also, I use ammonium persulphate or sodium persulphate etchant. Safer and less messy.

[Paul Marossy]

Doh! I forgot to mention that it was a freezer type ziplock baggie that I used.  :oops:  As noted, they are thicker...

[David]

both exclnt! techniques 4 1off pcbs!!!
why even perf when U can etch??
the "tupperware technique" would allow U 2 store the liquid
after etching was done.
has any1 tried this with muratic acid/H2O2??
stayetched(safely)
tone

Somebody's going to a little later on!   :twisted:  :twisted:

[Brian Marshall]

dont put etchant in the microwave.... even if its sealed.

microwaves  heat individual moleules when the "microwaves" hit them (they dont really use microwaves.  this causes molecular dispursion... even if it doesnt get close to boiling it will at least slightly contaminate your microwave....   i wouldnt even use it anywhere in the kitchen.

[toneman]

*usually*, the rule 4 microwaves is--
"no metalic objects"

FeLC3, or IronChloride has iron...a metal!!

Oh Kay, it's not heavy metal....like lead...heh heh
...or Pantera... 4 that matter...

best way (only way) to heat it, is in an indirect water bath.
with the "tuperware technique", U could seal the tupperware,
and immerse it in a sink of hot water 4 a while.
plastic (tuperware) doesn't conduct heat very well,
so U can leave it in 4 a while.
MayB U could leave in it the sun on a black pad(?)
This would probably work 4 the acid/peroxide technique 2.
But, i would say, just heat up the acid.
Then when at sufficient temp, *then* add the H2O2.

Just!! Bsure!!! not to do the etching in the sink!!!
Messy messy messy...stains..fumes....etc etc.
After solution is warmed, take it outside to do the etching.
Disposal of the small quantity of etchant can B done by using
it as weed killer...FeCl3 is used in Water Treatment plants
to remove metalic contaminants.  Then IT is removed as sludge.
stayetched(more than one way)
tone

[RedHouse]

(start of rant)...

Nope, that's all a bunch of BS, just extrapolation by psuedo-logic.

Put it in the microwave ...WITH THE LID ON... you will get no leakage or contamination WHATSOEVER, I've been doing this for a few years now with absolutely ZERO effect on the microwave.
(sorry Brian)

Put it in the sink 1/2 filled with some hot water, again ...WITH THE LID ON... no mess, no leakage, no contamination. I've been doing this for a few years now with absolutely ZERO effect on the KITCHEN sink.
(sorry Toneman)

Sheesh!  :roll:  ...(end of rant)

Anyway, I used to use old Tupperware but it's not clear and you have to open the lid and check your progress fairly often because it works so much faster heated, each time you open it, it which looses heat and fumes and only slows down the process, with the clear plastic container (can't recall the brand) you only open it when you are done. All fumes and heat stay withing the container completely during the 5-minute etching cycle.

In my case, the hot water is not for heating the etchant in the container, it's for keeping the etchant hot (which was heated previously in the microwave).

Here's another tip for noob's, after etching when you remove your mask material (toner, photomask, rub-on, whatever) you should clean the copper of all traces of etchant, this is usually done by rinsing with a 5% tincture of HCL acid (aka muratic) but the home DIY'er can successfully use fill strength white vinegar, yep, vinegar.

Etchant is an alkali and is removed with an acid rinse, after rinsing the board in water, place it in a shallow tupperware container, pour in 1/4" of vinegar, and scrub with an old toothbrush, rinse in water and repeat.
(use same vinegar though)

Cleaning after etching ensures your copper traces don't turn green/blue after a while, and more importantly it gets all etchant off the copper. Without cleaning, even if one might apply solder over the traces immediately after etching, some etchant residue stayes on the sides of the traces and keeps working, you can make boards that have crappy copper under the solder, look good from the top, but crap under the solder, and it can even effect the circuit when circuit traces are thin.

[Paul Marossy]

extrapolation by psuedo-logic

Whoa! Them is some big words there...  :wink:

[RedHouse]

Yea, guess I better stop watching the Discovery Channel :wink:

[Paul Marossy]

LOL.  :lol: