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No more Ferric Chloride

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Chilli

New Member
I've noticed many people still use Ferric chloride to etch their PCBoards.

Try this one: 200ml HCL 32% + 30ml Hydrogenperoxide(H2O2 30%) + 770ml Water

USE WITH GREAT CARE!!!!!!
Use eye protection!!
Do not store in air tight containers. Use it at own Risk!!

Etching with this solution takes about 60 seconds (depending on the board size obviously)


Chilli
 

Chippie

Member
I use ferric chloride basically coz its cheaper and easier to obtain than Hydrochloric acid.......Hydrogen Peroxide, from a chemist...


Yes its quicker but its a little dangerous......the acid causes burns and the peroxide is an oxidising agent.......flammable to explosive....!!!

I'll stick with ferric......... :lol:
 

spuffock

Member
Ferric chloride is on offer at 7.99 british pounds for 250g. A good proportion of that is water. When you dissolve it in water a fair amount of it turns straight to rust, which forms a sludge and stops the etchant reaching the board easily, and also prevents you seeing what is going on. When you dispose of used etchant it will stain everything it comes near wtth rust. On the whole I couldnt do better to discourage anyone from making their own boards if I was paid. :x

If anyone knows where I can get Ammonium Persulphate in England please let me know!
 

Chippie

Member
Spuffock,

If you consider the price you stated as a bargain, I'd be looking elsewhere.........I'd say it was expensive...... :?


I buy it at 2.5kg a time for less than £10 a time + VAT.......
 

spuffock

Member
the stuff's muck. It wouldnt be a bargain if I was paid to take it away. After the expense of hydrochloric acid and scouring pads to get the rust stains off everything, its cheaper to get the local pcb house to etch it. :x
 

panic mode

Well-Known Member
oh boy.. what are you guys so etching? something in huge quantities
like on industrial scale or what? I am still using the same 0.5L of
ferric chloride I bought ca three years ago. It still works fine after some
200 boards but the etching process is noticably slower than first
time I used it. Big deal, I can always do something else like prepare
all parts etc while etching is in progress.
I just keep it in plastic bottle (and yes, there is some rust at the bottom),
which I warm up with bucket of hot watter (I dip closed ferric bottle
in hot watter for few minutes).
Once warmed up I pour the ferric chloride in plastic bowl and place PCB
close to the surface - when etching single sided PCBs, I even let the
board float (with copper side down of course).
Once it's done, I pour it back into bottle and keep for the next time.
The PCB is splashed with the watter which was in the bucket.
Over time I got so comfortable with it so I don't use glowes or anything.
Just the process described above and I usually do it in the bath tub
just in case I spill one drop so I can wash it right away.
No glowes, masks, open air, wearing gogles and old clothes and
using lots of newspaper. I admit that once I've ruined my jeans with it
but those days are over. Also the etching used to take only couple of
minutes and it takes almost an hour now...
Oh well, I guess it might be time to replace it in a year or so for a
fresh bottle. If one of the friends buys it in powder, maybe I can
borrow one teaspoon of it to enrich my old little bottle...

8)
 

Chilli

New Member
Try it guys!
Admit we don't have a PCB manufacturing house here within a radius of 11 000 km!
This etching solution is actually a lot less dangerous than FeCl!

It's like they say: once you've tasted chocolate you'll never try vanilla again! :D

Regards,
Chilli
 

panic mode

Well-Known Member
Hi Chilli,

I am somewhat interested because on occasion I would like
to develop board quickly but I still have some doubts:
If it's a lot less dangerous then why do you need all this gear

USE WITH GREAT CARE!!!!!!
Use eye protection!!
Do not store in air tight containers. Use it at own Risk!!

If it's not in air tight container, what happens if someone accidentally
spils the components? What happens if any of the components or
etching sollution gets in contact with skin? Does any of this creates
hazardous vapours? (Can I keep it in the kitchen or washroom
and still have no breathing problems after couple of years?
I like to keep my ferric chloride closed tightly in a plastic bottle so it
doesn't break or spill if tipped over...)

The ferric chloride is an ugly thing no doubt. It leaves stains and it
can burn fabrics commonly used in clothing. But even if I dip my
whole hand in it for 5min, all I will get is yellow/brown coloring
on my hand which will be darn hard to remove for a week but
it will not create skin burns or rush or harm me in any other way.
Believe me, it was tested on humans (at first by accident...).
The stain was similar to what you get if handling green wallnuts
(the soft outer shell has juice which leaves dark stains).

And I would have comment on the etching speed. Fresh ferric chloride
should last at least couple of months to half a year with very good results
(ca 10min or faster etching). Maybe you got bad one, or I got lucky
with mine, can't tell for sure. I just think that in process of getting
project complete, time amounts to couple of hours to couple of days.
10 minutes is not going to win the race with more powerfull solutions
but it's so simple to handle (for example, there is no need to mix
acid and watter to get the solution every time you want to make board,
there is very little danger of overexposure etc.).
I used to do 2-3 boards a day at one time. Now I'm so bussy that
I don't have time to do one decent size board more than twice a
month unless is copy of someone else's design.
 

Chilli

New Member
Don't Panic 8)


It is much more enviromentaly(geeee.... what a difficult word) friendly than ferric chloride. once used it will neutralise itself because of the copper.
What I meant with "do not store in air tight container" is that if you would want to use it again, then do not store the leftover in it. I never keep my solution 'cause it takes me only a couple of secs to make fresh solution.

Stating that you should wear eye protection and simmilar stuff is just for the record to keep my side clean. Who knows what hooligan might use it?


Oh and by the way..... if you spill it.........at least your floor will be clean!! :D

Give it a try and let me know

Rgds,
Chilli
 

Philipc

New Member
Chili
How hard is it to find the Hydrogenperoxide(H2O2 30%)? Over here the stuff we buy at the local stores only have a 3% solution.
Philip
 

Chilli

New Member
The 3% solution will not help you.
Go to your local chemist and get some there.
Or any company that sell chemicals.

It shouldn't be to hard to find

Rgds,
Chilli
 

Dean Huster

Well-Known Member
Chemistry 101

"Chemist" in the U.K. I believe is "pharmacist" in the U.S.

The eye protection is for the idiot who dilutes his acid by pouring water into it. Never pour water into acid .... always pour acid into water. Anytime you're working with chemicals that could possibly erupt in some way or splash, you need gloves and eye protection. Not a good time to emulate Tim (The Toolman) Taylor here.

HCl is available in the pool chemical aisle at Wal-Mart as muratic acid. Haven't checked the strength of it, though.

Dean
 

Philipc

New Member
This is only a thought, but could you use the muratic acid without the Hydrogenperoxide? I know the muratic acid for pools is fairly strong stuf, but not sure what the Hydrogenperoxide does in the formula?
Philip
 

Chilli

New Member
It's the strange world of chemistry.

Hydrochloric acid on it's own does nothing to copper. It's the combination of Hydrogenperoxide with Hydrochloric acid that does the trick.

Like table salt is made up of the two most dangerous chemicals. Sodium & Chloride.

Rgds,
Chilli
 

Dean Huster

Well-Known Member
A site for the "formula"

Harry Lythall's site has detailed PCB etching information using the HCl/H2O2 combination. Click on "Reference" and the top of the page and then on PCB on the following page and you'll see stuff at https://w1.859.telia.com/~u85920178/

Dean
 

spuffock

Member
As far as the chemistry goes, you will need an oxidising agent and an acid to etch copper. Some mixtures are outright really nasty, for example, chlorate weedkiller and battery acid will give fumes that explode on their own, to say nothing of the damage to your lungs if you get to breathe any. You should see the rate it eats copper, though!
The combinations are endless, all you need is a long handled grabber to mix things from a good distance!
Kettle descalers are probably useful as acids. bleaches are usually oxidisers, but the fumes are often nasty. Nitrate fertilizers are good oxidisers, but watch out for fumes.
Try anything, but use very small amounts, keep the first tests dilute, use a long handled thingy to keep yourself out of the way, and watch out for nasty fumes.
 
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