> chemistry > divers-inorganiques > copper-chemistry-around-echants > make-ferric-chloride-for-etching-printed-circuit-boards-nurdrage

Make Ferric Chloride (for etching printed circuit boards)

NurdRage - 2012-11-15

We make ferric chloride, a well-known etchant for printed circuit boards.

Get 20g of iron. This can be in the form of nails or steel wool. It's best to use iron that's rusting, that indicates it doesn't have other metals like zinc or chromium that's normally used to prevent rust. To the iron add 100mL of water and 100mL of 12M hydrochloric acid. The iron will start reacting with the acid to produce hydrogen gas and ferrous chloride. If the reaction is proceeding too slowly for your liking you can heat up the mixture. A flask of cold water on top is useful to reduce evaporative losses.

Once the ferrous chloride solution is made it needs to be oxidized to ferric chloride. The fast way of doing this is to add 200mL of 3% hydrogen peroxide. Do this slowly with lots of stirring as the solution will heat up a lot. If it gets too hot to hold (about 60 celsius) stop and let it cool before adding the rest of the peroxide. If you don't want to use peroxide the slow and cheap way of oxidizing it is to bubble in air using an aquarium pump. It can take several days but it has the added advantage of keeping the solution concentrated.

After oxidation you'll have a solution of ferric chloride ready for use.

Triune Blades - 2018-01-16

Ferric chloride is awesome for etching knife blades! Thanks for this video!

Redda - 2012-11-15

Love your videos, they help time to time in my chemistry exams ^^

rubblebuzz - 2012-11-16

I love this guy. He gets me interested in science and chemisty...my true loves of life :)

supremeruler1968 - 2012-11-16

Love your videos - Thanks for your good work - I enjoy it very much Any chance you could show us how to make H2O2 ?

Terry Flamingo - 2012-11-24

Could you go through the Fenton Reaction you used during the last oxidation step? It is a fascinating piece of chemistry that tends to go under appreciated, and I was quite surprised when you used it.

Angel Gonzalez - 2016-07-09

its amazing how simply this can be made with storebought concentrations of these chemicals and end up being far cheaper than buying pre-made ferric chloride.

MSteamCSM - 2012-11-15

Thank you so much! Also, woud be great if you show how to recover the solution after it has been used a lot, and not working anymore.

Daryl Warner - 2014-03-24

Thanks for the tutorial. We use ferric chloride in ceramic to make great colors on rakued art. Can buy small bottle for $9, now we can have lots for little cost. Thanks NurdRage

WeaselWJ - 2012-11-16

You should do some tellurium chemistry! :D

Tricknologyinc - 2014-03-12

Is this good for through etching aluminum, and what is the safe way to dispose of it when you are done? Also, why not etch with the HCL?
Also, when you heated the solution, did the acid evaporate or just the H2O?

Griffin Kowash - 2014-04-05

@Tricknologyinc I'm not a welder, and I don't have experience in commercial production, so take everything I say with a grain of salt.  What works for me may not be best for you.  Etching with the copper chloride will only work for copper, and on a large scale like you're talking about, the amount of etchant that's produced with each run could certainly be problematic.  As for spills, copper chloride is toxic, so it could certainly pose a hazard in the case of an accident.  It may erode bare concrete, so you would want to have all of your acid in a space with chemical resistant floors (such as sealed concrete.)

In the case of a contained spill, you can neutralize it with either dry or aqueous baking soda.  This will form a solid precipitate of copper carbonate.  The copper carbonate is far less toxic and can be very easily collected for disposal.  The remaining solution can be safely washed away, because it is now just sodium chloride.  If your solution is acidic, carbon dioxide will be evolved in the neutralization, which could possibly cause problems if you're in a small, unventilated room with a lot of acid to neutralize.  Basic chemical safety procedures apply for individuals working with chemicals--gloves, goggles, chemical-resistant clothing, a close source of running water (ideally a chemical shower, otherwise a sink), and an eyewash station.  If chemically etching aluminum, you would probably have to use hydrochloric acid or sodium hydroxide instead, since aluminum doesn't have two convenient oxidation states like copper.

Electrolytic etching is another alternative, and it sounds like something you're more familiar with.  If you're planning to do both etching and plating, you could experiment with doing both at once.  Attach the piece to be etched at the anode, the piece to be plated at the cathode, and electrolyze in a copper sulfate solution.  The reaction will dissolve copper from one end and deposit it on the other.  One nice part is that there is no net change in the electrolyte composition, because Cu2+ ions are already present, and the oxidation of SO4 2- will end up producing CuSO4 again.  Copper sulfate is also slightly toxic, but can be disposed of similarly to copper chloride.  Aluminum electroplating is not especially practical, but you can read through this patent if you want: http://www.google.com/patents/US3236751

All of these methods require a lot of more precise planning; namely, preparing the pieces and treating them to ensure an even etch/plate.  Organic compounds and oxide layers are an issue.  Pieces must be washed in acetone and sanded very well to remove these.  Skin contact, environmental factors, and long exposure to air can reintroduce oxide layers and oils, so you'd have to keep it very clean.  Also, during processing, pieces tend to collect bubbles that inhibit the reaction and result in uneven blotches.  A couple of ideas would be using constant stirring to keep it agitated, or bubbling air underneath each plate to collect the attached bubbles.

In short, it can be safe with careful planning and proper safety precautions.  Each method has pros and cons that change depending on your material and desired product.  If you plan to go commercial with this, I would recommend consulting someone who specializes in these things or a licensed chemist.  Sorry, I've probably rambling on for way too long.  But I hope this helps.

Griffin Kowash - 2014-04-05

@Tricknologyinc Ha, good point!  Yeah, maybe that wouldn't be so great for circuit boards or other insulator-backed metal.  Solid blocks of metal should still work though.

Tricknologyinc - 2014-04-12

@Griffin Kowash
 I really appreciate your input. I know how hard it is to stop. There's always something life and death that was left out... This will be a nice primer and study guide for further research before talking to a chemist. Thanks much.

deltaxcd - 2014-06-30

@Griffin Kowash
You are wrong:
HCL mixed with H2O2 will etch anything I guess even gold.
I used that solution to recover silver from brass/silver mixture.

also Iron chloride is equally reusable as copper chloride because you can regenerate in same way.

user21XXL - 2014-07-28

@Griffin Kowash Fe(III) based etchants also can be recycled.
Atmosferic oxygen will oxidize Fe(II) back to Fe(III) but H202 is faster 

Coppertools - 2016-03-26

Very informative video. Which Baumé will be the final produced FeCl3 with this method? Are there any calculations to perform differents Baumé of this procedure?

NurdRage - 2012-11-15

A large fraction of my viewers are DIY hackers, makers, amateurs and electrical engineers. This video is for all of you.

Mustafa Abbas - 2013-10-06

Thank you very very much for this great video. But a question please " Could i use a H2O2 of 25% instead of 3% " i'm waiting for your answer ...

Denton - 2012-11-15

Thank you so much!!! I needed this to etch my Damascus steel!

Swaminarayan Joshi - 2020-07-28

Did you get desirable results ?

Yellow Chemist - 2021-02-22

@Swaminarayan Joshi well, that was 8 years ago

Mooncabbage - 2012-11-15

This video was awesome. It seems like something I could do (carefully) at home. Not really sure where I'd source the acid and the peroxide, let alone at the right concentration, but if I wanted to I could work it out. So yeah, more home chemistry plz.

NurdRage - 2012-11-16

Its weird that no one ever requested hcl/peroxide but lots of people requested ferric chloride. Then when i show ferric chloride i get a large number of people requesting HCl/peroxide. ah well ;)

Joseph Massimino - 2018-11-09

You can't please everybody. Thanks for all the education you share with us.

Shawn Gilley - 2012-11-16

Thanks, use this in my shop and it is pain to locate sometimes. Easier to make and have volume. Your the best channel on here

Railgun256 - 2012-11-15

thank you! this should save me from dealing with the local radio shack

iguanian - 2012-11-25

Hello and thanks for the video! Can you tell me what the chemistry is in my result? Used electronic scrap, partially to dissolve the steel before going after the Au, Ag, etc. Solution was as you showed, but there was some additional black sediment (carbon from the steel?) and more interestingly, much of the remaining metal is now copper plated. HCL doesn't react with Cu, at least not like that, so what caused copper plating to occur? Can provide pictures if you are interested. Thanks!

Eric Williams - 2013-07-08

I was wondering if there is a good way to recycle this or at least neutralize it for disposal?

panagiotis seremetis - 2014-04-07

Thank you very much your tutorial is extra informing

Schindlabua - 2012-11-16

Whoa, the new Intro is great!

rene kenshin - 2015-09-12

So this is how it's made, cool :D

Mike Suopys - 2013-06-09

Can I also get Fe(II)Cl2 from the electrolysis of Aquarius NaCl and a positive iron electrode? I was originally trying to speed up the process of creating Iron (III) oxide by adding salt (my friend told me to do that), however I got a product that looked more like Fe(II)Cl2...Brown powder. I figured that most of the brown powder came from the iron oxidizing with the Cl- ions in solutions. I also was unsure if the Cl would turn directly into a gaseous state, so I did this outside.

Max Goodacre - 2012-11-16

Back to Basics: Can you please make a series of short videos teaching us how to make simple acids, bases, compounds needed in most general experiments?

Denamic - 2012-11-16

I knew it! Alchemy is real!

Michel PASTOR - 2012-11-15

Very good. I always wondered how to make ferric chloride as I use it to etch my PCBs.

Sheylla Tatiana Reyes Atuesta - 2016-06-09

how could determine the concentration of the solution of FeCl3?

Eli Bane - 2013-02-27

So if I let it dry into crystals, what's the best way to bring it back to liquid?

Johnpao215 - 2015-12-06

"That pathetically weak pump". :)

NurdRage - 2012-12-06

This video was made because a lot of viewers requested it. Let me know if you think i shouldn't listen to my viewers. Oh wait a minute, you're a viewer.

mgregggphone - 2012-11-15

As always, this is a really great video. Would it be possible to make a video on making potassium persulfate or sodium persulfate? Those two chemicals have been my preferred copper enchants for years now.

sabadara - 2013-02-13

How did you remove the layer of Fe(III)Cl3 on the glas?

Snorri Ö.K. - 2020-01-26

Thank you for the air pump solution. Now I don't need to buy a 10 gallon bottle of a hydrogen peroxide concentrate when I only need like a 0.1 liter or less.

عربي مغربي - 2020-06-30

Great video, i have a question, what if some Hydrochloric Acid is still present after oxydizing the ferrous chloride ? How to make sure all the HCl has gone ?

Samuel Xu - 2020-08-24

hcl evaporates very quickly, so drying it out would help. or you could just add an excess of h2o2 and wait an hour

hajikhanom - 2013-04-25

All your videos are amazing. Do you have an idea how is EDDHA produced?

Robert Sacks - 2014-12-06

thanks for de-mistifying things we use.

Komkast22 - 2012-11-24

This is one of the most interesting channels ever

Newoice - 2013-10-08

And how much is concentrated Ferric Chloride made by this process?

Linuxdirk - 2012-11-16

I watch all your videos even if I’m not actually know what you’re talking about :)

Grant Nayduk - 2012-11-15

Can you do a video to recover the Cu from the HCL?

tyler krug - 2020-04-02

I love all your videos!

Will Flock - 2016-07-21

Dammit, every time I try to boil acid it erupts! First vinegar, now this.

Moist - 2012-11-16

Can you do an episode on how cool mercury is?

Gabrulo_Knifemaking - 2017-11-03

It will work if you add the hydrogen peroxide before speeding up the dissolve of the iron?

shad0ex - 2012-11-16

What solvent do you suggets to recrystal the Ferric (III) chloride. I would love to have nice pure crystals!

totoritko - 2012-11-15

I remember this from high school - we used to keep this stuff in a Coca Cola bottle (it even has a similar dark-brownish tint) and joked that coke dissolves even the copper on our PCBs :D

science mode Laboratory - 2018-09-17

Can we make FeCl3 battery. If yes how much its voltage will be.

Mr. Probe - 2012-11-15

nice video! h2o2 + hcl also work to decompose copper

Victor Augustine - 2016-07-13

Great, and thank you VERY MUCH..!!!! I follow the procedures and made the chemical. I successfully etched beautful boards with it. It only turn green after etching few times. What to do when that happens? Add more hydrogen peroxide help? by the way I didn't have the acid you used so I used battery acid... but it is also 37%

Vladislav Damqnov - 2016-12-09

Victor Augustine umm battery acid is not hydrochloric acid, but sulfuric acid. If you have sulfuric acid you can skip the iron part, just add hydrogen peroxide and you're good to go. Alternatively you can add table salt, and turn the sulfuric acid into a crude version of hydrochloric acid.

Victor Augustine - 2016-12-10

Vladislav Damqnov thank you so much. So just to be clear I would still get Ferric Chloride just by adding hydrogen peroxide the the battery acid I have here. A question is, should I use the the same ratio described in the video? ALSO, what amount of salt I should add to the acid to get hydrochloric acid. How strong will be the resultant hydrochloric acid compared to industrial hydrocloric acid. I have recently purchased hydrocloric acid (Industrial I suppose) and I have to mix it with water in 2:1 ratio. (water:hydrochloric acid) and it etch my pcb with in 8 minutes. I do not know if I make this crude hydrochloric acid I will still have to add some water to reduce its strength. Again, thank you so much.

Vladislav Damqnov - 2016-12-10

No nurdrage described it in another video i think, you get something else

Victor Augustine - 2016-12-10

Thank you, Friend.