Make Ferric Chloride (for Etching Printed Circuit Boards)
Intro: Make Ferric Chloride (for Etching Printed Circuit Boards)
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.
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.
19 Comments
MoonDog Knives 11 months ago
Howiesf 3 years ago
sparksd 7 years ago
Hi all, I made a small batch of this and things went perfectly. Thanks NerdRage! Something to think about is that this recipe 'Makes' a dilute solution. 3% hydrogen peroxide and 50/50 water/hydrochloric acid adds a lot of water into the mix. There should be a way to make a much more concentrated solution.
Using 10% hydrogen peroxide would reduce the amount of water in the solution by about 15% or better yet, use the bubbling method described. Eliminating the 50/50 mix of hydrochloric acid/water and using straight hydrochloric acid would further reduce the dilution by another 25%.
I am no Chemist, but I feel like one after this exercise, so please don't try these suggestions without careful consideration. The reactions will be much more energetic and controls will need to be in place for safety; (Ice bath, slow additions, etc...)
Started out etching circuit boards and got sidetracked with this endeavor
Thanks NerdRage :/
nabzim 7 years ago
--scientists-- 7 years ago
SHOE0007 8 years ago
When Hydrogen peroxide is added to cobalt (II) hydroxide it forms cobalt (III) hydroxide. This is much easier than trying to create cobalt (II, III) oxide.
SHOE0007 8 years ago
Slightly off topic but I just recently bought COBALT CHLORIDE HEXAHYDRATE and I use it for all kinds of experiments. I have found that you can cobalt plate with cobalt chloride and 25% HCl.
Tip: A quick way to neutralize cobalt chloride is to add lye to it. It should turn blue dark blue. Then add hydrogen peroxide 35% a few ml at time. Do this in a WELL VENTILATED AREA due to lye fumes + cobalt being released. This forms cobalt (III) hydroxide which is insoluble even in strong acids like Nitric or hydrochloric. Very few acids can attack coblat(III) hydroxide!!
SHOE0007 8 years ago
Slightly off topic but I just recently bought COBALT CHLORIDE HEXAHYDRATE and I use it for all kinds of experiments. I have found that you can cobalt plate with cobalt chloride and 25% HCl.
Tip: A quick way to neutralize cobalt chloride is to add lye to it. It should turn blue dark blue. Then add hydrogen peroxide 35% a few ml at time. Do this in a WELL VENTILATED AREA due to lye fumes + cobalt being released. This forms cobalt (III) hydroxide which is insoluble even in strong acids like Nitric or hydrochloric. Very few acids can attack coblat(III) hydroxide!!
raypsi 8 years ago
I has an oxygen generator takes air and makes 98% pure O2, will that bubble the mix faster? gr8 job merci beaucoupe for sharing
ClownW 9 years ago
I have made a batch of Iron (III) using your protocal and it reduces to a chocolate brown and does not fall out of solution in crystal form..... I cant figure it out. I use rusty nails and the same ratio of di water to hcl... I reduce it slowly. More like evaporation. It just gets thick and then turns into a hard puck that looks like chocolate.
Any help would be great.
Awesome-aniac 11 years ago
kidNeutrino 11 years ago
I am not really sure you can call an advantage here. Stripping copper through chemical processes creates a resultant substance that you need to treat carefully, the spent copper-laden corrosive is fairly toxic and many states require you to take it to a approved haz-waste collection site. I think NR is doing the awesome thing of making everything from base materials, the holy grail of us 'structable nerds.
Back to advantages for a second though, I have read the cupric chloride etchant( I believe that is what you referencing) can be reinvigorated and thus it has a longer used life ounce for ounce. It still need to be treated with respect and caution.
stihl88 11 years ago
dimeH 10 years ago
Pour top inch of reclaim-liquid into second iron-shavings jug as top inch of reclaim is foamy and toxic-looking. Under this foamyness is emerald green,
"de-coppered" iron (two) chloride. Pour this into empty jug. Stop decanting
this fraction when it begins to appear murky-grey. This, of course, is the copper
hydroxide becoming entrained.
Add 30Vol H202 to convert emerald-green Fe(2)Cl into our desirable (brown) Fe(3)Cl.
The reclaimed Fe3Cl is less-potent-an-etchant than the original store-bought Fe3Cl and tends to spontaneously convert back emerald-green Fe2Cl (not sure why?) but addition of additional beauty-supply store 30Vol H202 "re-energizes" things.
Household ammonia, cut 50/50 with tap water, "neutralizes" any spills and may
take fresh Fe3Cl stains out of carpets and clothing.
Weigh in with your thoughts on how to increase etchant-strength and "staying power" of reclaimed Fe3Cl.
cunning_fellow 11 years ago
That is it creates sharper edges and finer details. Was not making a moral judgment on value/environmental-friendliness/street-cred. It just works better at eating metal in a controlled manner.
CuCl is close to the results of FeCl on copper. But on some other metals it does not come close.
cunning_fellow 11 years ago
oanderson 11 years ago
Orngrimm 11 years ago
It produces very unhealthy fumes if you evaporate it, right?
Is there a temperature-limit in evaporation i shouldnt cross (Decomposing stuff)?
Or is it even best to let it sit without raised temperature till it is evaporated?
Bobblehead Einstein 11 years ago
Happy to see him here :)