Picture of The Saltwater etch process
This is a one-off process to produce one printed circuit board by removing unwanted copper by electrolysis in a saltwater solution.

I shall illustrate the process by etching and building a board for 18-pin PIC (for the PC16F54, but any 18 pin PIC will fit in it) in the figure. It has to plug into my breadboard and accept the programming signals from my PIC programmer (just go to http://geocities.com/it2n/circuits.html and look at it).

To avoid battling with signal conflicts, the two programming pins shall not be brought to the breadboard. To play around with the clock frequency, the crystal shall be made pluggable. The Master clear signal will not be brought out.

These decisions mean a board with two .1" pitch connectors, one with 13 connections and the other with five connections, one pin spaced apart from the rest.

This is a tutorial intended for the absolute beginner, and almost every step shall be illustrated. I've even included a video of the etching process.

Step 1: Decide how large the board has to be

Picture of Decide how large the board has to be
From the diagram, the side that plugs into the breadboard has 13 connections, and the holes in the bb are spaced 0.1 inch apart. So we need at least 1.3 inches to accommodate 13 pins.

Say one and a half inches, a nice figure. Take a piece of copper clad board larger than 1.5 inches a side. Draw a line at one and a half inches.
rotor8 years ago
Thanks very much for getting around to doing this.

Btw, this is my favorite part:

Or the way I do it - use a 12V, 15A supply together with a car headlamp for indication. Small shorts that used to be there get vapourised, and if that lamp lights up, boy, that really IS a short circuit.

I actually loled.
Just a question... wouldn't it be easier to just print a design and iron it on instead of hand drawing?
Sure. But what if you don't have a printer? Or a plastic sheet that you can use to do the transfer? Doing it with a marker uses a tool that everyone is sure to have, and it gives people learning about this for the first time a better feeling for what they're doing. For the author: I like your "lotto-card" procedure. It feels like it'll produce much better results than trying to draw the traces with the marker directly.

You could of course draw the resist on in the pattern of the circuit, and touch up around fine connections (such as the IC pins) by scraping away excess mask with a pin tip (or the awl tool commonly part of soldering tool sets).

I'm all for doing things on the cheap (I etch my own PCBs because I don't want to wait for a service to do it, and don't want to pay for fast shipping), but at the point you're doing circuit design work and have ICs and components to solder, surely a secondhand laser printer isn't a big outlay. The saved time alone, not to mention savings in material use (copper PCB material for instance) will make it a quick payoff.

splud1 year ago

I have a wife, but I don't use her nail polish - I have several bottles of clear acrylic for coating windings, and a few older bottles of garish nail polishes I picked up for tamper seals and makeshift threadlock.

mbainrot3 years ago
I am attempting this now.

It should be noted that you need a substantial load when using an switch mode power supply otherwise it may not switch on
mbluett8 years ago
"One final necessary step is to paint over a line connecting all pads" What line is being painted over? This is not clear. An arrow pointing to the line in the picture would help. "In my board, the pads are all connected along the left and bottom edges." I cannot discern anything connecting the pads along the left and bottom edges. Again arrows pointing this out would help.
neelandan (author)  mbluett8 years ago
You will note (if you look carefully) that the lines scratched on the paint do not reach the edge, but stop rather short. Wherever the line is drawn, the copper gets etched away. Thus the pads remain connected along the bottom and left hand edges in this layout.
why is this necessary that they be connected on the edges, what is you have isolated connection, will it still work?
if any of the pads aren't connected, they won't have electricity running to them, thus they won't necessarily etch all the lines you need to etch. does that answer your question?
neelandan (author)  mbluett8 years ago
The offending text has been re-worded.
macumbista6 years ago
OK, so the "Sodium chloride in Dihydrogen Monoxide" solution is harmless. What about the copper that gets absorbed into it? Is the waste product of this process chemically inert (i.e. salt, water and copper sludge)? If it is, I'd be very happy to use this over Ferric Chloride and other actually nasty stuff. If not, how to make the copper inert in the solution so I can flush it down the sink without poisoning the environment?
The Electrolysis process is chemically simple. NaCl (salt) is a strong electrolyte and therefore "transfers charge".
This is really just a "redox" (oxidation/reduction) reaction.
What happends is, The Chlorine ions (Cl-) migrate to the cathode where they loose electrons and bind to make Cl2(g). This gas is toxic even in small amounts, you should read MSDS for Cl2(g). (Just type Cg2(g) into google). You should therefore perform this in a well ventilated area (or not at all).
The Copper at the cathode (the cathode is the PCB board) looses electrons and dissolves in the solution. If there is excess water a complex-ion will form Cu[(H2O)6]2+ (Octahedral aqueous copper complex with a charge of +2), but this complex will be in some equilibria with the Cl- ions. If The Cl- ions are in excess (which would probably not happen in a aqueous solution) a yellow complex Cu(Cl4)2- would form (in equilibrium with CuCl2 which is quite soluble in water).
Some Hydrogen gas could form at the anode due to the self-ionization of water H20 <---> H+ + OH- (this equilibrium lies far to the left). H+ ions would migrate to the anode, pick up electrons and leave the solution as H2(g).
When two H+ ions leave the solution as H2(g) after reduction, two water molecules will dissociate to form 2H+ + 2OH-. The OH- ions combine with Cu2+ ions to form Cu(OH)2(s) which is insoluble so it will precipitate as a green-looking solid.
So, What you have in your solution is
a) Cu(OH)2 (s) (amount is proportional to the amount of hydrogen displaced, which is proportional to the amount of Cu(s) etched away).
b) Cu[(H2O)6]2+ (amount depending on the amount of Cl- to cause...)
c) CuCl2 +2Cl- <--> CuCl3(-) <--> CuCl4(2-)
d) Some Na+ ions and water
What will leave the solution?
H2(g) and Cl2(g)

So, now you know. And what you should do if you want to know if you can flush the solution down the drain is read the MSDS for Cu(OH)2, and Copper-solutions. Although I can tell you, we don't like solutions of heavy-metals flushed down the drain. You should dispose of this properly.

I suggest you find another electrolyte to avoid the Cl2(g). I don't have many ideas tough since my access to acids and metal-nitrates and such is not limited :-).

Hope this helps
Greetings from Iceland.
Benedikt Ómarsson, B.Sc

If I'm reading that right that suggests that this produces chlorine gas, which I was told was fairly deadly in small amounts.
but there is so little gas produced you may not even get one bubble of chlorine gas and if you do it will diffuse in the air.
What about using a baking soda (sodium bicarbonate, NaHCO3) solution as an electrolyte, Mr. Science Man? ;)

To the author: I have long considered using both this etch resist application process and reverse electroplating for PCB fabrication, but you actually did them... at the same time... and you wrote instructions for us! Good show!

I plan to adapt this process to the use of my CNC router with some kind of spring-loaded scratching implement and of Peroxide+Muriatic Acid as the etchant (assuming I can find an etch resist that is safe from its ravages... I'm thinking wax).
I did a quick search.. Cl2 and H2 tend to explode when combined o_o
No biggie if you do this out in the open but if you put a lid on it to erm fend of the fumes or something you might be actually doing more bad than good.

Can't see any problems however if you just do this outside =)
chaydgb5 years ago
Superb! A refreshing change from the usual "You will require: An industrial laser cutter, an enormous budget, twenty arduino boards". Personally I photoetch my boards, but should I ever find myself in a situation where I'd not have access to my kit, I'll remember this 'ible! Thanks.
soapmaker725 years ago
Firstly, A primer on NaCl (applies to all alkali metal halides) free chlorine gas can only be evolved in quantity given three conditions are met.

1. High salt concentration in solution
2.  A pH of 7 or lower( acidity promotes this)
3. An anode(+) that is CHEMICALLY INERT to chloride or chlorine

Notice that NONE of these conditions are met in this case.  The salt is in lower concentration.  The pH will probably increase if anything(go more alkaline).  And last but not least the copper is not inert and hence it is etched. 

Secondly,  Disposal of copper waste is not an issue.  The oxides/hydroxides can be dissolved in diluted muriatic acid, vinegar, or battery acid and an aluminum wire is added until a clear solution is obtained.  This can be decanted down the drain as it simular to deodorant (aluminum chloride) or baking alum(aluminum sulfate).  The pinkish copper grains can be mixed with saw dust, oats, flour or any organic that chars black and borax and melted with a propane flame to get copper metal for later use.
rotf1015 years ago
 Thanks so much for the instructable! I used the same saltwater etching process to etch a nameplate in aluminum. It turned out great!
eclarep5 years ago
 Hey, girls make circuit boards too!
Many thanks for all this.  You have got me really motivated and I will be having a go asap.  Great stuff.
adnimo5 years ago
Dude... that's the worst soldering I've seen in a long while, even worse than my very first soldered joint... and it was a cold one, damn! you need a) better tip b) more power c) practice the tin feeding and timing, you're not doing it properly. always lift on the same direction and feed enough to solder A and B, if not you have the potential of soldering X as well and with your thin traces that's very possible.
mbluett8 years ago
For the chemically illiterate your mention of DHMO being hazardous is inappropriate. It's not even funny!

DHMO = H20 = water
Wyle_E mbluett6 years ago
*Anything* is deadly under the right conditions. Helium has no toxicity at all, but if you breathe pure helium you won't last long. The DHMO joke is very old, but there are some seriously toxic compounds that your body requires or produces. One of these days, I'm going to write an essay called "The Poisons You Can't Live Without." Start with the hydrochloric acid in your stomach,
Some of the most toxic elements (Chromium, for one) are deadly in even small doses but essential in tiny, tiny doses. This is true for hundreds of other compounds, elements, substances, etc. What I want to know is who figured out that sucking on dynamite is good for you! (GTN (glycerol trinitrate) aka nitroglycerine is found in explosives, however is used in hundreds of medications to reduce blood pressure, and used as a reliever for angina sufferers.) Helium can also be very useful - BOC produce a gas known as HeliOx (He & O2 in a 8:2 ratio) used in hospitals (mainly intensive care) for asthma sufferers, as the 80% helium content makes the gas a lot more 'slippery' than air. This results in it being much more breathable; easier to get the oxygen in, and since it still has a 20% oxygen content no ill effects are had. Apart from sounding like a castrated mouse due to the higher resonance caused by inhaling helium.
Actually it's very funny. The page is a satire of irrational environmentalism and of people who are afraid of all "chemicals." I like the statement that "DHMO has been found in high levels in many lakes and streams in the US."
neelandan (author)  mbluett8 years ago
... and I might humbly add that that website is really preposterous! ( http://dhmo.org )
berin8 years ago
Time to educate you moron's on this, this is not some great easy quick method for producing a PCB board. This produced chlorine as a bi product, 5min of run time can produce a deadly lethal amount amount of Cl or also known as Chlorine. What you produce in a small VAT in this example is almost 2x what your YMCA uses to keep there entire POOL clean. AGAIN THIS IS A DANGERUS AND DEADLY EXPERIMENT. DO NOT TRY IT!!! besides putting this down the drain will kill a septic system AND will really really piss off your local wast water treatment plant to the point that they WILL investigate were the source of Chlorine is coming from. DANGER!!!!!
Er, isn't it going to produce copper chloride if you're dissolving copper in salt water?
Yes, at a high enough amperage this process will produce Cupric Chloride. Not the nicest of chemicals, but as long as you're not etching a full-size motherboard you should be fine. -recon506
i have just noticed something... doesnt cupric chloride etch pcbs??? if so, you could get a blank board and make some cool cupric chloride to etch your boards couldnt you? any suggestions please.. :) James
Wesley666 berin6 years ago
What if I do this outside, and dilute it before it goes down the drain? As well my water is almost completely distilled with just a bit of sodium because it comes from an underground source below my farm. Besides you can always use something other than salt, that will do the same job just as well.
... Any Cl gas that evolves, easily dissolves into solution (as gas). Cl gas and H2 gas that does escape are not deadly in such tiny concentrations. At most the Cl would be an irritant in an 3 x 3 meter room. It is all about the concentration. The waste water will never even know about the chlorine content... Any Cl gas would probably react with something and the Cl ions are so common in water (you get the same Cl ions from road salt). However, The EPA and your local DNR both care about copper ions being released into the ground water supply.
Could you give more info/ sources please? I'm not saying you're wrong, but if it's true it's something I'd like to know more about. In what way does it harm a septic system? I've worked on them and installed several, and except for something harming the pump with prolonged exposure (similar to using lye cleaners very often) I can't see how the chlorine would hurt a drain system. How does the concentration of chlorine in this solution compare to that of common bleach?
steven07 berin8 years ago
At first glance i see no Cl being produced Cl is normally only produced by electrolysis in normal saltwater when you have more than a Concentration 4M. otherwise gas is 1/3's O2 and 2/3's H do you have the reaction to help explain to me how Cl is produced ( perhaps when you do electrolysis you us too much salt)
oh had a look over people doing electrolysis Don't make a saturated salt solution and you should do fine, So a Maximum of 100g per L should be fine for no cl being produced
had a look at some electrolysis information and i believe: The Cu anode produces Cu 2+ ions which would like to bond with Cl- anyway (the fore no free cl gas is made) however its probably likely that the NaCl will only act as an electrolyte and CuO will be the only by product. Any gas produced if the Solution is under 4 mol will be the reduction of air. ( gas will be produced at both electrodes if you use more volts than you need even if the anode is inert, the gas produced will depend on the concentration as stated above) All reactions pretty much stop when electrolysis stops, You should to even be able to ingest some of this mixture and come out alright. Heres some more info.
I'm not a chemist, but it seems to me that the chlorine is instantly combining with the copper, forming copper chloride, which is the yellow stuff you see in the solution. So my guess is that it's probably not producing very much chlorine in the end. Like I said though, I'm not a chemist. Great instructable by the way; I think I'll try it the next time I use a SMT chip.
What about using sodium carbonate? I don't know if the salt here really does anything but increase conductivity...
Yep Sodium carbonate should work . if you want to see for yourself the likely products of any salt when electrolyzed. look at the flow chart i posted below yep pretty much the salt here is just increasing the waters conductivity
neelandan (author)  zachninme8 years ago
Why not try it, then write and tell us?
0x0000 berin8 years ago
"time to educate you moron's on this"
think pretty highly of yourself, do you? How about instructing us on the proper capture and handling of the Cl during after the process? Some of us may have a use for such things. You come across here as just another timid ignoramus. Like, do you really think the average person needs telling that Cl is poisonous to humans? Grow up, possuer.
jtobako berin8 years ago
Since when is a septic system attached to a waste water treatment plant? A septic system IS a personal waste treatment plant! If the chlorine is released as a gas, how is the treatment plant going to ever see it? Now, if you were going to talk about copper contamination, you might be able to make a point-until you look in your pocket at the change there or the pipes bringing water into your home. Let's talk about volume. A swimming pool uses up to 6 cups of chlorine additive per week, assuming that salt has as much chlorine do you really think that he got 2 cups of salt to dissolve in that tiny tank? And it's all coming out in 5 minutes? I think the MORON is in the MIRROR.
neelandan (author)  berin8 years ago
The above warnings apply to the intelligent humans reading this as well.
ledgar117 years ago
0hi im new to the pcb deal and i had a question if the whole board is made out of copper doesnt the circuit cross with the electric current
He made his circuit the OPPOSITE way that you'll normally see. Normally there are small lines of copper. What the author did was make a large section of copper & seperate the sections by making a line that's non-conducting. You could just as easily do the reverse process and use the marker to create a trace (as is more normal looking), but you might need to etch multiple times as the solution may not continue etching properly or at the very least for a longer period of time.
Samodelkin7 years ago
To me, this seems like the perfect solution to two problems: etching single-side PCBs and getting started with SMT. The biggest selling point to me is the lack of dangerous acids; however, I am a bit apprehensive about the residue in the water after the process. What exactly is it? Is it safe to dispose of down the drain? Could someone find some chemical equations for this process? (I know little about chemistry, so when it comes to chemical safety, paranoia is the best replacement for knowledge that I have.) Seeing that this instructable is over a year old, I am led to assume that people are using this technique with no incident. However, it's not like someone would post here immediately after they die from it. (I'm sure this is an exaggeration though. I hope.)

After a bit of internet research, I concluded that the precipitant residue after the process is probably Copper (II) Hydroxide. Note the synthesis process: copper anode (the board) in electrolysis of water with some electrolyte in it, salt in this case. However, that still doesn't answer my questions about proper disposal procedures.

So far, I predict the reaction equation looks somewhat like this:
2 H2O (l) + Cu (s) >> H2 (g) + Cu(OH)2 (aq)
Could someone who knows chemistry please confirm or deny any of this?


By now I'm rather certain that you can't just pour Copper Hydroxide down the drain. Because it's insoluble, however, it should sink to the bottom, allowing the liquid to be poured off and decreasing the amount of waste that requires "proper" disposal. Other potential byproducts are Copper(I) chloride and Copper(II) chloride, assuming table salt is used for electrolyte. This is because the negative Chlorine ions would bind to the positively-charged copper plate. Alternatively, if baking soda (Sodium Bicarbonate, NaHCO3) is used, the most likely thing to accumulate on the PCB is Copper(II) carbonate, because carbonate would be the negative ion.

The disadvantage with this method is the constant output of potentially-hazardous waste that requires proper disposal. According to this site, however, Copper(II) sulfate can be used as an electrolyte, with the advantage of not undergoing chemical change; that means the electrolyte can be re-used indefinitely. It should be commercially available as herbicide/fungicide for gardening purposes. (see Root Killer)

Again, I know little about chemistry and this is just a guess, so I would like to know if anyone can confirm/deny this.
hosam_eldin7 years ago
Thanks for the great idea but i think it can't be used with the toner transfer PCB i have tried it , the problem is : when you try to etch a large area, some copper is etched and disconnects the current and the process may stop leaving many copper spots on the board. here is an image when i tried to etch my name. you can see the bad result
maybe you did not clean your clad enough, it looks dirty and a bit smudgy. check this site out, it's in much details:
i would try etching a few centimeters (or millimeters) at a time. start etching with the electrolyte level low, then gradually fill the container until the board is complete. (though i think that may lead to uneven etching.)
step 15 does say that all areas must be connected. You would be better off with the negative of the shown piece. The other problem is that it works better with thin lines being removed so that there isn't much of a chance that islands would form (step 21, Testing the board for short circuits), but it happens anyway.
Bobv7 years ago
Does anyone know how well this works with toner transfer method as opposed to scratching the board? Also is the remaining water safe to just dump down the drain (as opposed to chemicals used to etch boards which can dissolve your piping or whatever)
neelandan (author)  Bobv7 years ago
With toner transfer you will need to etch for a longer time. This is because of the larger amount of copper which needs to be removed. The resulting solution of copper chloride mixed with salt should be safe to flush down the drain. It is not acidic or alkaline, as the etching agent is the action of the current.
LOL, your using electrolysis to etch the board!!! I never throught of doing that to corrode that anode side and have the printed board remain. This technique is awsome!!!
nah, hes just pointing out that your oblivious family members could possibly, inadvertantly poison themselves and that chance should not be taken...
Thermionic8 years ago
I used a storm trooper, and this worked fine. I couldn't find a suitable tweetie. Great instructable!
cj9train8 years ago
perhaps you can use powdered detergent/epson, and thus eliminate the chlorine gas.
Macka8 years ago
I suggest you use a single-cut file (has "teeth" in one direction only) for cleaning up the edges of the board, and using steel wool for cleaning up the surface of the board, this goes for removing the etch resist after etching. also, if you drill your holes before removing the etch resist (with the steel wool) you will find that the "barbs" around the drilled holes will be significantly cleaned up.
robotechuk8 years ago
Good instuctable, definately something to be carefull with. Although, its not like conventional etching isn't without its hazards. If the board is small enough, you could just remove this small ammount of copper with a Dremel. Thus removing the death from chemicals or local authorities threat, and you could do it indoors:)
OverUnity8 years ago
Thanks so much. Finnally an etching process I can afford!
binnie8 years ago
binnie8 years ago
with the electrolosis thingy! * ive done electrolisis in scinence haha we blew up test tubes lol ive made an electrolosis enging for my lawn mower from scratch too !!!!) doesnt the whole board have to be in electical conatact with teh positive or will it etch towards the postive clips or whatever??????

If you etch off the power supply it wont work?? and is the salt mix do the corosive bit or will just plain water do ( NO my past experinces say it wouldnt )
binnie binnie8 years ago
mrmeval8 years ago
I don't know if it would effect the solution but most salt has iodine in it. You might try iodine free salt at some point just to see.
rich2003138 years ago
Theres gotta be some thing wrong when my solution starts to turn yellow with a black fog/mist/cloud/thing. Is this normal or should i probably evacuate my street?
neelandan (author)  rich2003138 years ago
It is normal for the solution to turn almost all the colours of the rainbow. Just make sure that the material to be etched (PCB) is connected to the POSITIVE of the power supply. That mist probably contains chlorine and copper, both poisonous, so this should be done somewhere with good ventilation.
LOL. OK then, thanks for the quick response. (IM NOT GONNA BLOW UP!!! WOOOOOOOOOOOOOOOOOOOO!!!!!!!) Thats not right. Looking at the times you answered beforw i even asked the question!!! Youve gotta love time zones, they really mess everything up. Oh yeah and its not right that i wont be blowing up while messing with electricity (HAS THE WORLD TURNED UPSIDE-DOWN!!!!!)
mtxe rich2003138 years ago
no it 's 12am1am 2am... ...10am 11am 12pm so its not the time zone
shadowman28 years ago
Wow!! That's a lot easier than the other methods !! Thanks for this great instructable! It's my favorite.
rachel8 years ago
Just want to point out your (presumably inadvertent) assumption here about your reader, that a) he is male, and b) he has a woman to keep house for him. I am female and keep my own house, but I will definitely be trying this process for my next one-off board project, as it looks relatively simple and quick and is truly excellently documented.
neelandan (author)  rachel8 years ago
It reflects my case - I am male, and my wife (and daughters) keep house.
Yes, obviously! Nevertheless, not all your readers are just like you.
Roflolommo8 years ago
hey you coulda come up with a new sport in the process too extreme etching drop a car battery into the solution and try and get your board out.
nickjohnson8 years ago
I tried this last night, and it works great. Thanks!
TecDroiD8 years ago
what about using this technique together with the laser printer on foto paper?
EuroBoy8 years ago
I use similar approach for making PCB. A bigger iron nail is wrapped at one end with cotton, soaked with salt solution. The nail is connected to the negative plug of 12 V / 1A transformer. You wipe away the copper from the board with the cotton, which turns green after certain period - then you replace it with new one. This method is quick and effective.
This is very clever!
nickjohnson8 years ago
the dhmo link tricked me for a second. lol
neelandan (author) 8 years ago
Thanks for the positive comments. I have not tried this with the regular type of patterns that pcb drafting programs put out, but I suspect that the etch resist will have to be of higher quality to withstand immersion for the longer time that will be needed. Perhaps one of you will try it and let us all know?
westfw8 years ago
The problem with this method is that step where you have to cut the traces apart. Since you need electrical connectivity to the portions of copper that need to be removed, you MUST have extra copper when you're done, thaat you'll have to cut away (sort of simiarl to the sprues of plastics molding, in reverse) With a generic PCB design, you're going to have places that are particularly annoying to cut. It might be possible to design a PCB to minimize this problem, but the idea makes my brain hurt just thinking about it; it's bad enough just trying to make single sided designs...
hanelyp westfw8 years ago
Should help to immerse the board very slowly into to etching solution so that the unetched portion in the solution is always connected to the unetched portion not yet immersed. Think etched divisions between traces growing from one edge towards the other. A trace isn't disconnected from the bulk until all sides of it are etched.
This is awesome where did you get this idea? you say "My approach helps to keep the maximum amount of copper on board, and minimises the amount of material to be removed. This is important, otherwise the etching process will be too slow." Can this etching process be used with the type of board eagle puts out? I realize this would take longer to etch but would it work? also "One final necessary step is to paint over a line connecting all pads - this is necessary for electrolysis." this is just so all the traces get current right; you cut them apart later?
xsmurf8 years ago
Very nice instructables! A+++ We've all been waiting on this one! I'll have to try it out soon. So far the only thing that has stopped me from making my own PCBs are drilling the holes as I don't have a drill press and drilling sometimes hundreds of holes seems quiet tenacious... I guess SMD solves this problem, but it scares me a little. Thanks again for the post!
You really can SM almost any normal item, as long as you don't mind it looking ugly. You just melt a blob of solder onto the "joints" solder on one side, then the other (pushing it in somehow without burning yourself...). To trim, take a flathead screwdriver and push on the extruding leads. they are cut in half :-)
AlfonsVH8 years ago
Very nice indeed! I like it very much and I may test it soon.
leevonk8 years ago
cool process. Seems like if you're only removing that much copper though, you could just use a dremel with a sharp sander tip to make those same traces. A flexi-shaft would probably help (so you don't have to hold the whole dremel)
HamO8 years ago
Great instructable, can't wait to try it. Exceptional photos, well done!
ian8 years ago
Wow! Thats really cool. Can I use the salt/electrolysis technique on my photo-resist boards? It seems like it would save me a ton of money on XXX-Persulfate. I can't see myself hand-carving traces for a QFN, but I would love a cheap new etching solution. Great instructable!