Instructables
For my latest electronics project I decided to make a resistor substitution box, instead of just using another perf-board I decided to make a pcb for it so I could document the process and make an instructable. I decided to do this because I have yet to see anyone do it on Instructables so I figured it would be a good thing to share. This process works well for simple circuits that do not have a lot of small parallel bus lines in them, I have done a few guitar stomp boxes this way as well.
 
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Step 1: Materials

Materials to design and Draw the board:

-Paper and Pencil
-Ruler
-Sharpee
-Tape
-Scissors
-Tiny #65 twist bit (0.035" which is good for most electronic components)
-Dremal or pin vise to drill holes, the Dremal is the obvious winner here
-Copper clad PC board

Materials to etch the board:

-Ferric Chloride(FC), which is used to etch the board
CAUTION Ferric Chloride is a very corrosive liquid the vapor well cause steel to rust, therefor one must take all precautions nessessery in order to protect yourself as it well cause nasty burns and alike. So therefore you well also need
-Rubber Gloves
-Safety Glasses
-Paper towels to clean up spillage
-A well ventalated work area as the vapor is also quite nasty and not good to breath in.
Aside from all the safety stuff you need,
-A small resealable plastic container to put the FC into for etching and storage afterwards.
-A larger plastic container that the small one well go into for water and storage of materials afterwards.
-Warm water, goes in larger container to heat the FC.

Step 2: Designing the circuit

Using paper and pencil design the layout of the circuit, it is easiest to do this as a top view of the board, it helps to also have all the different components on hand to help with spacing and placement. As a side note also make sure to design the layout so that it well fit on the board. If you already have a pre-designed layout you can skip this part.

Here is what my layout looks like for the resistor substitution box.
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Why we use Ferric Chloride? Is there any other way for Ecthing Process?

There is an Instructible for home-brew etch with an HCL (pool acid) recipe.

Ohm (author)  gauravkpatil.9735 years ago
Because I had it, simple as that, it is nasty stuff though. If you do some searching there is an instructable on making a homemade etching solution that is cheaper and I think I little safer, when my FeCl runs out I well be making some of that stuff.
Dipankar5 years ago
Check this out.
Draw your circuit directly on the copper board and drill the holes.
Paint the Circuit with NAIL POLISH.
Then start the Etching process.
The Nail polish will save your circuit from being etched.
The places not covered by the nail polish will be eached.
Job done.
hmm maybe correction fluid? the type of pen that the shop here sells to mark is a "paint" pen.

I tried white out for artistic etching once. I found it rather hard to work with for even simple lines, and it had a tendency to lift in spots. Note that I was biting deeper (2-3X ?) than a PCB.

Ohm (author)  Dipankar5 years ago
Yeah thats another way to do it, I think the Sharpee method is much easier to do and gives cleaner/finer lines.
dcutter15 years ago
Anyone ever try the type of pens that have metal in the ink and are prmanent like this one - Sanford Silver Coat and Gold Coat Markers Permanent, fadeproof, waterproof. Metallic ink works on most surfaces. Acid-free.
eruger dcutter11 month ago

I would be leery. Some of those pens have mylar, or mineral flakes/dust, of unknown chemistry. Others have various metal powders/flakes, again of unknown chemistry, and all of them are paint rather than ink, with a wide variety of binders and fillers, again of unknown chemistry. I speak only from the expert knowledge of my ignorance, mind you. I wouldn't try it without some extra precautions. Who knows what you'll get?

Ohm (author)  dcutter15 years ago
I know there is a special pen that you can buy to repair pcb traces, it might be interesting to see what kind of conductivity that the stanford inks have and again it would be only for repairs as you couldn't solder too it.
dcutter1 Ohm5 years ago
I guess I was a little miss-leading in pointing out the metallic pens. I was just pointing out there might be better type ink pens that could be used then the permanent marker pens to hand draw circuits for later etching. Maybe they would less likely be undercut by the acid.
KJ4ZVQ dcutter12 years ago
If they have metal in the ink, would'nt the etchant just eat the pen traces as well?
justinpruss1 month ago

Think the Industrial Sharpie would work even better? And how about Cupric Chloride? I just mix Muriatic Acid and Hydrogen Peroxide I think its 2 parts H2O2 to 1 Muriatic Acid.

indika2n7 months ago

when we use small marker pen to draw the lines, its really same as printed one!

relic19741 year ago
This gives me a great idea! I'm working on a laser etching 2 axis machine. though it will be some time before I get a chance to build it, this instructable made me think of a very handy tool for PCB etching when you don't need to use CAD software...

If I can rig up simple x / y manual control of the laser using small stepper motors, like those in CD drive optics, I can take a thin piece of aluminum and laser cut footprints for different components, trace widths, IC holes and spacing, etc. the same general idea as using stencils to draw letters on paper. actually they should market something like this.
i tried doing this before, it didn't work well to say the least the ferric went under the sharpie, and through the copper , leaving me with barely any traces all 3 of my homemade stompboxes didn't work, none of the traces stayed on, but i still tried anyways, so now i have $200 in wasted parts :\ not quite sure what i could do to salvage the stuff
get a desoldering iron. just curious... did you have black lines and did you let the ink completely dry for about an hour? I could see how the ferric chloride would just plow through traces made by a sharpie if they were put on there minutes before trying to etch it, for sure. and why didn't you take a voltage reader and measure resistance in ohms on a straight line / trace with the pin things an inch apart and see whether its conductive or not.
Perhaps you didn't make the traces heavy enough to resist the etchant. A fairly fresh sharpie would work the best, not a very used one that will no longer make a solid black line.
arduino man3 years ago
Can I use PCB Etchant Solution from Radioshack.

Yes, that is ferric chloride.
beehard444 years ago
i read you can use wax instead of sharpie... might make an 'ible next week
 Hi,
I used a  uniball pen instead of a sharpie. Would that work or will I need a sharpie???

Ohm (author)  shadowkiller4 years ago
I am not sure, I have always used a Sharpee, if you are willing to experiment try it and let us know, otherwise get a Sharpee and redo it to be safe.
I just tried and  It kind of worked. Most of it came off.
Oh well, Back to the drawing board.

Use any OHP or permanent marker. My electronics book says a pen you can use is the Edding 140S.
bobfit4 years ago
I have not been happy with the Sharpie pen as it sometimes washes away in the etchant, especially if you are using a foam brush to speed up the etching.
Nail polish works but it is difficult to get even traces. Recently I bought a Testors enamel paint marker (available at Michaels or maybe your local hobby shop). I sharpened the wide tip to a point and proceeded to draw the circuit. Works like a charm. For IC's paint a bar for the the entire pin row then remove the paint with a knife between pin holes.  I use a Radio Shack universal pc board as a drilling jig to locate the pin holes before painting. Use lacquer thinner to remove the paint. 
Ohm (author)  bobfit4 years ago
Great tip, I never really do the foam brush bit so I never noticed any problem with the sharpee in that way but the paint pin sounds like a good idea all the way around, I well have to give it a try the next time I do one. With your permission I would like to add the paint pin to the materials list, credited to you of course.
raykholo5 years ago
combining this idea with another tutorial--- would it be possible to transfer an eagle schematic onto the board using UV light, then following ur instructable of tracing it over with a super fine sharpie and etching it?
There would be no point. Might as well just use the UV for everything. You would gain nothing by using both.
Botfly7 years ago
What is the proper way to dispose of the toxic stew?
cirano Botfly7 years ago
I remember reading somewhere that used ferric chloride should be mixed with baking soda inorder to neutralize it and make it safe for disposal. (please feel free to set me straight)
Actually, washing soda, not baking. (Very different stuffs indeed ;-))
is washing soda also called baking powder? i always confuse baking powder and baking soda, so I am not allowed to bake...im a griller and a saute-er.
Washing soda is not baking soda is not baking powder!
Washing soda is sodium carbonate
Baking soda is sodium bicarbonate
and baking powder is a mixture of baking soda, a alkali, and a dry acid such as cream of tartar.

None can be substituted for one-another. However, you can make baking powder using the recipe above.
Baking soda is a alkali itself so the alkali doesn't do much but the dry acid will make it react as soon as it gets near something with a pH around 7 (or a pH that IS 7.)
and i can make baby powder with old dried babies
Ah! Thanks for the correction. That is completely different indeed. I wonder if someone can actually post the chemical reaction that shows the neutralization process?
I wonder if there's a way to filter and reclaim the copper from the etching waste, then re-use the ferric chloride. I've never etched pcb's, but this does sound like something that needs to be addressed properly.
put this in a dark colored bottle mix with water until on the brim of the bottle then bury it
You store it in a jar until it doesnt work anymore then you pour it down the drain with LOTS of water
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