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View Full Version : Episode 15: PCB Etching [Discussion]


eminemdrdre00
08-25-2007, 04:41 AM
Circuit Boards, nearly every modern electrical device uses them, but how do you make your own? David Randolph and Patrick Norton show you the path to success using ACID!

blazes816
08-25-2007, 04:48 AM
I knew Dave used acid.

tangerine
08-25-2007, 05:14 AM
I just want to say TY to Patrick Norton.
He is having WAYYY more fun on Rev3
Nice ta see ya!

ps:
David Randolph on the Soap Box was epic.
He is good people.

ezxen
08-25-2007, 05:37 AM
This was a nice episode i remember something like this on the SS back in the day . I would love to see more episodes like this .

sptlght
08-25-2007, 07:28 AM
no more soapbox please

sh1fty
08-25-2007, 07:45 AM
it was a cool episode, but they're too careful. i prefer using HCl (hydrochloric acid) to make the boards. it's not hard to find(most hardware stores have it), it's much cheaper and it's not too dangerous when you mix it with water. you should probably use distilled water but tap water should work if you don't have any distilled water. you should mix it so that you have about 1/3 acid and 2/3 water, but it's not an exact science. if you think it's ready just try it. if it's too fast just add more water and if it's too slow add more acid. if you're brave enough you can take your pcb out of it with your fingers without gloves, but anything plastic will work ;) you don't have to soak it in water or anything, just take it to a sink and wash it. you can also use steel wool to get rid of the "black part" after you're done with etching. oh, they forgot to mention, make sure your copper board is clean before you print your circuit on it. if it's not clean use sandpaper or steel wool. when it's clean you should avoid touching copper with your fingers if you're not using gloves because your fingerprints will slow the acid down a bit. i think that's it :) have fun

chaoticprout
08-25-2007, 07:55 AM
Soapbox = epic. Great episode ;)

optimus
08-27-2007, 02:19 AM
Indeed the soapbox was epic. Another great episode guys, keep it rollin'!! Patrick: Good to see you enjoying one of your new gigs!

speed
08-27-2007, 03:48 AM
I wish they had shown the actual process of etching the boards. They talked about it, and showed the tools you need, but not the actual process. You don't watch a cooking show where someone says "here are your eggs, flour and such, you mix them together and instead of showing you how to make it, we'll just show you the finished cake". Other than that, not bad.

dbovine
08-27-2007, 01:18 PM
I think I am with sptlght on the soapbox. Not that I dont appreciate the rant, because i do, I think the rant was great but felt the soapbox part might be a tad corny. With that said I dont have any other ideas on how to segment in the rant while still trying to keep it appearing as a side note.

Keep up the good work

britontour
08-27-2007, 07:04 PM
I loved the soapbox rant. However, there are other PCB design tools out there that are free. Two that I know of are:

KiKad: http://www.lis.inpg.fr/realise_au_lis/kicad/

gEDA: http://geda.seul.org/index.html

There are others out there if you search, but these are the two best know.

bigron18
08-28-2007, 03:03 AM
When I was an electronics major in college and we learned to make circuit boards (1990-91), after we etched and cleaned off the resist, we would dunk the board in another solution which would tin the copper. I do not remember why we tinned, just that we did. Is there a good reason to do this or not to do this?

I had an idea I'd like to see on Systm... I'd like to see a multi-part section where you actually design AND build a complete project. So far, you've touched on many aspects, like how to set up a work station, different useful tools, basics on how to use them. Now, we've seen how to etch a board. After maybe a few more little base knowledge, start the project, incorporating everything. I would suggest a multi-part segment, allowing time to focus on important aspects. Just as a suggestion for a project, how about the Digg button? Episode 1 of the multi-part segment would be on how to design the PCB layout for ease and efficiency, but include a PDF or similar document on the Systm.org website of the project. Also, include a parts list (and approx. prices) that followers will need to order or pick up from a store, as it may take a week or so for them to arrive. Another episode would be actually transferring a printout of the PCB onto the copper board and etching it (similar to this episode, but specific to this project). If staggered a week or so apart, this should allow people following along to catch up or re-watch an episode a couple times before getting too far behind. The next episode is drilling the holes and possibly trimming the board down to size and any other preparation before placing circuits. The next episode is soldering down all the components. Next, re-cap how to program the AVR and trouble-shooting any potential problems. Lastly, design a project case to house the component. Obviously, this is just my "top of the head" suggestion. I'm sure David, Patrick and others from Revision3 can refine this a bit.

I haven't done this kind of project in 16 years (boy does that make me feel old all of a sudden). I think following along on my own will help remind me of what I used to know. It would be fun and educational.

suzq
08-28-2007, 09:00 PM
Dave needs to etch his soapbox, lol!

blazes816
08-28-2007, 09:06 PM
I agree with bigron. A multipart full project would be EPIC.

aheroslastresort
08-29-2007, 12:19 AM
love the soap box!!!!

jimxugle
08-29-2007, 05:37 PM
Instead of putting loads of effort into using a brillo pad to remove the sharpie from the circuit board, you could add more chemicals to the mix and use rubbing alcohol.

Caution: Using rubbing alcohol will lead you to the startling realization that black sharpies are indeed purple.

-JimXugle

tempesta
08-30-2007, 06:46 PM
1. the soapbox was gold....i hope to see dave rant about more things. booyah.
2. this was interesting stuff, coz when I was doing circuits in high school they built the boards for us....coz you can't trust 15yo's with acid....so i wanted to know the process.

top shit fellas.

burne
08-30-2007, 11:42 PM
the path to success using ACID!

Actually, you didn't. Both etching-agents used are salts. Salts are fairly harmless. Ferric chloride won't do much harm to your skin, except leave nasty brown stains. Ammonium per-sulfate is mildly irritating to your skin. Ferric chloride is used in medical application and sewer-treatment. Ammonium per-sulfate is used in plastic-production.

Don't splatter and don't wait to wash off any spilled liquid. Gloves are a good idea, but don't panic over relative harmless salt-solutions.

As to the guy advising to use HCl: *DON'T*. Hydrochloric acid *is* a strong acid. It will eat your skin, bones and table. It will produce gaseous HCl which will eat your airways. If you insist on using HCl: etch your boards outside the house, well away from anything and anyone. Compared to ferric chloride and Ammonium per-sulfate it is the really bad stuff which will make you suffer. Preferably don't use it. It's too dangerous to keep around in the house.

Another note: the developer used for printed circuit boards is mostly Sodium hydroxide. Caustic Soda, lye. Again dangerous stuff, before diluting it to the proper concentration for developing boards. You can buy caustic soda-free developer. More expensive, but given the much lower risks involved in handling the stuff, much preferred over concentrated lye solutions in a bottle.

sh1fty
08-31-2007, 02:22 PM
HCl acid is usually 30% acid and 70% water when you buy it, so when you mix it with water you get about 10% acid which is pretty harmless. it's much easier to find because almost every hardware store has it. i know people who've been using it almost every day for more then 15-20 years and are still breathing, so ething by a window should do the trick ;)

huntr2
09-01-2007, 11:22 PM
I'd just like to add this link to the discussion http://www.fullnet.com/~tomg/gooteepc.htm

It is a great guide the printing and etching using the 'toner transfer' method but with normal photo paper rather than special paper. I have tried it myself and managed to print and etch a PCB for a simple PIC programmer. The paper I used was some generic labeled 'Super Gloss' 135 gsm and it worked perfectly.

Here are some pictures of what I created. Sorry about the quality but I only had my PSP GoCam! to hand.

http://i73.photobucket.com/albums/i207/huntr2/pcbfront.jpg

http://i73.photobucket.com/albums/i207/huntr2/pcbback.jpg

For those interested, I used this site for the JDM Programmer schematic http://www.janson-soft.de/pic/pic.htm

The PCB was designed with Eagle from Cadsoft (http://www.cadsoft.de/)

speed
09-02-2007, 04:12 PM
Actually, you didn't. Both etching-agents used are salts. Salts are fairly harmless. Ferric chloride won't do much harm to your skin, except leave nasty brown stains. Ammonium per-sulfate is mildly irritating to your skin. Ferric chloride is used in medical application and sewer-treatment. Ammonium per-sulfate is used in plastic-production.

Don't splatter and don't wait to wash off any spilled liquid. Gloves are a good idea, but don't panic over relative harmless salt-solutions.

As to the guy advising to use HCl: *DON'T*. Hydrochloric acid *is* a strong acid. It will eat your skin, bones and table. It will produce gaseous HCl which will eat your airways. If you insist on using HCl: etch your boards outside the house, well away from anything and anyone. Compared to ferric chloride and Ammonium per-sulfate it is the really bad stuff which will make you suffer. Preferably don't use it. It's too dangerous to keep around in the house.

Wow, so many mistakes I don't know where to begin.
First, Ferric Chloride is acidic and highly corrosive, so it WILL do damage if it gets on your hands.
Second, Ammonium Persulfate is corrosive and a severe oxidizer.
Third, it doesn't matter if something is a "strong" or "weak" acid. All that matters is the concentration. If you have diluted HCl (strong acid) and concentrated H2S (weak acid), the H2S will do more damage.

Seriously man, at least take a high school chem class before you go on acting like an expert.

edottjr
09-03-2007, 12:17 AM
Argh!

Okay Acids are very tricky chemicals to work with. You all should really consult a chemist before presenting information about chemicals.

I am a chemist I work with this stuff everyday, we have a PCB board shop at work, and it was scary watching you guys handle this stuff.

Seriously, the materials used in etching PCB boards can really cause serious bodily harm, and environmental damage.

Every time I go into the local hardware store I shudder as I realize how easily people have access to potentially dangerous chemicals.

One of the things you did not mention is that if the chemicals you use in making PCB boards are not disposed of properly they can accidentally be mixed with other chemicals with disastrous consequences. This is not a joke.

I highly recommend that anyone interested in making PCB themselves, take a class at their local community college or technical institute. You will learn how make the boards in a safe environment and learn how to handle the equipment and materials safely before trying your hand at them at home.

Really guys, have some thought for the safety of your audience.

Regards,

Ed Ott
Chemist
ed_ott@hotmail.com

edottjr
09-03-2007, 12:19 AM
Wow, so many mistakes I don't know where to begin.
First, Ferric Chloride is acidic and highly corrosive, so it WILL do damage if it gets on your hands.
Second, Ammonium Persulfate is corrosive and a severe oxidizer.
Third, it doesn't matter if something is a "strong" or "weak" acid. All that matters is the concentration. If you have diluted HCl (strong acid) and concentrated H2S (weak acid), the H2S will do more damage.

Seriously man, at least take a high school chem class before you go on acting like an expert.

Yes FeCl3 is a deliquiescent material. It will actually react with the water in air to form HCl Hydrochlirc acid, which will burn you!!!

Not to worry though, I have found that stupidity in the long run is self correcting...

edottjr

tweakerxp
09-04-2007, 02:36 AM
I remember making PCBs in high school with almost no safety instruction whatsoever. We would print our layout on a laser printer and affix it to the copper board using a t-shirt press. After an acid bath (can't remember exactly what the solution was, pretty sure it was ferric chloride, but I know we switch to something from something else that worked much better.) we ended up with some great looking boards.

PS. We often did touch up with sharpies, and even dry-erase markers worked alright :)

dkphybr
10-19-2007, 02:42 AM
Another option is DipTrace (http://www.diptrace.com). It's not open source but there is a limited free version. The paid versions are not very expensive. The support has been good so far. It's still kind of new so it's far from perfect but it is way more intuitive than EAGLE--which is one of the most user-hostile programs I have ever experienced.

whoisscott
11-13-2007, 09:38 PM
this is my first time and i'd like to try but, um, where can i buy the copper boards?

I've seen it recommended that you use a guillotine to cut the boards. Is there any thing else i could use to cut the boards?

wizmaster
11-13-2007, 09:56 PM
this is my first time and i'd like to try but, um, where can i buy the copper boards?

I've seen it recommended that you use a guillotine to cut the boards. Is there any thing else i could use to cut the boards?

You can get boards in different sizes. Try for sites. Some of them have a nice collection or post a question for the best one. Not sure myself.

jibberish
11-13-2007, 10:12 PM
Skip the chemical etching of boards entirely. That's my opinion. Too many hazards, your finished boards will never be able to meet the quality of a board that was laid out in with CAD, and you cannot do via's, fine-pitch layouts, and multilayer boards. Here are two great websites that have some FREE very simple, easy-to-use, quasi CAD software that you can use to design boards on a computer. Then you send them your files and they send you the boards for a pretty descent price.

http://www.pcb123.com/

http://www.expresspcb.com/

I have only used ExpressPCB, and I was completely satisfied with the product. They have a deal where you can get three double-sided boards (http://www.expresspcb.com/ExpressPCBHtm/SpecsMiniboard.htm) for $51, as long as they are 3.8 x 2.5 inches, and some other restrictions as well. Thats a pretty descent price if you ask me.

If you want to get into the whole circuit design thing a little more, then I highly recommend EAGLECAD (http://www.cadsoft.de/) by CADSoft.

I disagree with David Randolph on this one. :) I find it easy to use.

There is freeware version (http://www.cadsoft.de/freeware.htm) that has some limitations, and a non-profit version (http://www.cadsoft.de/nonprofit.htm) that has less limitations. I have used the freeware version, and it is some serious software.

Best of luck!