My first PCB

Potential Health Effects of Ferric Cloride

mramos1 said:

Marks256,

I am new to the HCL and H2O2. Replace that with ferric chloride and I think you will find a lot of people here doing PCBs that way. So you bought the right stuff.

I am nervous about the muriatic acid now. Went online to see about clean the concrete with it, and it etchs the concrete. Bad fumes, it hits empty glass or water want to blow back on you.. I will try it once and get rid of it. $4 a bottle from Radio Shack sounds safter.

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If you think ferric cloride is so safe, read this:

Potential Health Effects of Ferric Cloride
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Inhalation:
Extremely destructive to tissues of the mucous membranes and upper respiratory tract. Symptoms may include burning sensation, coughing, wheezing, laryngitis, shortness of breath, headache, nausea and vomiting.
Ingestion:
Corrosive. Swallowing can cause severe burns of the mouth, throat, and stomach. Can cause sore throat, vomiting, diarrhea. Low toxicity in small quantities but larger doses (30 mg/kg) may cause nausea, vomiting and diarrhea. Pink urine discoloration is a strong indicator of iron poisoning. Liver damage, coma and death may follow, sometimes delayed as long as three days.
Skin Contact:
Corrosive. Symptoms of redness, pain, and severe burn can occur.
Eye Contact:
Corrosive. Contact can cause blurred vision, redness, pain and severe tissue burns.
Chronic Exposure:
Repeated ingestion may cause liver damage. Prolonged exposure of the eyes may cause discoloration.
Aggravation of Pre-existing Conditions:
No information found.

..And mixing your own chemicals is?

I don't think anyone plans on etching in a closet...

mramos1 said:

I am nervous about the muriatic acid now. Went online to see about clean the concrete with it, and it etchs the concrete. Bad fumes, it hits empty glass or water want to blow back on you.. I will try it once and get rid of it. $4 a bottle from Radio Shack sounds safter.

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Yeah, its really nasty stuff. It etches concrete quite well when diluted, it really chomps at it full strength. Put a penny in it undiluted and you will have flakes in a matter of minutes. I put a super rusty iorn horseshoe that had been in the mud for 50 or 60 years in it overnight and it took it right down to bare metal.

I think when I do get all the stuff to try it i'll do it at my machine shop with the ventilation fan on. I don't know that I really want that stuff in my house!

Would this be a perfect time to question my need for etching?

Crap! I just realized i don't have a laser printer! What can i do?

Marks256 said:

Crap! I just realized i don't have a laser printer! What can i do?

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Print it out inkjet and use a copy machine?

use a photocopier or a public library

Crap! I just realized i don't have a laser printer! What can i do?

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Or.... Save it as a GIF and email it to yourself at school or work and print it there. (Eagle imbeds the DPI in the file so it should print correctly)....

Is there a certain amount of time i have to put the image on the board from the paper?

I am just having also my circuit. I am using paint as a PCB maker this is one of the examples I am using. After creating it I printed it to a Acetate the one used in projectors. I ironed it on my PCB(you must let it cool before removing the acetate) and I itched it and drilled the holes and connected my IC's. For me, I prefer using paint because its easy. When I was soldering the IC's I encountered 2 pins connecting so I used a Soldering paste to avoid this. It is really important using a paste to avoid unwanted connections.

"paint" would work for simple projects, but an eeprom programmer requires A LOT of connections...

Marks256 said:

Is there a certain amount of time i have to put the image on the board from the paper?

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I've heard that you should iron it just after you print it for best results, but I printed mine at work and ironed it about 5 hours later with no problems. I had the same issue as you; no laser at home. Just make sure the laser is set for the darkest toner setting and not running in "econo mode"...

ikalogic said:

well, i prepare the copper board carefully before ironing the layout on it.

here is the sequence i use :

1-cut the board with 1 or .5 cm spare on the 4 sides, as heats usualy concentrate in the middle and is less at the end of the board.
2- scratch the board with sand paper, in 2 orthoogonal directions, till it brigh and shiny
3-use a clean towel and some organique solvant (i use "thinner"), and pass it on the board, each time changing with a new towel, until the towel is clean after you pass in on the board.
4-simply start the ironing process, taking less than 5 min with a 10X10 board.
5- leave the board with the paper on it in a bath of hot water for 5 or 10 min (preferably with some soab in the water)
6-remouve the paper by peeling it off, then with a tooth brush but try to be gentle using it!.

this is how i do it for more than 2 years now.

you have to adjust your printer the the maximum ink density.. (but i am sure you allready figured this out)
hope this help.

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Thankx Someuseful informations.Same way I did but when removing the paper by peeling off is the hardest part.the first layer in the paper can remove easily & the next layer is very hard to remove even with a toothbrush.It has got stucked.with the thumb pressure can remove but the edges get jammed.

paparts said:

(snip) It is really important using a paste to avoid unwanted connections.

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Please explain how using soldering paste prevents shorts, caused by solder bridges.

answers to questions and points raised in several postings:

using paint as a PCB maker

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it's possible but a lot of effort. I'd just get eagle (or some other schematic capture/PCB package). Eagle does several things that you can't with paint: verifying correctness, design rule checking, tracking schematic changes, exact scale, chip pads/outlines, ...

soldering paste prevents shorts, caused by solder bridges

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It doesn't prevent it but, in theory, you only apply enough so there is no excess which avoids bridging. In theory, anyway. The better way to avoid bridges is having a pcb with a solder mask. You can also use flux to increase the attraction of bare metal to solder and thus decrease the probability of bridging.

a number of people said:

ferric chloride vs HCB+H2O2

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Think about what you are doing - you're etching. That means to remove metal. You aren't going to find any etchant that doesn't come with a lot of warnings. If the warnings bother some one, they should take up knitting. FeCl is nasty stuff, Ammonium Persulphate (AP) is nasty stuff, HCl is nasty stuff, H2O2 is nasty stuff. On the use of HCl, be aware that the bubbles are hydrogen gas. It's lighter than air and can collect in pockets - explosive pockets. I wouldn't use this to etch and would have lots of ventilation if I did use it. FeCl is nasty because it stains most everything it touches and you can't see the progress of your etching. It's cheap, though. I personally use AP since it is fairly benign, doesn't stain much and is clear so I can watch it progress. More expensive, though.

Soldering paste

This seperates unwanted connection, it only stick on the bronze

paparts said:

This seperates unwanted connection, it only stick on the bronze

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I was tough that soldering paste was for plumbers and had no use in electronic assembly. (but I have used in an emergency)
The reason the normal solder with a rosin core is not flowing on the copper is;
the copper is not clean, copper oxidizes fast and most be cleaned shortly before soldering. I just shine it by rubbing it with a large art eraser until it shines. Then there are no problems with soldering or bridging.

Rolf said:

I was tough that soldering paste was for plumbers and had no use in electronic assembly. (but I have used in an emergency)

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Don't EVER use plumbers flux for electronics, it's highly corrosive and not in any way suitable. You can buy tins of proper flux for electronics soldering, which is fine - but it's only really used for fairly obscure projects, and not for solering components to PCB's where the internal flux in the solder is all you need (anyway, how do they get the cores of flux in the solder?.

But liquid flux is commonplace, for used with SM devices - and I even use it for larger soldering jobs, such as soldering an aerial socket back on a tuner - it helps the solder to flow, and go where you want it to better.

I haven't looked yet, but are there any good tutorials available for Eagle? I used it once, but then my HD crashed and i never got around to re-installing it. I did like it, though...

yes, there are several tutorials. google for them.

also, check out the al williams book. making pcbs at home (or some such title). He uses eagle throughout the book and it's a very good eagle tutorial.