[Lab] Questions: 1) DIY PCB etching and 2) O-scope in lab?

[Richard Perrin]

I've no experience with it, but have come across this photoresist
method, using pre-sensitized boards and   hydrogen peroxide, vinegar,
and salt:
http://quinndunki.com/blondihacks/?p=351

No dangerous chemicals, other than lye in the photo developing solution.

The Veronica 6502-based computer she's working on and posting about at
that site is an interesting project to follow.

- Richard

On Wed, Jan 11, 2012 at 1:53 PM, Paul & Andrea Mumby
<themumbys at gmail.com> wrote:
> Here's my comments:
>
> FeCl3 etchant can be messy, but it's not too bad to etch with in the home if
> your careful with it.
>
> HCL+H2O2 etchant can be dangerous to mix if your not careful about it (HCL
> can be nasty to get on the skin, where FeCl3 will just stain it, and
> irritate it, HCL will cause major chemical burns). Once mixed the etchant
> isn't that bad though. It is still a stronger acid than FeCl3, and is very
> adept at dissolving proteins (flesh) so not super ideal to get on your skin,
> but at least you wouldn't be etching with it at full strength normally. Also
> mixing with any kind of Oxidizer (which in some cases H2O2 will act as) will
> gas off pure Chlorine Gas which is nasty stuff too... Even the low
> concentration hardware store Muriatic Acid you would buy would be strong
> enough for major chemical burns if not careful.
>
> That said the HCL+H2O2 Etchant is cleaner for the environment, it's
> renewable, and it etches a fair bit faster than FeCl3, and it's not as
> sensitive to temperature.
>
> I'm personally happy with FeCl3 in my etching, I don't heat it, I have a
> fairly cool basement and I etch at ambient temperature (15C-18C) and it
> takes me about 30min to etch a 4"x6" single sided PCB using the Toner
> Transfer method. I use plastic tupperware containers with a nice seal to
> store the etchant in, I drop the board in, seal it up good, and agitate it
> by slowly rocking the container back and forth by hand. When done I use a
> larger plastic tub to rinse the board off (And heavily dilute any waste
> etchant) before rinsing it down the slop sink in my laundry room. I get a
> couple dozen boards out of a container of etchant. Then I have to deal with
> the fun of disposing of it. (Heavily diluting, and neutralizing with diluted
> sodium hydroxide).
>
> Ultimately etching at home requires dangerous chemicals no matter which
> method you use. Care needs to be taken in storage, use and disposal to
> ensure your safety, and environmental impact.
>
> Another much cleaner and easier option is sending the job out to be done to
> a fab shop.
>
> One affordable option is Seeedstudio. They will do boards for a great price,
> and are good to deal with. Their basic service will do 5cm x 5cm PCBs, 2
> layers, with silk screen and solder mask. And it's only like $10 for 10
> boards, which is $1 per board. Really it's a fantastic price. 10cm x 10cm is
> only $25 for 10 boards. And you get the nice professional looking PCBs with
> holes drilled, solder mask, and silk screen layer on it too...
>
> Hope that helps some.
>
> - Paul
>
>
>
>
>
> On Wed, Jan 11, 2012 at 12:28 PM, Darcy Whyte <darcy at siteware.com> wrote:
>>
>> I've not had boards made by mail yet. What about those boards that just
>> have lots of holes? If the circuit is simple that's another way to do it.
>>
>> I'm betting someone will come forward with a suggestion of where to get a
>> board made. I don't think it's very expensive.
>>
>> Another list where people are into circuit boards and stuff is
>> OttawaRobotics.org.
>>
>> A metal detector is a great project to get kids into making things (and
>> electronics).
>>
>>
>>
>>
>> On Wed, Jan 11, 2012 at 12:22 PM, <eric.schmidt at rogers.com> wrote:
>>>
>>> Thanks Darcy;
>>>
>>> Yes, messy and fraught with the possibility of screwups, but I wanted us
>>> to do the "full DIY" process at least once.
>>>
>>> Who would you suggest for the mail-order route, though? I'm curious about
>>> the cost of that option.
>>>
>>> cheers,
>>> Eric
>>>
>>> ________________________________
>>> From: Darcy Whyte <darcy at siteware.com>
>>> To: eric.schmidt at rogers.com
>>> Sent: Wednesday, January 11, 2012 12:08:17 PM
>>> Subject: Re: [Lab] Questions: 1) DIY PCB etching and 2) O-scope in lab?
>>>
>>> I noticed an scope in the lab
>>> Are you bringing the project to the next modlab?
>>> etching sounds messy
>>> Perhaps mail order can solve that one?
>>> Or perhaps a DNC machine? Not the best method but it might be easier
>>> On Jan 11, 2012 12:01 PM, <eric.schmidt at rogers.com> wrote:
>>>
>>> So, I've bitten the bullet after lots of lurking on the list, and have
>>> initiated our first "dad and kids" electronics project (ok, it'll be vastly
>>> "dad with kids looking on")
>>> We're going to make this metal detector:
>>> http://makeprojects.com/Project/Treasure-Finder/1113/1
>>>
>>> I'm just wondering how many of you have done PCB etching using the
>>> toner-transfer method.
>>> After going through a bunch of youtube videos on the etching process,
>>> some of them mention the stinkyness/toxicity of the fumes from the acid
>>> bath. I bought FeCl3 etchant from Active, but now I'm thinking that maybe
>>> HCL+H202 would be better, as described here:
>>>
>>> http://www.instructables.com/id/Stop-using-Ferric-Chloride-etchant!--A-better-etc/
>>>
>>> Regardless of etchant, though, in mid-winter, doing it in the garage is
>>> probably out of the question due to the cold (or is it?) but I assume I have
>>> to ventilate the heck out of whatever space we use.
>>>
>>> any guidance on the etching process?
>>>
>>> Next question: for this project, you need to tune the reference coil
>>> using either an oscilloscope or a frequency-counting multimeter. Does the
>>> Lab have either of these? Cuz I don't...
>>>
>>> thanks in advance for any wisdom.
>>>
>>> cheers,
>>> Eric
>>>
>>> _______________________________________________
>>> Lab mailing list
>>> Lab at artengine.ca
>>> http://artengine.ca/mailman/listinfo/lab
>>>
>>>
>>>
>>
>>
>> _______________________________________________
>> Lab mailing list
>> Lab at artengine.ca
>> http://artengine.ca/mailman/listinfo/lab
>>
>
>
> _______________________________________________
> Lab mailing list
> Lab at artengine.ca
> http://artengine.ca/mailman/listinfo/lab
>