[chbot] Anyone making PCBs?

[Mark Beckett]

Hopefully in plain only for Andrew.

When I was etching my own (using photo resist board), we used to heat 
and adjitation to help the etching process.
We used ammonium persulphate, which is a little more friendly.

http://www.surplustronics.co.nz/shop/product-SA0056.html

or

http://www.globalpc.co.nz/Electronics/Hardware/Prototyping-Boards/Product-Specification-H0802.aspx

Electroflash sell all the bits, but don't list the etchant, so they 
would also be a source.


Find an old saucepan, (or from a local supplier) and use warm water.
You can also use the double boiler method to indirectly heat the etchant.

Probably best you don't do it in the kitchen.
You can keep the solution and drag it out again if need be.

I have used Huntsbury for production, they are very reasonable, andd can 
handle a wide variety of source.
I suggest you do your own drilling, but make sure they etch the hole, 
otherwise its a nightmare.
http://www.huntsbury.co.nz/index.html

Mark


Andrew Errington wrote:
> On Tue, May 31, 2011 16:05, Richard Jones wrote:
>   
>> Kind of you to post the details Andrew,
>>
>>
>> I've made several attempts at the toner transfer method using .020 inch
>> tracks and 0.020 inch gaps and failed miserably. I don't recall how I did
>> the cleaning, stainless steel cleaning pads I think, so maybe the
>> additional detail is in the acetone. What size tracks and gaps are you
>> using? I finally gave up and used photo sensitive PCBs instead. With your
>> encouragement it deserves another try :-)
>>
>>     
>
> Hi Richard,
>
> I don't know what size I'm actually using- whatever are KiCAD's defaults. 
> I just measured one of the traces on the board and it looks like 0.5mm
> track/space, so probably 0.02"
>
> Visually, all the lands are separated (I did a flood fill to reduce how
> much copper needed to be removed) so I'll see if I can actually solder
> 1206 parts and a SOT-23 without bridging the gaps.  I might be being a bit
> ambitious.
>
> The thing about it is that you can inspect the toner transfer before you
> etch.  It's frustrating when it doesn't work, due to smudging or poor
> adhesion, but you can just wipe it off and start again.  It's sufficient
> to know that one works, therefore more are possible.
>
> As for the etchant, the ingredients are easier to get than Ferric Chloride
> (and slightly less nasty), and extremely cheap.
>
> I'd be happy to discuss it in more detail off-list, but there's not much
> more to say.
>
> Keep the copper clean.
> Use the blackest toner setting.
> Don't move the artwork when you're ironing.
> Don't push too hard.
> Be careful with the chemicals- wear gloves and goggles, and add the Acid
> to the Water, the way you know you oughta.
>
> Best wishes,
>
> Andrew
>
> PS I'll be trying again soon, but my next board needs some holes drilled.
>
>
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