The PCB's arrived yesterday in the mail, and Etching thoughts.

A project log for Inexpensive Lightweight Speech Recognition

A mostly hardware based solution suitable for micro controllers and other small systems.

thundersqueakThunderSqueak 08/22/2016 at 08:041 Comment

Well, the blanks did anyway. I know I could have just ordered this from a board house and been done with it, but what fun is that :) I am going to be using a toner transfer method to create the board layouts. I have not decided on which etching method I will use. In the past I have readily utilized Ferric Chloride. I am looking at other options however that may have less of an environmental impact. One possible solution is to use cupric chloride which can be reused. There is a nice article on it here!--A-better-etc/?ALLSTEPS

Before I jump into mixing chemicals listed on a website, I plan on talking to a friend of mine who is a chemistry professor at the University of Alaska to see what he thinks about the above solution and if it really is "more friendly".

For those who are not familiar with toner transfer PCB etching,

Those of you out there may say "why bother with all this, why not just order them?" Part of that is cost, I can etch many PCB's for a few dollars in components. The other reason is that this is a hobby and how I spend my free time. I enjoy the entire process of creating an object and much of it is about the journey. Without the journey, you don't learn. Learning is where the most enjoyment comes from.

I will get images up later after the board is etched as well as the results of the initial testing.



Ted Yapo wrote 08/22/2016 at 13:16 point

I still etch boards using toner transfer sometimes; it reminds me of developing film back in the good old days.  For the past few years, I've been using hydrogen peroxide and either hydrochloric acid or 6% vinegar (slow).  One of my chemistry professors used to say about waste products: "dilution is the solution,"  but I think that's fallen out of favor lately :-) I've wondered if you can evaporate the used etchant, then reduce it back to metallic copper with a torch (outside) so that it can be safely sequestered in the normal trash, but haven't done the research to see if that makes sense.

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