Kind of you to post the details Andrew,<br><br>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 :-)<br>
<br>Richard<br><br><div class="gmail_quote">On Tue, May 31, 2011 at 5:35 PM, Andrew Errington <span dir="ltr"><<a href="mailto:a.errington@lancaster.ac.uk">a.errington@lancaster.ac.uk</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;">
Hi everyone,<br>
<br>
Have you ever wondered if the 'toner transfer' method of making PCBs<br>
actually works? Have you ever wondered how you can get the chemicals<br>
needed for etching at home?<br>
<br>
I am pleased to report the answer to the first question is yes! And the<br>
second one is easy.<br>
<br>
Sorry to those of you who have blazed a trail and done this already, but<br>
I've always wanted to try for myself. For a long time. This weekend I<br>
got started and last night I successfully etched my first board!<br>
<br>
There are hundreds of websites describing the process in detail, but in<br>
case anyone is interested I'll summarise how I did it. Sometimes it is<br>
necessary that 'someone you know' has done it to be the catalyst for you<br>
to try it yourself.<br>
<br>
Anyway, here are my key points:<br>
<br>
1) I used KiCAD to draw a schematic and design my own PCB. I'm making a<br>
simple voltage detector which lights a warning LED when the voltage on a<br>
battery pack drops below a threshold. All the components are SMD.<br>
2) Print a mirror image of the artwork on a laser printer. There are two<br>
key points here (three, if you count mirror-imaging).<br>
2a) Print onto cheap glossy paper. I am using a supermarket flyer. The<br>
paper is thin and flimsy, but has a shiny surface.<br>
2b) In the printer driver set the toner density as high as possible (this<br>
might be set by a 'contrast' or other setting).<br>
3) Clean the copper-clad board really well. *Really* well. I am using<br>
the green pan scouring pads (without sponges). After that, I clean the<br>
board with acetone (I am using nail-varnish remover). Make sure it's<br>
really clean!<br>
4) I use a clothes iron to transfer the toner onto the surface of the PCB.<br>
5) I let the board cool, and put some warm water in a bowl with a drop of<br>
washing up liquid. I drop the PCB into the water and wait. After a while<br>
the toner paper will come away. After that I soak and rub the rest of the<br>
paper away. The toner should remain stuck to the board.<br>
6) If all is well you will have toner adhered strongly to your board.<br>
Touch up any small problems with a Sharpie permanent marker or a needle.<br>
<br>
You are ready to etch.<br>
<br>
It works for me! But, it's very tedious to get it right, so persevere<br>
(step 4 is deliberately glib). If you get a poor result you can wipe the<br>
toner off with acetone and start again.<br>
<br>
For etching I am using Hydrochloric Acid 12% (also called Muriatic Acid)<br>
and Hydrogen Peroxide 3%. I am mixing 50/50, but this will change for<br>
different concentrations. (Do this in a well-ventilated area, and wear<br>
gloves and safety goggles, and read up on handling precautions). It takes<br>
about 20 minutes to etch the copper away.<br>
<br>
After etching you can use acetone to remove the toner before soldering.<br>
<br>
I take no responsibility for damage to your laser printer or anything else<br>
you own, or for injuries sustained playing with nasty chemicals. I have<br>
skimmed over a lot of detail, so please check the web for more in-depth<br>
info.<br>
<br>
Today I will try and solder the components and see if it actually works.<br>
<br>
Best wishes.<br>
<br>
Andrew<br>
<br>
<br>
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