Etching questions

Thread Starter

Electroguy86

Joined Nov 20, 2012
26
http://m.instructables.com/id/Stop-using-Ferric-Chloride-etchant!--A-better-etc/

Question. First off I'm new to pcb etching. Always used perf boards. Tried this solution and love it! First few boards I etched took minutes with a fresh solution. I had to make another solution and dropped a board in it. It took nearly 20-30 minutes to etch a small board. Tried to mix another solution like instructable says and same thing. Slow etch. Why? Should the board be dry after rubbing paper off or could paper from the laser etcher still be on there slowing etch time down? Also, light? Could light really slow it down that fast? Heating? Can that speed it up? And I know about agitating it. Thanks!

Oh, this is using muriatic acid and hydrogen peroxide
 

Thread Starter

Electroguy86

Joined Nov 20, 2012
26
Hmm.. I wonder what I'm doing wrong. Maybe their is some paper residue on the board im not seeing. i have been doing a mixture of 2 parts H2O2 and 1 part HCL. What if it was 1:1? The pic is of one of my first boards. Slow to etch but did do a pretty good job I think.
 

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Wendy

Joined Mar 24, 2008
23,415
Heating is important. If you have a hotplate I would preheat the liquid to lukewarm. It dramatically speeds etching, for any etchant.

If you read that procedure I posted you will note the gloves and small piece of sponge. Again, it improves the results and speed dramatically.

Agitation works better for FeCl3, while the sponge works better for the H2O2/Muriatic Acid IMO.
 

Markd77

Joined Sep 7, 2009
2,806
Just a note on the board, the holes that come through from the other side to the ground plane are going to be hard to solder because you end up heating a large area of board. Most PCB software will have a special pad which looks the ones here. It will make it easier.

hole.gif
 
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