Homebrew PCBs

Sodium Persulphate does not etch unless it is heated.  I have used the sponge with Ferric Chloride but most of the times I etch indoors without a hood it was too dangerous.  If you try the sponge thing you have to use a hood.  

I have not tried the sponge with Sodium Persulphate.  I have not had and undercutting problems that I noticed.


--- On Fri, 6/26/09, jc805sb <jc805sb@...> wrote:

From: jc805sb <jc805sb@yahoo.com>
Subject: [Homebrew_PCBs] Heating etchant: Re: “Dragon’s Blood” resin reduces undercut?
To: Homebrew_PCBs@yahoogroups.com
Date: Friday, June 26, 2009, 5:22 AM











    
            
            


      
      --- In Homebrew_PCBs@ yahoogroups. com, Daniel Johnson <a3v03v0@... > wrote:

>

> I switched from ferric chloride to sodium persulphate (MG Chemicals).  It is a much easier to handle are requires somewhat less care.  

> 

> I often etch single PCBs in a glass bread pan sitting on a foam rubber block while read mail.  A slight rocking of the pan is enough to keep the etchant moving.   I heat the etchant to about 130 degrees prior to starting.  Depending on how worn out the etchant is I may have to reheat.

> 

> One of these day I should make a real etching tank. 

> 

> The heavier the copper is the more you will have undercutting. This post on Electrotech has some images of a PCB I was working on a while back.  Compare the edges to what you are getting.

> 

> http://www.electro- tech-online. com/chit- chat/86683- cricut-2. html#post674243

> 



How are you heating the etchant?



Have you tried "sponging" the surface or not bothered with

trying it?



Also, do you keep your boards etching copper up, or copper down.




 

      

    
    
	
	 
	
	








	


	
	


      

[Non-text portions of this message have been removed]