Homebrew PCBs

Sodium persulfate is a rather slow etchant, but it produces a very clean surface.  We used to use it as the basis for a chemical clean line prior to laminating photo resist.  

I assume you put in 5 ot 10% sulfuric acid in the etch.  No acid, no etch.
  ----- Original Message ----- 
  From: P.O. 
  To: Homebrew_PCBs@yahoogroups.com 
  Sent: Monday, November 01, 2004 7:27 AM
  Subject: [Homebrew_PCBs] Slow etching, Sodium Persulfate?



  Does anyone use sodium persulfate as etchant?
  I'm makeing my first pcb using toner transfer from kodak-paper. But the 
  etchant doesn't work very well.
  I use about 0,8 dl etchant for 4 dl of water@ca 50° in a plastic bowl 
  that and moved stirred it pretty much the first hour... The pcb is 
  about 4x3 cm big.
  Now it has been in the etchant all night and only about 1/8 of the 
  board has etched.
  Maybe the kodak-paper left something on the surface? I did iron it 
  about 60 seconds on both sides. To long?

  /P.O.





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