P.O. wrote:
>
> 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?
>
0.8 dl would be 0.8 deciliters = 0.08 liters = 80 milliliters
Is that correct ?
Normal makeup concentration of ammonium persulfate etchant is 100 to 200
g/L and should be heated > 35°C for reasonable etching times. A fresh
solution at 65°C in a bubble etching tank will etch 36um thick foil PCB
material around 5 to 8 minutes. Sodium persulfate and ammonium
persulfate are practically interchangeable.
If the copper looses it's shine in first 30 seconds then the etchant is
working. Is that happening ?