Hello Paddy,

What is typically done before making a copy from a nickel master (I am
assuming that you are plating nickel after the silver flash) to avoid
this type of sticking is to slightly oxidize the surface of the
master.  I'm not sure what works best with nickel, and you can
probably look it up in a chemistry handbook, but one place to start
might be a dilute hydrogen peroxide.  Once a thin nickel oxide is
formed, it is chemically stable and will allow multiple copies to be
plated and separated from one master.

Brad Cantos
brad.cantos@holage.com
http://holage.com

On Jun 11, 2009, at 1:18 PM, li xuan wrote:

> Hi,
>
> I am using the shipley 1805 to coat my plate to make hologram. My
> process is
>
> 1. coat the glass with 1805, then let it air dry for about 4 days.
> 2. make some hologram on it.
> 3. silver spray
> 4. put into electroforming tank grow to a thick shim.
> 5. seperate the shim from the glass. used NaOH 5% to remove the
> photoresistor from the silver layer.
>
> Now the problem I got is when I put the silver shim back into tank
> to make a copy. the copy is always got stick and lots of water
> strip. People think it is because the photoresistor is not
> compeletly removed from the silver layer or maybe the silver layer
> gets destroyed by NaOH. Does anyone have any idea why this happens?
> Do I really have to bake the photoresistor to make it easy to
> remove? Can anyone recommend some remover? I try the shipley 1112A.
> seems does not work at all. Thanks!
>
>
> Paddy
>