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Removing deep vacuum sputtered silver from copper electronics grade copper masks

Currently I have a problem with removing deep vacuum sputtered silver from copper electronics grade copper masks. The process currently employed uses an aqueous hydrokollag barrier (wet graphite) which is hand painted on the copper mask to isolate silver from copper. This barrier allows electrical conduction to copper during silver sputtering. The silver removal cleaning process places the silver sputtered copper into an H2O ultrasonic cleaner for many hours. The silver separates slightly at hydrokollag barrier and then we score the silver creating a crack in the silver and peel mechanically removing large pieces of silver. The problem with this process is that sometimes the silver pieces adhere quite well to the designed copper angles and it takes hours to clean. Many times the copper mask edges are damaged during the mechanical. I have a couple of questions concerning this problem; I read in item number 26306 "Reclaiming Silver from Vacuum Capacitors" the individual who responded stated that both ways of removal whether it be Nitric and sulfuric Acid or Cyanide are extremely hazardous and dangerous to human health. I want to try and stay away from these hazards. Is there a chemical that can be added to the hydrokollag to improve separation of sputtered silver from copper mask parts? Is there a chemical and / or electrolysis process that can be used with a stainless steel ultrasonic cleaner to create an easier separation of sputtered silver from a copper mask part without damaging copper mask.

Michael Boyer
CD / DVD Manufacturer - Wesley Chapel, FL, USA
2005

Currently conducting testing using a BRANSON 5500 Ultra-Sonic Cleaner heated bath. Bath Contains NaOH 100% 3 volumes and distilled H20 one volume. The bath is heated to about 150' F and the Ultra-Sonic Frequency is 42KHZ. The smaller copper mask part(ID)with fresh chemical causes hydrokollag barrier layer (aqueous graphite) to soften and dissolve making NaOH solution dark and black. The silver on the copper mask blisters then breaks up into to small particles in about 25 minutes. The mixture looks like swirling silver particles in black clouds. Can only strip 3 masks total before silver debris and density in NaOH bath starts absorbing ultra-sonic waves prior to reaching copper mask part. Need to devise an appropriate filter system compatible with NaOH or an electrolysis method for removing metals from an NaOH bath. Are there any recommendations?

Michael Boyer
CD / DVD Manufacturer - Wesley Chapel, FL, USA
2005