Subject: | |
From: | |
Reply To: | TechNet E-Mail Forum. |
Date: | Tue, 23 Nov 1999 07:37:42 PST |
Content-Type: | text/plain |
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Hey Rudy,
Next time buy an ad! If this is not thoses blatant advertising post, then I
do not know what is. And by the way I have used your resist stripper.
It sucked.....
>From: Rudy Sedlak <[log in to unmask]>
>Reply-To: "TechNet E-Mail Forum." <[log in to unmask]>, [log in to unmask]
>To: [log in to unmask]
>Subject: [TN] Tarnish after resist stripping
>Date: Tue, 23 Nov 1999 09:37:28 EST
>
>I do love it when someone asks a question that we are real knowledgeable
>on.
>Thank you.
>
>Tarnish on Copper after stripping is endemic to resist stripping. It is
>made
>much worse by buildup of Copper in the stripping chemistry. In other
>words,
>most strippers will not tarnish when new, but begin to tarnish as they are
>used, and Copper builds in the sump.
>
>The problem is cureable by using a resist stripping chemistry with the
>proper anti-tarnish in it. Most resist stripping chemistry has 250 ppm of
>Copper when the stripper is dumped. It is possible to get resist strippers
>that will not build up more than 30 ppm of Copper for the same number of
>panels stripped, and average less than 2 false defects per 18" X 24" panel.
>This has a nice added benefit of keeping the Copper in the rinse waters so
>low that they usually do not have to be treated, and can legally be put
>right
>down the drain.
>
>Many stripper chemistry vendors have resolved this issue by simply going to
>high volume feed and bleed, thus turning the sump over often, and keeping
>the
>dissolved Copper levels low. This is great for the chemistry vendor, but
>expensive for the PCB fabricator, and not required with the proper
>anti-tarnish chemistry.
>
>As you probably have surmised, we are one of the vendors who can supply
>resist strippers with the proper anti-tarnish properties.
>
>Rudy Sedlak
>RD Chemical Company
>[log in to unmask]
>
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