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Subject: Re: [Homebrew_PCBs] liquid tin as mask?

From: guja <guja2001bg@...>
Date: 2007-04-11

tin-ELECTROplated-mask is suitable (only) for ammonium-persulfate-etching.
(NH4)2S2O8

DJ Delorie <dj@...> wrote:

More random thoughts...

I was thinking about plated-through holes and how big fabs do them.
You drill, plate the holes, ∗then∗ etch. They use a tin electroplate
as the mask. Can we do something similar?

The idea:

Drill and electroplate the pcb.

Use a standard photomask, but in negative - expose where you want
copper to stay. Develop. Not sure if TT would stand up to the tin
plating.

Immerse in "Liquid Tin" to tin-plate the copper that's going to
remain.

Strip the mask and etch the board.





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