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Is the UV curable paint used for PCB etching the same UV curable paint used for making PCB solder masks? Some have different eBay descriptions but they're all in identical 100g black containers.

As far as I can tell, the only difference to making a solder mask is only doing the first development with sodium carbonate to remove the unexposed UV paint and then leaving the rest? (i.e. no ferric chloride / ammonium persulphate or sodium hydroxide)

Can I do multiple layers of solder masks? Can I use a second white solder mask over the top of the first green solder mask in place of silk screening to add the legend on?

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Etch resist used in PCB manufacturing is typically a photosensitive film laminated to the board. It's called dry film photoresist. here is a typical product datasheet showing all the processes.

Note the stripping process at the end- using caustics. It's almost impossible to remove solder mask after it cross-links, so I don't think it would be very suitable.

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  • \$\begingroup\$ Okay they must be different things then. Do you know if it's possible to do multiple solder mask layers? \$\endgroup\$ – Ashlyn Black Feb 13 '16 at 16:53
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    \$\begingroup\$ There is no reason why not, but it's not part of the normal process flow. It would expect it would be possible, at some premium in cost from a commercial board house. It is very easy to add a second UV mask print to a completed PCB using a silk screen process. \$\endgroup\$ – Spehro Pefhany Feb 13 '16 at 17:11

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