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I am interested in putting that nice green / red soldermask on the PCBs that I make at home. The problem is I can't find a lot of information on it, like where to buy it, etc. Do any hobbyists actually do this, or is it only for the pros?

CLARIFY:
I am interested in this technique not only to protect my board once it is complete, but also so I can give it a professional look. I understand fully that I don't 'need' it for hobby type applications, but I am still interested in it. Is this stuff that can actually be bought in reasonable quantities? Is it very expensive, etc. Does anybody know?

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Surely you can do soldermask, if you already mastered making PCBs using photomasks. Material for soldermasks is also UV-sensetive, so you expose & develop it and that's it.

But unless you are using reflow soldering at home :-) , there is no much sence. You can solder even small-mid size BGA's without soldermask - just flux & practice.

Or if you badly want soldermask for BGA in small quantity - you can just take capton material, and manually make all required holes and then glue it to PCB.

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    \$\begingroup\$ Kapton tape is a good idea for this project. I think I'll try cutting some on my laser engraver to see how this works! Do you know where you can get broader sheets of the stuff? \$\endgroup\$ Feb 26 '11 at 21:56
  • \$\begingroup\$ Unfortunately no :-| \$\endgroup\$ Feb 26 '11 at 23:19
  • \$\begingroup\$ You have a laser engraver? Then, problem solved! Engravers will remove solder mask and leave the copper/tinplate untouched. Just spray-paint the board and laser away the paint on the pads. \$\endgroup\$
    – markrages
    Feb 27 '11 at 0:00
  • \$\begingroup\$ @Mark - It sounds like you've done this before. What sort of paint should be used? It would have to be high-temperature and non-conductive, right? \$\endgroup\$ Feb 28 '11 at 17:31
  • \$\begingroup\$ Just regular enamel spray paint. You should probably measure conductance yourself, just to be sure. \$\endgroup\$
    – markrages
    Feb 28 '11 at 18:42
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Soldermask is a special layer on PCBs that is meant to keep the solder onto the pads. This is only useful if you want to wave solder. I am not aware of a way to do that at home, because you need to have a mask to keep it off the pads. It is usually applied in a screen printing or photoimageable process. If you make your own PCBs, they will not be fine enough to profit from this.

If you want to add a shiny protective layer after soldering, you may want to try conformal coating. Perhaps something like http://www.electrolube.com/docs/conformalmain.asp?id=76

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    \$\begingroup\$ Soldermask is useful for several other reasons than making it easier to "machine solder" (I assume you mean wave): including but not limited to reducing corrosion, controlling impedance, and reducing bridging between fine pitch pads. \$\endgroup\$
    – Nick T
    Feb 26 '11 at 0:20
  • \$\begingroup\$ But those thing can be done with conformal coating as mentioned? \$\endgroup\$
    – XTL
    Feb 28 '11 at 18:14
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As previously mentioned, conformal coating is a pretty good approach. We have some 10 year old PCBs here which are still in good condition. This is how we used to do it:

  • Polish the PCB with Brasso until it looks beautifully shiny.
  • Clean the PCB with methylated spirits.
  • Buy some Liquid Latex.
  • Use a small stick to apply a dot of latex to each pad that needs to be soldered.
  • When the latex is dry, spray on the conformal coating.
  • Lightly bake the boards until the coating is dry.
  • Now peel off the latex dots.
  • Clean the boards and you're good to go.
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  • \$\begingroup\$ The best answer/information I could find since the past two days. Simple and clear. Tank you very much! \$\endgroup\$ Jan 4 '17 at 23:03
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This process describes using pebeo vitrea (a stained glass paint) as a solder mask. I have not yet tried as I'm still working on perfecting my clothes iron technique, but the results that site shows are very promising.

Better yet, there's an ebay store that sells a whole bunch of different colors for a pretty cheap price.

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If you're just looking for protection for the board, you could go with a spray-on coating. This tests a few different ones for marine use. Since they are all designed for wet/salty conditions, they should protect the boards well under any normal conditions.

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