Conformal Coating / LPKF Solder-Lac

At work we use a spray lacquer type stuff called Solder-Lac that we buy from LPKF. We use it to coat freshly milled bare copper PCB's to prevent them from oxidation. It takes a day or two to completely dry, but when you go to assemble or repair the board (weeks to months later) the copper is not corroded at all and the coating acts like a flux agent. LPKF of course claims this is something special that their coating does.

Question: Are there other coatings that do the same thing with the fluxing action when you heat the coating with a soldering iron? The LPKF Solder-Lac product is expensive ($20USD/6.6fl oz) and if it's just something else re-branded I would like to find the cheaper version. Thanks!


Paid Member
2007-07-17 2:35 am
Central Berlin, Germany
I use SK10 spray flux, of Kontakt Chemie / CRC industries ( It seems to be very similar (takes *at least* two days to fully dry). It is not to be used as a true sealant, though, it degenerates under influence of high humidity/temperature and then will not provide anti-corrosion protection. There, urethane based coating does better (but doesn't have flux support while still being "solderable", IME), it is also claimed it has better electrical characteristics.

Price (here in Germany) is ~7EUR/200ml (~6.6 fl.oz) or ~10EUR/400ml, which look quite a bit cheaper than the LPKF stuff. I don't know if it is available outside the EU.

- Klaus