Protective solder mask Fuzan 52-SR is a removable temporary masking resist used to protect connectors, adjustable components, IC sockets, and select board areas during reflow soldering, wave soldering, and conformal-coating application. Supplied as a white gel with 70% non-volatile content and a viscosity of 4000 mPa·s, it can be thinned with a small amount of deionized water (no more than 5% by mass) and mixed to a smooth, even consistency with a spatula or mixer. It cures at room temperature — with heat optional to speed drying — in as little as 3–7 minutes at 150 °C or up to 30–45 minutes at 25 °C, and its tough, high-strength film peels away in one piece without tearing or leaving residue, even after conformal coating (remove once the lacquer is tack-free, before full cure). It is applied by dot dispensing or brushing, is resistant to solvents, and will not dissolve when conformal coatings are applied over it. Fuzan 52-SR is developed and manufactured in Russia, supplied in 250 ml bottles or 30 ml syringes, and should be stored at 6–28 °C (never frozen) with a 6-month shelf life.