Conformal Coating

The marine environment is salt-laden and humid, tough on uncoated PCBs. Conformal coatings are used to seal the board from atmospheric moisture and contaminants, greatly extending lifetime and reliability.

XREG-010 uses Chemtronics Konform AR and/or MG Chemicals 419D. Both are one-part acrylics that cure at room temperature and carry a UV indicator for inspection.

Acrylics are forgiving for rework (can solder through them), easy to apply via brush or spray can, and readily available. The weakness is solvent resistance. Gasoline, acetone, brake cleaner, MEK, and even IPA all soften the film, but we luckily don't expect unintentional exposure to any of these.

For rework, coating must NOT cover the obvious (any connector), but also the tiny hole in the BMP388 temperature/barometric pressure sensor. A tiny piece of masking tape works well as a shield.