Hercules Boiler Solder makes strong lasting repairs on leaks in steam boilers caused by leaking joints or sand holes during installation, or older installations where corrosion, vibration or settling causes leaks and cracks.

I first encountered formic acid erosion/corrosion when our installed air conditioning and heat pump evaporator (indoor) coils began suddenly leaking refrigerant in 2008. These were not old coils either, and some had only been installed for a year when the issues arose.