Conformal coatings are challenging. First, they are designed to be very durable and hard to remove. Then, there are many, many different types of coatings, and many are old formulations which require old solvent which are no longer widely acceptable. Let’s take a look at some good choices for more common applications:
Dow Corning and other companies produce very popular conformal coatings based on silicones. They offer great protection while being light, durable and easy to rework. Almost without exception, silicone coatings may be removed by either the VOC-Free Flux Remover — UltraClean™ or the No-Clean Flux Remover – VeriClean™. This product is based on siloxane technologies, so it is chemically very similar to most silicone conformal coatings. In one test with a large Texas computer manufacturer, No-Clean Flux Remover – VeriClean™ removed in two minutes a coating which had been taking 45 minutes to remove with more traditional solvents.
Acrylic coatings, like Humiseal 1B31, can be difficult to remove. Your best choice is the Heavy-Duty Flux Remover – SuprClean™. It is a formidable cleaner with a high Kb value. If it dries a little too quickly for this application, soak the parts in a bath of the solvents. Put a lid on the container so the fluid does not evaporate too quickly.
Urethanes are challenging to remove. Generally, a powerful, slow-drying solvent will work best, if anything works at all. Try the Uncured ExPoxy™ Remover as one option. Usually, these coatings can be removed with a good, long soaking bath in the solvent. Put a cover on the bath to control solvent evaporation.
Epoxy coatings are very difficult. There is no benchtop-safe chemical which can remove a cured epoxy coating, except physical abrasion. If the coating has not cured (hardened) the Uncured ExPoxy™ Remover will be the best option. Usually, these coatings can be removed with a good, long soaking bath in the solvent. Put a cover on the bath to control solvent evaporation.
Paralene is a military-style coating, very thin and rock-hard. It simply cannot be removed chemically.