Spray application coating
This coating can be completed with a spray aerosol or dedicated spray booth with spray gun and is suitable for low and medium volume processing. The quality of the surface finish can be superior to all other methods when a trained skilled operator completes the process, as long as the circuit board is clean and the coating has no adhesion issues. The coating application may be limited due to 3D effects but masking requirements are more "shield" than "barrier" since the penetration is less effective. However, the lack of penetration can be an issue where coating is desired to penetrate under devices.
Spray applications can be one of the most cost effective ways of applying conformal coating as it can be done on the bench top if necessary for small rework and repair jobs, or scaled up to be done in spray booths for medium scale production.
One of the key attributes of atomised spraying is giving excellent tip coverage to components. When conformal coatings are applied to a PCB they have a tendency to slump. The first layer of a coating can give a thin edge on the corner of components. This can be countered with a second coat through double dipping or over brushing but this is a repeat process and may not be acceptable. To counter this problem the technique of atomised spraying can be used.