Primers & Sealers
A brief understanding of the role of primers is helpful when choosing a primer.
1. Priming creates a surface with even absorption so topcoats dont appear patchy. Bare substrates or dirty walls usually have variations in their absorption level and without a primer this can show through in the topcoats as uneven colour and varying sheen levels.
2. Priming makes topcoats go on easier and spread further. Hence omitting a primer will not necessarily save on the overall cost of a job.
3. Priming increases topcoat adhesion. This may not be noticeable at first but can mean peeling paint in the future. Specialised primers such as Zinsser Smart Prime are used to adhere to glossy or hard to stick to surfaces.
4. Primers can enhance topcoat colour. Hence a coat of primer is useful when trying to cover strong colours. It is also common to tint primers grey, or half strength, under dark coloured topcoats to help give the colour more opacity.
5. Priming can be used to seal in stains such as mould, watermarks, smoke, oils, tannins, efflorescence and rust. These are specialised primers such as Zinsser Smart Prime and Metalfix.