Sealing and 'Finishing Off
Genuine 23.5 kt or 23 kt gold leaf does not need to be sealed on exterior surfaces. Gold less than 23 karats has enough Silver and/or copper belended into it that these lower karat levels will tarnish, and therefore require a clear coat sealer.
It is generally recommended not to seal the gold in exterior applications, which is why it is recommended to use a 23 karat or higher gold content in your leaf. Sealers tend to break down or become milky/hazy, within 3-5 years. Unsealed 23kt or higher gold leaf can last 20- 30 years unsealed , if properly gilded.
However, it is sometimes desired to seal high traffic areas that have been gilt outside.
For interior use on gold and imitation metal leaf you can use the Dux 'Acrylic Topcoat' - (available in High gloss and Semi-gloss).
'Acrylic Topcoat' is a non-reactive, premium water clear sealer for genuine and metal leaf. Made from acrylic copolymers, Acrylic Topcoat provides protection from abrasion, water and ultra violet light.