Etched house number

Actually its not 'etched' - it's sandblasted - a 'resist' of adhesive film is produced with the desired pattern cut out and this is then applied to the glass - in this case to 6.4mm clear laminated safety glass. It's then subject to a stream of 'sand' fired at it in an air-jet. The effect is similar to acid-etching. The sandblasted surface is then treated to help stop dirt accumulating. All manner of patterns may be produced on glass in this way.