glass splashbacks

I’m not sure how to prep the surface but I would recommend you use opti-white low ionised glass. Because normal toughened glass has a green tinge which can ruin the colour applied on the back.

3mm is way too thin. 6 - 10mm toughened is best. Normal glass has a high iron content and will give a green tinge to whatever is applied to the back of it (white especially).

Starfire glass has less iron content and will not affect your chosen splashback colour.