Pyrography letters

My mum is a childminder and currently has children fascinated by letters -usually picking out their initials on road name signs on the school run. Anyway my mum decided I should do her a set of numbers and letters for the garden for them to spell with. 1 hour and 1 burnt finger later she has a lower and uppercase alphabet and a set of numbers. Now my sister, who's training to be a teacher, wants a set...