There are three main types of foam letters for displays and for concrete casting. Read more about concrete casting here . The types are: 1. Indoor Wall Display Wording 2. Outdoor Wall Lettering 3. Large Free-Standing Display Letters for Exhibitions Foam letters are available either painted or plain/unpainted and are generally all made from expanded plastic foam. Some of the advantages of foam letters: Generally costs less than other materials, can be ready to ship in 1-2 weeks, very lightweight. Disadvantages: Made for temporary use*, can be damaged without care, adds to the landfill issues. *Foamed plastic can be affected by UV light (like the sun), damaged by moderate force and otherwise easily be broken if handled without care. Foam letters can be used as part of the casting form to make 'embossed' monuments, memorials, pavers and corner stones. Reverse-cast letters ready for monument casting. Painted for in/outdoors Indoor letters and wall displays can easily mark and ...