“Traffolyte” is strictly the name given to a particular type of hard multi-layer engraving sheet that is rarely used these days. The name itself has become a generic term for ‘engraving material’. Commonly today, soft engraving plastics are used as they are easier to machine and most suit the laser process. Engraving material is typically about 1.6mm or 0.8mm thick. Some specialty materials are thinner some thicker materials are available. Materials are rated to be ‘indoor’ or ‘outdoor’. The outdoor type have a top surface that better resists fading and degredation by sunlight and water.
Engraved signs can be fixed by pins, rivets, screws or double sided tapes. Plastic drive pins are commonly used on electrical switchboards where the absence of an internal metal retaining nut eliminates a potential risk should the nut become loose. Double sided fixing tape is very commonly used.
The best fixing tape is about 0.8mm thick, has an aggressive adhesive and used a foam back that conforms to the substrate to which it is stuck. Paper thin fixing tapes are available with very aggresive adhesives, however they rely on good surface contact and that the engraved item and the substrate be flat. For ease of installation of pins or rivets, engraved labels should have thin fixing tape in addition to the fixing holes. This allows the label to be positioned and fixing holes drilled later using both hands.
For metals, the common machinable grades can all be engraved. Leaded brass sheet specifically for rotary engraving is available. Grades 304 & 316 stainless steel can both be engraved. Stainless steels may be subject to an environmental staining when installed outside. Aluminium that is placed outside needs to be fully anodised after engraving, the pain filled as required.
Failure to do this will result in corrosion where unanodised aluminium is exposed to the air. The practice of installing dissimilar metals in contact should be avoided when fixing metals outside. An insulating layer between a metal sign and a different metal support with stainless steel screws is best. Use brass screws with a brass sign. Never use plated steel screws outside.