One of the many challenges that can also be intimidating is when it comes to detailing the shuttle's lower thermal protection tiles. I have seen some rather innovative method involving painting over a mesh to attempt to get the tile look, and some even went to the extent of using small strips of masking tapes (a lot of work there). The problem here is that all those tiles are not a blanket flat black or dark grey, but rather a combination of very small brick patches with varying dark to light tones.
The Thermal Protection System (TPS) tiles serves as a barrier that protects the Orbiter during atmospheric re-entry when temperatures can reach a searing 1,650 °C (3,000 °F). They also protect the shuttle from the heat and cold of space while in orbit. Each type of TPS had specific heat protection, impact resistance, and weight characteristics, which determined the locations where it was used and the amount used.
Infra-red scans of a shuttle's atmospheric re-entry shows an uneven distribution of heat throughout it's lower hull during re-entry. This in turn will produce more wear and tear at certain areas. Hence depending on the tile conditions, some will be eventually replaced. This explains why certain areas of the lower hull are seen with patches of fresh black areas (replacement new black tiles) while others looked really worn out but still there. Here is an example of tile damage on a shuttle.
More after the jump.












































