- Fairness
- The absence of Low Frequency, High Amplitude unevenness in the surfaces of the model. Fairness is the most
glaring of the surface defects and shows up as distorted reflections. Unfair, distorted reflections are one
of the most visible clues that a subject is a model and not a 1:1 scale prototype.
- Waviness
- The presence of Low Frequency, High Amplitude unevenness in the surfaces of the model.
The common causes of waviness are warped parts, sink marks and uneven assembly. Causes
distorted reflections which are a major "tell" that the subject is a model and not a
real car.
- Smoothness
- The absence of Medium Frequency, Medium Amplitude unevenness in the surfaces of the model.
- Roughness
- The presence of Medium Frequency, Medium Amplitude unevenness in the surfaces of the
model. The two most common forms of roughness are "orangepeel" and overspray.
- Shininess
- The absence of High Frequency, Low Amplitude unevenness in the surfaces of the model.
- Dullness
- The presence of High Frequency, Low Amplitude unevenness in the surfaces of the model.
The common cause of dullness is sanding and polishing swirls.
- Sink Marks
- Artifacts of the injection molding process or, more accurately, the cooling down process.
A Medium Frequency, High Amplitude defect commonly filled with a solvent putty. Sink marks
are almost always visible on the opposite side of a piece where the thickness
changes abruptly.
- Frequency
- How often surface defects occur every centimeter.
- Low frequency waviness averages around 1 cm but can manifest
at 10-15 cm in larger scales. In a real car, low frequency waviness is the result of sloppy bodywork.
A model should have no waviness.
- Medium frequency roughness occurs around the 1 mm level for orangepeel down to the
sub-.1 mm level for overspray. Orangepeel on models would scale to be golf ball sized
defects on real cars. There is no way that orangepeel scales to any real effect in the
1:1 world. Very bad orangepeel on a 1:1 car would best be duplicated by overspray/dry
coat on a scale model.
- High frequency dullness occurs below the .1 mm level and is caused in model car finishes
by polishing swirls. By carefully controlling the level of shininess one can best duplicate
the various finishes of different eras of paint technologies. Too much shininess looks
wrong on a 1950s race car.
- Amplitude
- How deep surface defects are.
- Polishing
- Polishing achieves smoothness by removing unevenness in the surface. Very smooth equals shiny.
- Waxing
- Waxing achieves shine by adding material to the surface and is used to fill the smallest
surface defects like polish swirl marks. Waxing also protects the finish from dulling caused by handling or the elements.
- Orangepeel
- A paint defect in which dry coats are over coated, building a surface that resembles
the texture of an orange. Orangepeel can be corrected only by sanding smooth before
adding more paint. You can not add coats of paint to orangepeel in an attempt to average
out the defects; instead the defects will become larger and softer. 1:1 scale cars can
have orangepeel finishes and this defect is common on lower cost cars and cheap paint
jobs. Since orangepeel on a model and orangepeel on a 1:1 scale prototype are caused by
the same problems in paint application, orangepeel on a model scales to outrageous proportions.
If a model's orangepeel were scaled to the full size care the car would appear to be
covered with golf balls. Orangepeel is never an acceptable finish on a model and scales
to no real paint effect on real cars. Orangepeel is a major "tell" that the subject is a
model and not a real car.