October 2, 2012

Thin line between thin lines and spiders - II

Modifications that can be considered to make an airbrush better capable of spraying fine lines are the following:
  1. taller trigger
  2. lower needle rocker spring tension
  3. polished needle
  4. processed water
Taller triggers have to be moved over a slightly longer distance than short standard triggers to make the needle travel the same distance. This means that the artist has finer control over the needle movement It is made visible in the image below.

Tall trigger modification

Over the full travel range there is an increase of about 4 millimeter using tall triggers compared to standard triggers. Of course the full range is never used in spraying fine detail and the actual usable gain is less than one millimeter in detail spraying. But as was referred to in the previous blog entry, trigger motion is critical when spraying with severely diluted paint and ultra low air pressure. Experienced artists know that often merely increase in or decreasing the index finger's pressure on the trigger will result in a wider or finer line.

A good description of the advantages of trigger modification you will be able to see in this Youtube video. My take on this mod is visible in the image below, where I glued a Dremel felt pad onto the (already relative tall) trigger of the Infinity using a Bison kit. The rugged felt feels much more comfortable to the index finger than the Infinity's standard trigger. First impressions of its handling are that the needle polishing and trigger mods make the Infinity approximately spray as fine as an unmodified CM SB. I always test mods on the Infinity first, before applying them to the Iwata Custom Micron SB.

Infinity trigger mod

Which brings us to the second point - lower needle rocker spring tension. Mounting a good quality softer spring adds to the fine control of the index finger over the trigger movement and postpones fatigue of the index finger. Some artists just cut off a piece of the standard string (upto 1/4 th of the total length). But using an entirely different spring is also an option, although it requires a lot of research to find a spring of the proper dimensions and tension.

Polishing needles I already described in this blog entry and the processing of water was explained in this blog entry. These modifications combined will make airbrushes spray finer lines while allowing the artist better trigger control, which results in a more gradual variation of the dispersion of paint, than they are capable of straight out of the box.

Besides these hardware and medium modifications however there are also exercises and diets that improve the artist's control over his or her motion. I will write about these matters in an other entry.