September 8, 2012

Why every airbrush artist should have a microscope or magnifying glass

Allow me to first state that I'm aware of the fact that most airbrush artists struggle to make ends meet and that some of the options discussed in this blog entry are too expensive to purchase. But hang on, those that have to survive on a tight budget often tend to be the ones that are creative as hell. All you find in this article can also done by hand, using just a piece of fine grained sanding paper (1000 - 3000), perhaps some polishing paste and a cheap magnifying glass. It just takes more time and control of hand movement, but it most certainly is doable!

Airbrush needles are important parts of the guns. If their bent you can not spray correctly, because the jet of paint and air mixture that the airbrush is disturbed. If their scratched you will get tip dry in no time and the airbrush does not spray nicely, because paint will flow into the minute cavities and build up from there since paint is made to adhere.

What happens beyond your capacity to see? I got a USB microscope today that allows me to see what is actually going on in the area of the needle's tip. Below you see a magnified capture of the needle of the Iwata Custom Micron SB I recently bought. I sprayed one A4 size portrait with it that contains 8 drops of Holbein Aeroflash paint:

Iwata CM SB's needle after one portrait and 8 drops of paint

I also captured the needle of my trusty old Iwata HP-BH after 8 years of abuse. I must add to this that I've began polishing this needle with Johnson Silver polish - a process not yet finalized (since it takes a lot of time I do the polishing in various stints). Before I began polishing the BH's needle looked like a moon landscape surface under the microscope. It still sprayed nicely, but the polishing seems to make a huge difference. Especially the tip dry reduced; I have to clean the needle tip between paint refills at a lower frequency:

Iwata HP-BH's needle after 8 years of (ab)use

Polishing around the needle's tip area is particularly difficult and time consuming, probably since the steel is to some extent flexible and therefore neutralizes some of the (cautious) pressure applied during polishing. I will explain the polishing in an other blog entry later. The minute differences in coarseness of the two needles' surfaces, makes a difference. The spraying of the CM SB is beyond compare - Iwata has made big steps in a few years and succeeded in improving the quality of its (already excellent) airbrushes even further.

As a comparison I also captured the needle of an Infinity that did not spray fabulously. Here is why:

Harder & Steenbeck Infinity's bent needle
The microscope image makes it clear why the Infinity was not behaving well. Air  and paint molecules are taken for an abrupt D-tour while they prefer to travel in a straight line (the principle of inertia).

After repairing the needle the Infinity behaved noticeably better. Below is the image of the needle bent straight again (sort of). This was a quick fix by placing the needle tip under an angle against a hard surfave (a stack op paper) and rubbing over the tip with the back of my index nail while rotating the needle:

Infinity's needle (somewhat) straightened again

The needle cone surface of the Infinity is quite smooth actually, but it will roughen faster than the Iwata needles, because the material of the Iwata's needles is of a better quality - they are harder, more difficult to bend. The Infinity was rarely used I must add for the sake of completeness. The spraying result is less than that of the Iwatas.

Below is an image of the needle of the new generation Paasche V#1 (without the adjusting wheel directly in front of the trigger) that did not spray well, I regret to say. I was always a huge Paasche fan, but their new generation of airbrushes are in no way comparable with the excellent older generations. Today I only use Paasche's Turbo for very fine detail and controlled spattering. It is an older generation Turbo from the previous century, by the way.

New generation Paasche V#1 polished needle

The Paasche V#1 does not spray well. The needle blocked straight out of the box, because the siphon paint cup's stub was too long... After grinding off enough material to not obstruct the needle, the needle travel is still not smooth. And here's why:

New Generation Paasche V#1 Airbrush Tip and Nozzle

Although not clearly visible in the above image, because it is difficult to operate the microscope and hold the object below it simultaneously. The nozzle and rocker assembly (in which the needle is held and that is moved forward and backward by trigger action) are not centered properly; the needle is continuously stressed (slightly bent). If I wiggle the airbrush while looking down its internals from the tip, it is visible that the nozzle and are off center. This is the result of inaccurate machining in the production plant, which leads to unpredictable behaviour of the airbrush gun.

I used a Bresser USB microscope that magnifies between 20 and 200 times and allows me to store images in my laptop. This way I can compare needle's surfaces from before and after polishing and to see in which areas polishing did not catch on.

Bresser USB microscope

A smoothly polished needle point surface, will result in better airbrushing since the paint and additives have less grooved and irregular surface to adhere to, which causes the airbrush gun to clog and spray terribly and unpredictably. In the old days Paasche used to sell polished needles; that was before the quality of their tools deteriorated due to poor management decisions. In those days they still produced the magnificent, exotic Paasche Turbo and V1 that the great Alberto Ponno used, although he modified it and each airbrush came with a little sheet showing the fine line testing of the tool. Such proof of quality control testing is not included with the brand's products today. Alberto meticulously polished the needle tip and cut off a tiny peace of the spring to make handle movement softer which allowed more accurate control. He also used solvent based automotive paint, that flows better than common acrylic paint. It required him to use a good extraction system, but the quality of his art are beyond what is ever seen in the airbrush world. Paasche's current line of airbrushes has nowhere near the quality of the superb and very affordable tools they made back in the day. But polishing needles of any brand you can do yourself with tools of modest cost. It will surprise you how big of a difference polishing needles makes.