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The Dutch Way

Neon techniques abroad

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Examining shop practices abroad can be quite helpful, especially if you specialize in handcrafted work. By doing so, you can learn and borrow some helpful tricks of the trade. However, keep an open mind when examining another shop’s habits and techniques — avoid being too judgmental.

This month, I’ll report on the techniques of neon manufacturer Steven van der Ven, who owns and operates "suspensie neon van der ven b.v." (Apeldoorn, the Netherlands).

In the Netherlands, neon is expensive. However, the quality of most Dutch neon tubes is much higher than that in the United States and, probably, the rest of the world. This higher quality results from different tube-manufacturing technology, which requires considerable labor and investment costs, which result in higher prices.

Neon-tube quality is based on tube lifetime and light-output maintenance. To achieve constant light output, the largest acceptable tube diameter — from the optical-appearance point of view — is selected for a neon sign. Thus, for covered channel letters a diameter of 18 to 22mm is standard; for large letters, diameters up to 25mm are used.

Dutch glasswork

Dutch neon shops use sodalime glass almost exclusively to create neon tubing. Contrary to lead glass, it readily liquefies and can be directed to flow into place. Working with large-diameter, sodalime-glass tubing requires considerable skill. Thus, the three-year apprenticeship of a neon glassblower in the Netherlands is equivalent to a scientific glassblower’s education. (Note: I’ve used the term "glassblower" because a Dutch glassblower’s education and work style are more like a scientific glassblower’s than a U.S. tubebender’s.)

The single-point, cannon-fire bench torch (Fig. 1) is a Dutch neon glassblower’s main fire source. Neon workpieces are large compared to those handled by scientific glassblowers. Thus, to have enough free space to move and rotate the work in the flame, the Dutch neon "bench" burner is mounted on a pole on a freestanding floor stand (Fig. 1).

Applying the glassbending technique common in the United States to bending thin-wall, large-diameter sodalime glass would create weak tubes, because the glass on the outer periphery would become too thin and couldn’t withstand the mechanical load. Thus, by making the glass flow to the outer periphery (Fig. 2), a Dutch glassblower can create a 90-degree bend, where the outside and inside wall thicknesses remain constant, as in a straight tube.

Keep in mind, such manipulation can’t be done by heating the glass one time. Plus, depending on a letter’s complexity, such a task may require three to five minutes.

Fluorescent coating

Another difference is the Dutch tube-coating process. As Figs. 1 and 2 indicate, only uncoated glass (clear or classic colors) is shaped in the Netherlands. Dutch glass shaping requires heating the glass to a liquid flow; if the glass is precoated by the manufacturer, the fluorescent powder will melt into the glass mass — causing the fluorescent powder to lose its fluorescence — and create stress.

As a result, using a process developed by the Philips incandescent lamp factory’s neon department in the 1940s, the glass tubing is coated after having been shaped. The unique Philips process applies the fluorescent powder in suspension to the inside of the bent tube.

This suspension, which comprises the fluorescent material, a glue-like binder and solvent mixture, is poured, shaken and carefully drained into a tube that has been carefully cleaned using special detergents, ultrasonic agitation and distilled water to rid any impurities. The binder provides just enough adhesion so that a very thin, uniform layer of fluorescent powder sticks to the glass wall.

The tube is then laid on its back side to air-dry, and the solvent evaporates with warm air, eventually causing the remaining surplus material to collect on the tube’s back side.

The next tube-coating step involves burning off the binder and sintering the powder onto the glass wall. In this step, the tubes are heated to 968

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