What do I need to know about the Letralite when creating sandcarving stencils?

The bulb is the heart of the Letralite unit, so to speak. Without the bulb, there would be no exposure. Not all bulbs are created equal. This is not a normal fluorescent light, but a UV light bulb.

One important factor in choosing the right light is the wattage of the bulb. You can find the wattage information directly on your light bulb; it is printed on one end of the bulb. This is good to know if you need a replacement bulb. 

The bulb fits into the cradle on either side of the body and attaches with two pins on each end. First, you place the bulb into the cradle, and then gently turn it until it comes to a natural stopping point; this is called a bayonet fitting. What you may not know is that the bulb comes on when you turn the timer on, but it is really the ballast inside the body that starts the light. When your unit is new, this happens pretty instantaneously. 

As you keep working with the unit, and if you are paying attention to it, you may begin to notice that there is a brief delay before the light comes on. Often this delay is visible by a brief flickering of the light before it goes steady. As you keep working with the unit, it may turn into quite a few seconds before the light comes on steady. This is a problem, because it will change your exposure times and may mean a bad exposure of your material. You may be able to adjust your exposure times for this situation, but eventually you are better off replacing the ballast in the unit.

Another thing you that most are not aware of is the fact that the bulb will lose its intensity over time. You may need to adjust your exposure time to compensate for that loss of intensity. If you do not wish to monkey around with that, it is best to replace the bulb. The bulb will at some point quit working, which is the definite time to replace it.

   —Your Professional Glass Consultant

Ruth Jan 2018

Ruth Dobbins

With over 40 years in the glass business, Ruth Dobbins offers experience in all glass-etching techniques as well as in fused and cast glass. Ruth holds a master’s degree in art and has been a partner in an art glass wholesale supply and studio company in Europe, which also placed great emphasis on a training program, before joining forces with her late husband Norm. You can reach Ruth by email at or by phone at 505-473-9203.

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