Help my Gobo is burning!

Actually, all gobos burn to some degree. If a Gobo Projector unit is new, or the gobos are new, oils can burn off and create a small bit of smoke, this is normal.

What can be a problem is, that if the lamp in your Gobo fixture is not properly focused in the gate, which can create a hot spot, or uneven burn.

The newer instruments are genreally cooler than the older lighting instruments, but you should still make sure that your lamp is bench focused, to avoid a hot spot, or a cocentrated burn area. The attached pictures show 3 different gobo burn types.

The bottom picture shows a burn from a older traditional unit, showing a nice complete burn across the gobo.

The middle picture shows a lamp that is out of focus and is creating a hot spot. A hot spot from a non focused lamp will cause your gobo as well as you gel to burn out early.

The top picture shopws a typical burn from one3 of the newer cool beam units which create far less heat than older units.

The typical gate temperature of an older 1k unit, was over 1700 degrees at the gate, newer cool beam units, have dropped the gate temperature to less than 500 degrees.

Is there a standard size Gobo?

Is there a standard size gobo is a good question. The answer is no. The problem is that gobos differ in size for each lighting instrument. There are certainly some gobo sizes that are more popular than others, but there is no standard size Gobo. Each lighting fixture takes its own unique gobo size, although there are some crossovers in gobo sizes, most instruments take their own unique size.
When sizing a gobo, there are two measurements that are crucial, IA (image area) or VA (viewable area), and OD outer diameter. There are many websites online that provide lists of which lighting instruments take which gobo size and what the exact measurements are.
There must also be a match between the gobo size, and the correct sized matching gobo holder.Like the lighting fixtures, every gobo has it’s own size gobo holder. A good example of this is the ETC Source Four, which can take either a A size gobo holder, or a B size gobo holder, and also accepts a glass pattern holder, so not all gobo holders are the same, or a standard size for each light.
Below are some common gobo size names:
A, B, D, E, Q, M,D....