*Shown from left to right in the image above: ceramic nozzles, tungsten carbide nozzle, and boron carbide nozzle.
When selecting your blasting nozzle, you have various choices today. One should not confuse the type of nozzle with the often-found trade names given to them by respective manufacturers/distributors.
The most common type of nozzle is made from a light ceramic compound; these are usually white in color and are the least expensive nozzle you can get (about $4 to $9 depending on orifice size). This, however, also means that they wear fairly fast. The life span of such a nozzle is approximately 1 to 3 hours of continuous blasting.
The next step up is a usually dark brown/gray-colored nozzle made from tungsten carbide. These nozzles are made from an alloy of ceramics and metal powders and are much harder than the ceramic nozzles. This slows the wear of the orifice as the abrasive travels through the nozzle. These have a prolonged life span of up to 20 to 40 hours of continuous blasting. Cost for one of these nozzles runs between $36 to $48 each.
Next up in price is the boron carbide nozzle. Made up of elemental boron and metal, it is similar to steel but much harder. These are also dark brown/gray in color and are harder than the previous nozzle type. The makers of these nozzles list its life span, at continuous blasting, at about 200-plus hours. The cost of such a nozzle is between $120 and $180 each.
The advantage of more expensive nozzles is that they wear slowly, making it unnecessary to change nozzles while working. Since these nozzles keep their original orifice for long periods of time, they do not require increasing amounts of air from your compressor; this preserves your motor from excess wear and tear.
Also note that the life spans listed are for continuous blasting, meaning no stopping and starting as you work. This will make it a bit more difficult to verify the life span unless you take notes while working, listing all stopping and starting times.
-Ruth Dobbins, Your Professional Glass Consultant