Glastar G-3 Manual

Glastar G-3 Manual

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Glastar G-3 Grinder
Owner's Manual



The power cord of this machine is equipped with a three-prong (grounding) plug which mates with a standard three-prong (grounding) wall receptacle to minimize the possibility of electric shock hazard. Have the wall receptacle checked by a qualified electrician to make sure the receptacle is properly grounded. Where a standard two-prong wall receptacle is encountered it is the personal responsibility and obligation of the customer to have it replaced with a properly grounded three-prong wall receptacle.


Usage of adapter plug.

Because of potential safety hazards under certain conditions, we strongly recommend against the use of an adapter plug. However, if you still elect to use and adapter, where local codes permit, a temporary connection may be made to a properly grounded two-prong wall receptacle by the use of a UL listed adapter which is available at most local hardware stores.

CAUTION: Attaching adapter ground terminal to wall receptacle cover screw does not ground the machine unless cover screw is metal, and not insulated, and wall receptacle is grounded through house wiring. Customer should have the circuit checked by a qualified electrician to make sure the receptacle is properly grounded. When disconnecting the power cord from the adapter, always hold the adapter with one hand. If this is not done, the adapter ground terminal is very likely to break with repeated use. Should this happen, DO NOT USE the machine until a proper ground has again been established.

Use of extension cords.

Because of potential safety hazards under certain conditions, we strongly recommend against the use of an extension cord. However, if you still elect to use an extension cord, it is absolutely necessary that it be a UL listed 3-wire grounding type extension cord.

Unplug your machine:
A. Before making any repairs - (Note: We strongly recommend that any servicing be performed by a qualified person.)
B. Before cleaning.



OUTSIDE USA (818) 341-0301 ·  INSIDE USA (800) 423-5635
FAX (818) 998-2078  · WEBSITE

Eye protection.

When operating the grinder, always protect yourself against eye injuries from flying glass. Either wear safety glasses or use an eye shield that mounts over the grinder's cutting head. Many users prefer the Glastar Eyeshield because it eliminates glass chips flying toward the face. It is available from most dealers as an option


In the carton, you will find the grinder and two additional items: a plastic splash guard and a packet containing an extra sponge and an allen key. The U-shaped splash guard attaches to the rim of the machine behind the cutting head. And, the allen key is used when changing or adjusting the cutting head.

To operate the grinder, you need only add water. It is not necessary to completely fill the reservoir. Add enough water - about one cup - so the water level is even with the bottom of the cutting head. Then, dip the sponge in water and squeeze it several times to make certain it is thoroughly wet. Replace the sponge in its pocket behind the cutting head, and turn on the grinder. As the cutting head turns, water is pumped into the sponge, keeping it soaking wet. The wet sponge keeps the diamond surface of the cutting head clean and cool. Never use the machine without first checking the water level and making certain the sponge is in place behind the cutting head. If you use the diamond cutting head dry, you will considerably shorten its life.

The cutting head slings water as it rotates. The splash guard catches most of this water and returns it to the reservoir. Do not overfill the machine. The higher the water level, the more water it will sling. Once cup is more than adequate.

When you start to grind, push the glass against the cutting head with firm, even pressure. The diamond surface cuts better and lasts longer with heavy pressure against it. Excessive pressure will not harm the diamond cutting head or slow the motor.

Some manufacturers suggest the use of an industrial coolant to protect the diamond head. Glastar does not recommend or discourage the application of a coolant. Coolants may prolong the life of the Glastar diamond head by 10 percent, but their costs far outweigh the money saved. In addition, coolant creates a mess.

If your finger touches the diamond cutting head when it is rotating, it will feel smooth. The diamond surface is not nearly the hazard to your fingers as is a belt grinder or a silicone carbide grinding wheel.


The diamond cutting surface of the head is 1/2 inch high. Glastar has installed the head so that the full 1/2 inch of diamond extends above the working table. If all the glass you grind is 1/8 inch thick or less, you will only use the lower one-fourth of the cutting surface. When that area dulls, lower the head another 1/8 inch and so forth. This will allow four surfaces; each surface should last approximately 50 to 75 hours, a total of 200 to 300 hours of grinding from one head. If you grind 1/4 inch thick glass, you lower the head 1/4 inch to change to a new, fresh surface. This gives you two grinding surfaces per head.

It is difficult to quote a specific number of hours that the diamond cutting head will last. Like sandpaper, it does not wear out all of a sudden. Instead, the cutting head gradually begins to dull. The head's durability depends on the type of glass you are grinding and your definition of dull. The 50 to 75 hours per surface is an estimate. Some claim more than 100 hours per surface, while others change to a fresh surface after 10 hours. Of course, you should expect far less life if you are grinding rocks.

Never grind any metal with the diamond cutting head. This will make the diamond surface unusable for glass in a matter of seconds.

To replace the diamond cutting head or to lower it, loosen the set screw near the top of the head with the allen key. The loosened head will slide up and down on the motor shaft with ease. Each time you reposition the cutting head, Glastar recommends the application of a lubricant, such as Vaseline, to both the motor shaft and the cutting head. When retightening the set screw with the allen key, make certain the head is set against the flat side of the motor shaft.

Ask your dealer about other sizes and grit cutting heads for your Glastar Grinder.


The grinder's only moving part is the electric motor which has permanently lubricated ball bearings. No maintenance is required, but you should periodically clean the top of the machine.

After using the grinder for a short period, you will find that a very fine white paste, made up of glass particles, collects at the bottom of the reservoir. This glass will also collect in the sponge and will eventually inhibit the movement of the water. Therefore, after every hour of use, remove the sponge, hold it under a water faucet, and squeeze it several times to rinse it clean. Every four hours, clean the reservoir of ground glass.

To clean the reservoir, unplug the machine and remove the white plastic work table by lifting it straight up. Use a wet paper tower or sponge to remove the glass paste. Snap the table back into position, plug the machine back in, and add water. You are now ready to grind glass again. No other maintenance is necessary.


The finely-ground glass that collects on the white plastic work table can scratch smooth, soft glass, such as 3/16 inch 1/4 inch plate, and some antique glasses. If you are working with soft glass, frequently remove the white work table and rinse it off. To be absolutely certain that you do not scratch the glass, place several strips of masking tape on the bottom of the glass to raise it off the table.

If you use a paper pattern when grinding the glass, water from the cutting head will get it quite wet. If you intend to make two projects from one set of patterns, let the paper dry out before attempting to grind the second set. After the paper dries, it will resemble its original shape and size. However, the paper patterns do shrink after getting wet several times.

For instance, if you are working on a Worden lamp. where the same set of patterns are used six times, Glastar recommends making a second set of patterns. Use each one only three times. Better yet, make original patterns from a sheet of acetate or mylar, these sheets can be used over and over again.


Model G3 & G4

This machine operates on standard household current (115 volts, 60 cycles, single phase, ac). The power consumption is 1.5 amps at full load.

Model G31 & G41

This machine operates on standard household current (220/440 volts, 50/60 Hz, single phase, ac). The power consumption is 0.8 amps.