Humidity therefore plays a major role in the shelf life of the abrasives. But temperature is also an important factor when it comes to storage, shelf life and quality of your abrasives.

An optimal storage climate ensures that the abrasives can be used without damage or loss of performance until the expiry date.

Storage and conservation of your abrasives

The ideal storage temperature of your abrasives is between 18 and 22 degrees, at a relative humidity of 45 to 65 %. Both the user and the distribution channel are responsible for the ideal storage conditions. It is the manufacturer's responsibility to package the abrasives in such a way that they are least vulnerable to air conditions.

In well-conditioned rooms, this packaging is sufficient. If you work on location or if the humidity in your warehouse is high, it is advisable to store the abrasives in a well-sealable box.

Influence of moisture on the abrasive material

Fiber discs

Fibre discs in particular are susceptible to warping. That is why these discs are more often packed in moisture-resistant bags. When the packaging of fibre discs is open, you can keep the discs flat until use by storing them in a special holder.

When humidity is too high, the lower layer of a fibre disc absorbs moisture. As a result, the fiber disc warps towards the grain, which is at the expense of the quality of the work and the life of the fiber disc.

When the humidity is too low, the bottom layer will dry out. The abrasive dries out, becomes brittle and crumbles.

Grinding and cutting discs

The shelf life of cut-off and deflashing wheels is also mainly determined by their moisture content. Discs exposed to high humidity after manufacture not only lose their original service life but can also become a safety hazard when directly exposed to water or water vapour. The age of the products plays a less important role here.
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Proper storage is important for the preservation, warranty and performance of our abrasives. And therefore also for the safety of the user

Surface-mounted cut-off and deflashing disc:

Both the cutting disc and the deflashing disc fall under the so-called synthetic resin-bonded products. This means that the wheels are made up of a combination of resin (binder), fillers and abrasive grains. A glass fibre network (4) provides extra reinforcement, stability and safety.

The metal ring in the middle (3) shows the expiry date. You may not use the disc after this date. This has to do with the binding of the grinding wheel. The grinding material is held together by a binder. After the expiration date, there is a greater risk of shattering or crumbling. So keep a close eye on this date! Above you will find more information on the storage and storage life of cut-off and deflashing wheels.

Hardness of a cut-off or deflashing wheel

The material to be machined

The hardness of a grinding wheel is determined by the binder used and by the added fillers. The binding hardness is indicated by a letter. The classification goes from A to Z, where a hardness A stands for a very soft disc and a Z for an extremely hard disc. In determining your choice of hardness, the starting point is the material to be machined.

In general, if you need to edit softer material, use a disc with a harder binding. A harder disc will have a longer tool life, but is less aggressive than a softer one.

With a soft bond, the grain will break out sooner and a new grain will appear. This improves the aggressiveness of the disc. Too soft a bond, however, causes the grain to break out prematurely so that it is not used up and the disc wears out too quickly.

If the bond is hard, the grain does not break out as easily. The grain is given longer time to cut, but must be able to break out in time otherwise it will vitrify and the abrasive power will disappear completely.

The operation

In addition to the hardness of the material to be machined, the type of machining also determines your choice of binding. Corners and burrs are sharp and pull a grain easily out of their bond. That is why it is wise to choose a hard bond for this application. This improves the performance of the disc. For flat or finer work, choose a softer binding to allow the grain to break out more easily.

Type and grit designation

The type of the example disc above contains the designation A 36 R. The A in this example stands for the grain type of alumina. The number 36 indicates the grain size. And the letter R refers to the hardness of the bond, which in this case is quite hard.

Grains may be:

• Aluminum oxide, hard tough grain
• Silicon carbide grain, very hard, but less tough
• Zirconium grain. hard and very tough
• Ceramic grain, most sharp and strong, hard and very tough

The sanding grains used today are all synthetic, natural minerals are no longer used as sanding grains.