The choice of sanding belts is very wide. Depending on the need, different widths, grain, composition and elasticity of belts can be selected. To achieve the optimal result and extend the life of the belt, several aspects need to be taken into account, such as the correct selection of belt, proper use, recommendations for storing belts.
Selection of sanding belt
Before choosing a belt, the most important thing is to find out what kind of machine it will be placed in, what kind of wood will be sanded and what the result is desired. The machine tools used define the width of the belts that can be used in them. Optimizing the work is aimed at achieving the desired result, performing as few operations as possible. The most important task for this is to properly select the grain and material of the belt. The grain used today are of synthetic origin and thus have better properties than previously used natural minerals. The coarser grains are suitable for initial rough sanding, but fine grains are required to achieve a smooth surface. Since the grain is selected not only in regards to its size, density of filling, but also in hardness, fragility, therefore, each case of sanding becomes individual and it is necessary to evaluate all these parameters separately in order to achieve the desired result. The size breakdown of the grain shall comply with the FEPA standard. The higher the number according to FEPA, the finer the grain.
| FEPA | P12 | P16 | P20 | P24 | P30 | P36 | P40 | P50 | P60 | P80 | P100 | P120 | P150 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Grain size | 1400-2000 | 1180-1700 | 1000-1400 | 850-1180 | 600-850 | 425-600 | 355-500 | 250-355 | 212-300 | 180-250 | 125-180 | 106-150 | 90-125 |
| FEPA | P180 | P220 | P240 | P280 | P320 | P400 | P500 | P600 | P800 | P1000 | P1200 | P1500 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Grain size | 63-106 | 53-90 | 45-75 | 34-82 | 28-70 | 22-59 | 16-49 | 14-44 | 12-40 | 8-30 | 5-25 | 4-20 |
When choosing a sanding belt, it is important to pay attention not only to grain size but also to grain fill density (closed grain, open grain or ultra-open grain), binder (resin on resin, resin on glue or glue on glue), method of gluing the belt.
No less important is the base of the belt – paper or material. The base of the belt is not only the base of the work surface (abrasive), but also the power transfer of the machine on the sanding surface. The larger the grain on the belt, the more powerful the machine is needed, which means that a stronger belt base is needed. When sanding profiled parts, it is very important that the tape is flexible, then it moves perfectly on the surface of the part being sanded. The fabric backing belts are longer and more stable than the paper backing. Depending on the structure, the fabric backing can be hard, and vice versa, very elastic. The strength and flexibility of the paper backing belt is directly dependent on the density of the paper.
| Paper backing thickness marking | Density |
|---|---|
| A | 70 g/m2 |
| B | 90 g/m2 |
| C | 125 g/m2 flexible and sturdy |
| D | 180 g/m2 |
| E | 250 g/m2 sturdy |
| F | 300 g/m2 very sturdy |
| G | 450 g/m2 |
| Marking of fabric backing thickness | Purpose |
|---|---|
| H | very durable, waterproof |
| X | durable |
| J | flexible |
| F | very flexible |
| W | durable, waterproof |
Many factors need to be considered in order to achieve the desired result by sanding and increasing the cost-effectiveness of the processes. This is not only the right choice of belt, but also the proper alignment of the sanding machine, the speed of the tape rotation and the feed speed.
Effective sanding process
For the most efficient grinding process, it is first necessary to correctly adjust the machine. The correct choice of sanding shaft pressure depends on: the power of the machine, the width of the contact surface between the belt and the working surface and the thickness of the base of the belt (including the shaft itself). The hardness of the sanding shaft is chosen depending on the grain size of the belt, the size and hardness of the sanding part.
A sanding belt should be put on before starting the sanding process. This requires that the machine is switched off, properly adjusted, and that the dust extraction system is working. You should then check that the correct size of belt is selected or applied in the correct direction. After making sure that the tape is correct, the tension and clamping of the tape should be checked. It is prohibited to work in the presence of inflammable objects in the vicinity, it is necessary to divert sparks from people and objects. After starting work, wait until the belt reaches the required working speed. Recommended belt rotation speeds depend on abrasive material:
| Sanded surface | Speed |
|---|---|
| Heat sensitive materials, plastics | 5-15 m/s |
| Carbides | 8-15 m/s |
| Titanium and similar alloys | 8-15 m/s |
| Glass, porcelain and spacious metals | 8-15 m/s |
| Heat resistant plastics | 20-30 m/s |
| Wood | 15-30 m/s |
| Stainless metal, high speed metal and tool steel | 20-30 m/s |
| Cast iron | 30-40 m/s |
| Carbon steel | 30-40 m/s |
| Bronze, copper, titanium | 25-35 m/s |
| Aluminum and other light metals | 20-35 m/s |
| Varnish | 10-15 m/s |
Excessive pressure during operation may overheat the belt. It is not recommended to wear loose clothing that could be covered by a sanding belt.
Storage of belts
It is advisable to store the belts in their original packaging until they are used. Before use, the belts should be as close to the working weather conditions as possible (preferably near the grinder) for at least 48 hours. Once belts have been removed from the boxes, they should be hung vertically at a sufficient distance from the abrasive surfaces. The belts should not be hung close to the wild wall due to possible condensation, nor is it advisable to keep them close to the heating unit. The temperature should be between 15 and 25 degrees Celsius and the humidity 45-75 percent to prevent the belts from deforming. Under no circumstances should they be exposed to direct sunlight. Care should also be taken to lift the boxes with belts off the floor to prevent changes in humidity and temperature.