Water sandpaper is a consumable material commonly used in electroplating pretreatment. Its quality is directly related to the effect and benefit of pretreatment. Therefore, the quality of water sandpaper used should meet a certain standard before it can be used. Some substandard water sandpaper, the abrasive will fall off or the backing paper will be broken when it sees water, so it cannot be used at all. For this reason, when choosing water sandpaper, it is necessary to test its quality. Usually, the tests that need to be done include the following items.
(1) Water resistance test
After immersing the water sandpaper in tap water at a temperature of 60°C for 1 hour, rub the surface of the sandpaper with your fingers to observe whether the sand grains fall off, and it is qualified if there is no fall off.
(2) Tensile strength test
The tensile strength test needs to be carried out on a tensile machine. Cut the sandpaper into strips with a width of 25mm and a length of about 150mm. Stretch at a speed of 35cm/min until it breaks, and read the reading of the tensile machine, which is the tensile strength. You can choose the texture of sandpaper paper to test in two different directions, and generally the strength along the grain direction will be higher. Different paper and different types of sandpaper have different requirements for tensile strength. If it is along the grain, it must be at least 6.5kg. If there is no tensile machine, you can also use a spring balance and clips to do a manual pull test, and you can measure roughly of tensile strength.
(3) Softness test After the sandpaper that has passed the water resistance test is kept in the air at 2°C for 1 hour, it is bent 180° on a round rod with a diameter of 15-60mm, and the cracking on the surface is observed. If the sand is fine, use a rod with a smaller diameter, and if the sand is coarse, use a rod with a larger diameter. The width of the cracked opening is not more than 1.5 times the thickness of the sandpaper.
