To measure the hardness of epoxy floor paint, a set of Chinese advanced drawing pencils are used. The pencil hardness is 6B, 5B, 4B, 3B, 2B, B, HB, F, H, 1H, 2H, 3H, 4H, 5H, 6H, 7H, 8H and 9H, totally 17 kinds. From 6B to 9H, the hardness of pencil increases gradually. There are two main methods to measure the hardness of epoxy floor paint: pencil hardness tester and testing machine.
I. Measurement with Pencil Hardness Meter
1. Place the hardness tester flat on the test piece (if the test piece is smaller than the hardness tester, please put the test piece in front of the hardness tester and place the gasket below the front end of the hardness tester in order to keep the hardness tester level.
2. Cut pencil lead with blade, make the protruding part of pencil lead about 3-5mm, grind it flat with sandpaper, insert pencil into instrument, make pencil lead contact with test piece and fix and lock it. (Suggestion: pencil is hexagonal, choose a plane when fixing, rotate two planes after testing, then fix the test, rotate two planes to fix the test, one circumference can be used three times) The gasket should be removed in time.
3. Grab the center of two wheels with thumb and middle finger. Push the hardness tester back and forth about 2cm-3cm to remove the hardness tester and erase the pencil with a rubber. (Push hardness time without any pressure)
4、判别硬度，看试片有无刮痕。建议试片最少做三个位置以上，取平均值。硬度级数从软到硬分别为：6B、5B、4B、3B、2B、B、HB、F、H、2H、3H、4H、5H、6H、7H、8H、9H,共17种。例如：使用H铅笔表面无刮痕，使用2H铅笔表面也无刮痕 ，使用3H铅笔表面有刮痕，所以试验片涂装硬度级数为：2H 。
4. Discriminate the hardness and see if there are scratches on the test piece. It is suggested that the test pieces should be made at least three locations and the average value should be taken. Hardness series from soft to hard are 6B, 5B, 4B, 3B, 2B, B, HB, F, H, 2H, 3H, 4H, 5H, 6H, 7H, 8H, 9H, totally 17 kinds. For example, there are no scratches on the surface of H pencil, 2H pencil and 3H pencil, so the hardness of the test piece is 2H.
II. Testing Machine Method
A. Pencil processing. Cut the pencil rod to expose the lead core 3 mm. The pencil is perpendicular to the sandpaper and rubs in a circle on the sandpaper to make the end face flat and the edge clear and sharp.
B. Fixed specimens. Place the floor paint test piece on the test machine and fix it.
C. Adjust pencils. Starting from 6B, the pencil is placed in the pencil fixture. The pencil tip is at the intersection of the vertical line of gravity center of gravity of the test machine and the test piece of floor paint. The fixture is tightened.
D. Adjusting the balance weight. Adjust the balance weight on the left side of the floor paint tester so that the pencil tip touches the floor paint specimen, but the pressure is zero, tighten the fixing screw.
E. Place heavy objects. Place 1KG weight and loosen the fixing screw.
F. Testing. The hand wheel is shaken at constant speed, so that the floor paint specimen moves in the direction of the pen core at a speed of 0.5mm/s. Each hardness marking pencil scratches five times, and each stroke needs to be re-polished pencil.
G. Check the scraping results. If two or more coatings have not been scratched, replace a pencil with a higher hardness and repeat the steps above. If there are two or more scratches in the five scratches, the above hardness label is the hardness of the floor paint film.