How to mix zinc-rich paint correctly?

Since zinc-rich paint is usually two-component and has high zinc powder content, the viscosity is very low due to a large amount of thinner before painting, and it is easy to settle, resulting in uneven zinc powder content in the coating film, which requires zinc-rich paint Constant and effective agitation is maintained throughout the spraying process. Therefore, it is an important content to ensure the quality of zinc-rich paint to make strict regulations on the mixing container, agitator form, mixing method, and mixing time.

① Requirements for zinc-rich paint mixing tanks

In order to ensure the mixing and stirring effect of zinc-rich paint, two mixing tanks should be connected in series, A tank is used for premixing, and B tank is used to supply paint to the system. The volume of the two mixing tanks generally cannot be less than 100L. In order to ensure a better mixing effect, the amount of zinc-rich paint should be less than 2/3 of the height of the mixing tank.

Due to the high density of zinc-rich paint, it is very easy to produce hard deposits, so the main agent should be stirred evenly in the original packaging barrel with a specific three-blade mixer before pouring into the mixing tank. A single three-edged agitator should also be used in the mixing tank, but the diameter of the stirring paddle should be larger in order to achieve a good mixing effect in a mixing tank with a larger diameter.

The agitator in the mixing tank A should be located in the center of the mixing tank, the speed of the agitator is 1200~2000r/min for the shop primer, and 1400~~2400r/min for the intermediate paint and interior paint. The bottom of the tank should have a slope of 5°~10° to facilitate the flow of paint and prevent the deposition of zinc powder. In order to ensure the stirring effect, the stirring paddle should be located on the baseline of the cylinder at the bottom of the tank. There must be a valve at the bottom of the tank to adjust and control the rate of zinc-rich paint flowing into the mixing tank B. The furthest distance should be kept between the paint line from tank A to tank B and the paint suction pipe of the paint spray pump.

② Zinc-rich paint mixing steps

a. Open the bucket of zinc-rich paint main agent.

b. Use a portable stirrer to stir the zinc-rich paint main agent in the original packaging barrel for 1-2 minutes.

c. Open the curing agent packaging barrel.

d. Pour the curing agent into the main agent that has been stirred evenly.

e. Then mix and stir the main agent and curing agent for 1-2 minutes.

f. Pour the zinc-rich paint that has been mixed and stirred evenly into the mixing tank A.

g. If the demand for zinc-rich paint is large, repeat the above steps to add more barrels of zinc-rich paint.

h. Use a small amount of solvent to clean the used main agent and curing agent packaging barrels so that the remaining paint can be fully used, which can reduce waste and ensure the correct equivalence ratio of the paint.

i. Pour the solvent used for cleaning the packaging barrel into the mixing tank A.

j. Stir the mixing tank A for 2-3 minutes to fully mix the zinc-rich paint and solvent. Then open the control valve to allow the evenly stirred zinc-rich paint to flow into the mixing tank B.

k. Stir the zinc-rich paint in the mixing tank B for 2 to 3 minutes, and prepare the paint spray pump at the same time.

l. Keep stirring continuously and start painting. And keep stirring throughout the entire painting job.

m. When the zinc-rich paint in the mixing tank is about to be used up, repeat the above operations a~j, re-mix the zinc-rich paint and put it into the mixing tank B.

③ Stirring after work interval

During the painting construction, there are often short work intervals caused by equipment maintenance, workers eating and resting, and process rhythm. After resuming operation, the following points should be paid attention to.

a. Zinc-rich paint has a mixed service life requirement. If the mixed use period is exceeded, the performance of the paint will be affected, and serious gelation will occur, resulting in the scrapping of equipment and materials. Therefore, the mixed use period must be considered during work intervals. If the interval is expected to exceed the mixing period, the paint in the equipment and pipelines should be removed. The mixed service life of zinc-rich paint is related to temperature. As the temperature rises, the mixed service life will be shortened. For specific data, refer to the technical parameters of the paint supplier.

b. After a working interval of more than 10 minutes, the zinc-rich paint should be fully stirred for more than 10 minutes before painting can be carried out. If conditions permit, try to keep stirring the zinc-rich paint that has been mixed during the intermittent period of construction to prevent the zinc powder from settling.