How dangerous is moisture for powder coating?

Workers frequently face the problem of clumping and poor pseudofluidization just before application — so it is difficult to distribute the loose mass evenly over the surface of a metal product. The result is a coating with visible defects. The reason is improper storage of powder coating. And even if the powder mass is already fell into lumps, it can be fixed.

 

Moisture in powder coatings

When the air is more than 70% humid, the dry powder begins to absorb liquid quite quickly. Epoxy, polyester or epoxy-polyester coatings will absorb microscopic droplets approximately equally, their composition does not affect hygroscopicity. Powder coating materials can settle and collect moisture during a short storage time, which will affect the formation of lumps. So a vibrating table, on which these lumps can be crushed, will always come in handy. It will not hurt to do manual mixing in the received container to breake lumps. It is also acceptable to dry material in a polymerization furnace: for this, spread the mixture in an even layer and heat it for two hours at a temperature of 30℃. Dry carefully and make sure that the powder particles do not fuse.

Methods of measuring humidity

It is easy to find out the ratio of moisture to dry weight with a special device — a moisture meter. It exists in different types and forms for many purposes and industries: construction, agriculture, industry. An apparatus with a special cuvette designed for loose substances is required. It heats 20 grams of products to 40℃ using infrared rays and measures changes in weight.

You can do it without special equipment — take a small amount of powder material, weigh it accurately and place it in the curing chamber for 2-3 hours at 50℃, let it cool and weigh it again — the percentage of lost weight will show the proportion of water in the paint.

Having a reliable business partner “Lacover” who knows everything about powder paint material will allow you to adjust the painting process and fulfill orders on time. The price of products is another significant advantage of ours. Choose Lacover’s quality service and become a leader in your industry!