Aluminum is a very characteristic metal. When it is oxidized by air, a dense layer of alumina is formed on the surface. This film has superior corrosion resistance. It's not like steel that can be corroded forever. Therefore, the paint on the aluminum alloy is only for decorative purposes. But ordinary paint is difficult to adhere to aluminum alloy. The surface of the aluminum alloy must be treated before the paint layer can be sprayed.
Það eru tvær megin leiðir til yfirborðsmeðferðar á áli:
Eitt: Til að breyta eiginleikum yfirborðs álblöndunnar er hægt að yfirborðsmeðhöndla álblönduna með fosfatlausn eða fosfatandi grunni. Eftir hvarf við álblöndu myndast álfosfíðfilm sem auðvelt er að festa málningu við. Á seinna stigi er hægt að úða málningu auðveldlega.
Two types: use special aluminum alloy special primer, such as Haijian brand epoxy zinc yellow thick coat primer, Shanghai International epoxy zinc yellow primer, etc., and then use two-component polyurethane paint.
Aluminum alloy boat coating process:
1. Construction environment: the temperature of the coating environment is 5-35 degree , the relative humidity is below 85 percent , the surface temperature of the substrate is more than 3 degree above the dew point, and the temperature and humidity should be measured near the substrate. The temperature of the substrate is higher than 40 degree , so construction is not recommended. Can not paint if the painting conditions are not met.
2. Surface treatment: First, use lye and thinner to remove dirt and other contaminants attached to the surface of aluminum alloy or stainless steel. Use power tools or sandblasting methods to remove the surface oxide layer, revealing the metal color and luster and a certain degree of roughness. The surface after treatment is not allowed to have dust, oil, moisture and other dirt. After the surface treatment meets the coating requirements, it must be Apply a primer within 4 hours.
3. Paint distribution: The above paints are all two-component paints. Weigh the components before use and mix them evenly according to the specified ratio (see the above table). They can be used after curing for half an hour. The actual construction is mixed with a mixer. . Special thinner can be added appropriately (do not add epoxy thinner to aliphatic polyurethane topcoat), the amount depends on the situation, the general dilution is 5-10 percent . Note that each paint should be prepared according to the daily dosage and used immediately to avoid waste.
4. Use manual rolling or brushing, airless spraying and other construction methods, coating interval: about 12 hours (23 degrees Celsius) after the completion of the construction of a epoxy zinc yellow thick primer primer, it will dry, and continue to scrape putty putty , After the putty is dry and polished to remove dust, you can continue to apply the intermediate paint. After about 12 hours at 23 degrees Celsius, continue to apply the aliphatic polyurethane topcoat. When the temperature is high, the coating interval can be appropriately shortened.
5. After each coating is applied, there should be no obvious sagging, pinholes, shrinkage holes, orange peel, etc. on the surface. The long construction interval between two paint applications should not exceed 15 days. Before the next paint application, check the paint film for dust, oil, etc. Re-coating should be applied to the parts of partial missing coating and insufficient film thickness.