Painting galvanized metal: why, what and how?

Reasons to paint zinc coating

You can not wait for the destruction of the zinc layer, but prevent it by painting freshly installed structures, and carry out this procedure regularly. If, at first, the galvanized roof or other metal structure was used in its pure form, there are reasons to pay attention to the risk of material destruction:

• white coating completely or partially covering the sheets, speaks of the destruction and thinning of the zinc layer due to its oxidation;
• yellowing of galvanizing is an important signal of approaching rust;says that the zinc layer is not effective enough to withstand the aggressive environment.

If you miss these bells, then after, you may need to replace the galvanized roof, and not its repair.

In addition, the galvanized roof fits poorly into modern exteriors, so painting products from such steel can be primarily of a decorative nature.

How to paint galvanized metal?

Steel sheets, actively used in everyday life and during construction, tend to be hot-dip galvanized in the enterprise. There are also galvanic, gas-thermal, thermal diffusion and cold galvanizing. All of them perform approximately the same task - they protect the metal from corrosion by applying zinc. But if the first four methods are available only in production conditions, then cold galvanizing can be done by hand.

1. Painting with special polymer - this is the technology of cold galvanizing. That is, in fact, you will apply the zinc layer anew or additionally, depending on the time of operation of the roof. The composition is called zinc-containing paint and is freely sold in construction stores. It contains 89-93% zinc, and the amount of protection depends on its amount. The color palette is quite diverse to talk about the decorativeness of this decoration.
2. If there is no possibility or desire to use zinc-containing paint, powder formulations can be used. They are sold in finished form, and when heated, they polymerize and form a strong wear-resistant protective layer.
3. Paints galvanized and polyester, plastisol, aluminum waterproof compositions, although their protection is an order of magnitude lower than the above described means.
   

   Note! Do not use traditional alkyd and oil paints for galvanized metal. They are not only incapable of resisting an aggressive external environment, but also, reacting with zinc, destroy existing protection.

In any case, it should be remembered that the zinc layer reduces adhesion, and steel has the ability to expand greatly when heated. Whichever paint you choose, it should bond well even with a smooth surface and be very elastic.

Self-leveling of the roof: Step-by-step instructions for applying the enamel

Using zinc-containing primer enamels is not more difficult than conventional types of paints, so for sure you will be able to treat it with zinc coating the first time. The technology of cold galvanizing includes several steps:

1. Surface preparation: cleaning of debris and dust, removal of the old polymer layer, if it was. Try not to damage the remaining galvanizing!
2. Metal sheets should be washed with detergent or pressurized water to remove tiny particles and fat deposits.
3. A completely dry and clean metal is applied with the first layer of zinc-filled paint. It is important to apply it thinly, but very evenly. Wait until it dries completely.
4. Repeat step 3 two more times for perfect coverage without flaws and even color.

There is nothing difficult in the process of painting galvanized, and it's realistic to do it yourself. The main thing is not to rush and apply all possible accuracy at work.