10F, Building B, Erqi Center, Erqi District,
Zhengzhou City, Henan Province, China

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User Guide to Prepainted Steel

Here is a user guide to pre-painted steel products. Please keep reading for more details.

Storage & Transportation

When lifting the steel sheets with a crane, use a nylon belt and beams instead of a steel wire rope. If the steel sheets exceed 10 feet in length, 2 or more people are required to lift one side to avoid sagging. Besides, keep the pre-painted steel sheets dry during transportation and installation. When handling and installing steel sheets, wear dry and clean gloves. Do not drag steel sheets on rough surfaces. Moreover, the steel sheets should be placed on the skid, inclined at a certain angle, and covered with a rain cloth to avoid getting damp. If the sheets are wet, wipe them with clean gauze immediately, and place them in a ventilated place until completely dry.

At Wanzhi Steel, we often adopt seaworthy packing. The coils are sheets are packaged with waterproof kraft paper, plastic film inside, and galvanized sheets outside. Then they are tied with steel strips. Besides, coils are fixed with wooden pallets, and sheets are packaged in bundles. The bundles are separated by wood billets. If you have special requirements, please talk with us.

Besides, Wanzhi Steel offers full after-sales service. If you have any questions when you receive the goods, please feel free to contact us. We will get back to you in 12 hours and will offer you a solution ASAP.

Wanzhi Coil Packaging

Wanzhi Coil Packaging

Packaging of GI Corrugated Sheets

Packaging of GI Sheets

With Organic Film

Some color-coated sheets are covered with a transparent organic film. The organic film can protect the coating from scratches during storage and transportation. While it needs to be peeled off immediately after installation. Sunlight will enhance the adhesion between the organic film and the surface coating. Therefore, the color-coated sheets need to be covered to avoid direct sunlight.


Do not leave metal filings, drilling chips, and other metal objects such as rivets and fasteners on the surface of the color-coated sheet during installation because the metal residues will cause rust spots if they are eroded. These residues should be swept immediately, or at the end of each day’s work to avoid damaging the paint film.


You can use professional cutting tools, such as straight shears, arc shears, manual shears, etc. But do not damage the coating or plating of the steel sheet when cutting. Besides, the cutting edge must be kept sharp to reduce burrs. Do not cut on other painted steel surfaces.

Slitting PPGI Coil into Strip

Slitting Process

PPGI Plain Sheet

Cutting into PPGI Plain Sheet


When choosing fasteners, pay more attention to longevity and aesthetics. Fastener materials include carbon steel, 300 series, 400 series stainless steel, and aluminum. Cold galvanized or pickaxed fasteners are not recommended to use because of their thin coating. During installation, the fasteners should be properly tightened to avoid tilting and over-tightening. Improper fastening position and loose screws will cause water leakage, which will cause corrosion at the fasteners. Over-tightening will cause deformation of the color-coated sheets, resulting in water accumulation and accelerated corrosion.

Use in Sandwich Panel

Due to the electrochemical reaction, lead and copper will accelerate the corrosion of galvalume steel. Lead cannot be used with galvanized steel sheets, and copper cannot be used with both GL and GI sheets. The recommended materials for the sandwich panel are GL sheets, PPGL sheets, and aluminum sheets.


Butyl elastomers, polyurethanes, acrylics, and silicones can be used as sealants, and neutral silicone is recommended. The sealant should be fully coated in the junction since the sealant coated on the surface will deteriorate due to UV.

Eaves edges

Affected by rainwater and condensation, the edge of the dripping eaves severely corroded. Initially, microscopic air bubbles appeared on the cut edge. Over time, “red rust” occurs near the cut edge. It is not recommended to slit or trim the color coated sheets. And the edges should be fully protected by GL coating and zinc coating.

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