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Coil handling and finish protection · Lesson 2 of 4

Coil handling and finish protection: materials, standards and design constraints

What painted, galvanized and Galvalume stock each fear, why condensation and sealed wraps cause stain, the stock-age and film limits published by different makers, and how a colour is identified.

You will be able to: Identify what damages each finish AFS handles, set the storage conditions that prevent it, and apply the supplier's age and film limits for the material in hand.

12 min · 12 slides · 11 questions

All lessons in this module
Slide 1 of 12

What each finish fears

Each finish has its own enemies:

  • Painted: scratches, film baked on, swarf rust
  • Galvanized: wet storage stain (white rust), fretting
  • Galvalume: grey-to-black stain, fingerprints, contact with incompatible materials
  • Zinc and copper: skin oils stain them

Sources

Videos for this lesson

What this video shows: Sheffield Metals with a film maker on what strippable film is, its types and what happens when it is left on too long; it closes with a segment about the film maker. Follow your own film supplier's time limit.

Video: Why is Protective Film Used for Metal Roofing? by The Metal Roofing Channel, on YouTube. Chosen from the video's published description.

Glossary

Wet storage stain
Corrosion product that forms where tightly packed metallic-coated surfaces stay wet without free air circulation: white on zinc, grey to black on Galvalume.
Passivation
A mill chemical treatment that reduces, but does not prevent, storage stain.
Fretting
Black marks caused by load and small repeated movement in transit; mainly cosmetic.
Dew point
The temperature below which moisture in the air condenses on a surface.
FIFO
First in, first out: the oldest stock is used first.