Where the
world gathers for metal finishing
Q&As since 1989


-----

White Rust on Sheeting

 

I wonder if you could give some advise for my problem. I am a Civil Engineer, building a large factory. We are using a product called Ferrotherm (this is an IBR 0,6mm roof sheet with sisalation stuck to the underside, eliminating the tedious wires and rolls of sisalation usually used.) This sheeting has been on site for some time now and even though it has been covered with plastic, water and moisture has gotten between a lot of the sheets and "White Rust" has developed.

IS THERE ANYWAY OF TREATING THE SHEET TO ELIMINATE THE RUST? IF THIS PRODUCT AVAILABLE IN SOUTH AFRICA?

Thank you for your assistance.

Looking forward to your speedy response.

Grant Heiberg
- Swaziland, South Africa

---

A yellow chromate will give a fair measure of protection from white rust. (salt spray specification is 168 Hour.) A clear chrome a will give some protection. C yellow chromate followed by a zinc chromate paint/primer [affil links] will last 30 years if applied properly.

Don Baudrand
Consultant - Poulsbo, Washington
(Don is co-author of "Plating on Plastics" [on Amazon or AbeBooks affil links]
           and "Plating ABS Plastics" [on Amazon or eBay or AbeBooks affil links])
 

---

Would you not be interested in putting plastic ibr roof sheeting instead of steel, no need to coat etc.

Regards,

Tony Marshall
- Pretoria, South Africa