How to dull Galvanized Steel Structures for San Diego Forest and Environment Authority

April 23, 2009

Iam looking for recipe of Dulling on Galvanized Steel Structures (Hot dipped Galvanized High Tension Transimission Towers) acceptable to San Diego Forest & Environment Authority - USA.

I experimented with 5% HNO3 ( Nitic Acid ) & got dulling effect of lower blackish gray shade but more darker shade is not achieved even after dipping the sample for 7 minutes.

Can expert from the similar field suggest how to achieve dulling without scrificing galvanized coating of minimum 100 Microns.

Chandrashekhar Chandorkar, QA manager
transmission tower mfg - Nashik, Maharashtra, India

May 19, 2009

you could explain it to them the lustre in galvanizing will fade away soon and the material will have dull finish,

however if you still wish to achieve dull coating you can opt for one of the following,

1) avoid adding aluminium or tin in zinc kettle

2) a dip in pickling rinse will give a dull finish immediately what you are looking but it's not recommended.

RegardsDUBAI

S.R.Ameen
- DUBAI, U.A.E.