Summary for spangled galvanize finish Discussion
Need spangled galvanize finish is the thread’s focus: Matt Field asked how to get galvanized steel to keep its spangle but appear dull gray rather than bright. Dr. Thomas H. Cook replied that, in his experience, the simplest route is often to wait a few months for the coating to naturally dull down. He added that older galvanizers sometimes used a caustic tank to dull galvanizing, but when he tried that in the lab he had problems with white rust. Cook also noted that chemicals once existed for this purpose, but said that approach does not seem popular anymore. The discussion therefore points to natural weathering as the safest commonly mentioned option, while warning that aggressive chemical dulling can create corrosion issues.
Q. I am trying to get a dull grey type of look from galvanized steel. I have seen it around, the galvanized metal still has the spangle in it but is a very dull look. Can anyone help me out with this?
Matt Field
Sheet Metal and Steel Fabrication – Sparks, Nevada, US
August 16, 2012
A. Sir:
If you wait a few months the product will likely dull down. In the old days some galvanizers would put the product into the caustic tank to dull the galvanizing. I tried this in lab and had some problems with white rust. In those days there were chemicals available to do the job. I do not think this is popular anymore.
Regards,
Dr. Thomas H. Cook
Galvanizing Consultant – Hot Springs, South Dakota, USA