What type of metal is this?

Old 07-20-14, 12:15 PM
Thread Starter
Join Date: Jul 2014
Location: USA
Posts: 4
Upvotes: 0
Received 0 Upvotes on 0 Posts
What type of metal is this?

I need help identifying this metal (see attached photos). The metal is used all over my newly-purchased property for doors, gutters, flashing, railings, etc. White chalky spots have been appearing on it recently. I've tried CLR, vinegar, backing soda, rust remover, etc. and nothing seems to be removing it. Some of those chemicals actually took the flat gray finish off the metal. I'm not sure if it's hard water stains, white rust, or something different. Please help!
Attached Images   
Old 07-20-14, 12:56 PM
chandler's Avatar
Banned. Rule And/Or Policy Violation
Join Date: Dec 2005
Location: USA
Posts: 36,607
Upvotes: 0
Received 11 Upvotes on 10 Posts
It looks to be aluminum. Steel, even galvanized will rust at the impact points where it is bent and cut. What you are seeing is "white rust". It appears on aluminum when subjected to cold and heat and moisture. Not much you can do with it. You may can etch it with a chemical and paint it. Wait on Marksr to chime in here with his paint knowledge.
Old 07-20-14, 01:00 PM
Gunguy45's Avatar
Super Moderator
Join Date: Dec 2007
Location: USA
Posts: 19,281
Received 8 Upvotes on 8 Posts
Looks like some sort of phosphate coated steel. I assume it's magnetic which indicates steel. If you can't get a definitive answer here, you might try Finishing: Anodizing, Plating, Powder Coating, & Surface Finishing They have a Forum for all sorts of questions about different metal finishes and problems.

Oops...I spent so much looking at the pics I didn't see all the things it was used for. If it's not magnetic, then very likely its aluminum.
Old 07-20-14, 02:33 PM
XSleeper's Avatar
Group Moderator
Join Date: Dec 2004
Posts: 27,305
Received 1,973 Upvotes on 1,770 Posts
Looks like steel to me. The magnet will tell for sure. The door was probably originally primed grey but looks to be losing it's paint job (nothing lasts forever without maintenance!) and the jamb and hinges just look like they used to be bare or galvanized steel that's getting rusty from having no finish on it at all... or maybe it was once primed but never got painted.

If you're near salt water that might explain some of it.
Old 07-21-14, 03:32 AM
GregH's Avatar
Super Moderator
Join Date: Jan 2001
Location: Manitoba
Posts: 9,500
Received 68 Upvotes on 62 Posts
Looks to me like galvanized.
Old 07-21-14, 04:11 AM
Forum Topic Moderator
Join Date: Mar 2005
Location: USA - N.E.Tn
Posts: 45,809
Received 873 Upvotes on 764 Posts
Let us know what the magnet does. That will determine if cleaning/buffing will bring the luster back or if you need to prime and paint. Aluminum paints well if you don't want to spend the time to clean and polish it. What coatings to use is dependent on what type of metal it is.

Thread Tools
Search this Thread
Ask a Question
Question Title:
Your question will be posted in: