70's Copper door pull Restoration -Where to start?

[BlackRockNovice]

Hi all. Been saved by WWF many times but never had the need to post.
I have identical door pulls on the interior and exterior of a 1970's front door - well I assume they used to be identical :(
The finish on the exterior is extremely weathered. The underlying metal appears to be copper.

I have no idea if resto of this knob is possible, but it would be great to see it looking like the interior one again.
Any advice greatly appreciated.:)

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[Chief Tiff]

Welcome to the forum!

I’d hazard a guess that it is a brass of some sort. There appears to be a very heavy layer of lacquer on the inside knob, which if was also applied to the outside knob would account for its good condition. Is the bezel removable from the knob?

I would suggest first removing the lacquer by soaking the knob in cellulose paint thinners. The knob can be cleaned using scotchbrite, ideally as a wheel on a grinder. The bezel will clean up using a fibreglass “pencil” like this one. (https://au.rs-online.com/web/p/abrasive-pencils/1835226/) Once cleaned up dip it in lacquer again, many many times to replace that thick layer.

[rwbuild]

Its a form of polished anodising popular of that period, the internal dress rim will have a very small notch in the edge that touches the door, probably on the bottom side where you wouldn't see it normally, just insert a small screw driver and prize off. This will allow the dress rim to be either removed or enough room to access the mounting screws for the keeper plate that holds the whole mechanism together.
Failing a small notch there maybe 2 or 3 small indents that snap over the keeper plate and they are a bit of a pain to get off without marking the door. A trick for this one is to drill about a 2mm or 3mm hole in the bottom side on the rim BUT 3mm back from the face of the door, this allows you to use the shank of a drill bit to be inserted in the hole and then levering the dress rim off.
Hope this helps

[russ57]

Check with a magnet. Could be plated steel.
The little patch on the inside knob looks like it could be bare steel.
Also the two tone dress ring suggests plating.

[BlackRockNovice]

Check with a magnet. Could be plated steel.
The little patch on the inside knob looks like it could be bare steel.
Also the two tone dress ring suggests plating.

Thanks for the tip. Not magnetic and definite pink colour so more likely a brass, but good to rule out steel.

[BlackRockNovice]

Thanks for the tips, sounds like a good place to start.

[jack620]

That worn patch in the middle of the knob really doesn’t look like brass. If it’s not magnetic I’m also thinking anodised aluminium.

[62woollybugger]

The green verdigris means it's definitely a copper alloy, brass or possibly bronze. You could try paint stripper to remove any remaining lacquer before polishing with very fine wet & dry, then a metal polish. After polishing, give it a good clean with solvent, then spray with a clear coat.

[jack620]

The green verdigris means it's definitely a copper alloy, brass or possibly bronze.

Even this worn bit? I’m not seeing any green tint there. What’s the base metal?

[62woollybugger]

Maybe the last patch of lacquer that hasn't worn off. He's got nothing to lose by polishing it, if it's really important to keep it, he can always get it re-plated, if it turns out to be plated.

[BlackRockNovice]

Thanks for the tips and discussion. Curiosity got the better of me so I pooped the knob off and started poking around with a bit of 000 steel wool and before you know it.....
The corrosion was pretty extensive so there is a good bit of pitting. At a guess it looks like thin copper plated over aluminium (?). The lacquer had given it a gold/bronze type finish (see original pics)
Any thoughts on next steps? I could replate it with copper if all it took was a coat of lacquer to bring it back to the old look. As it is, it looks better than it was but is obviously not a match for the interior knob now i have stripped it back.
Thanks :)

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[Chief Tiff]

If the knob is a zinc/aluminium alloy then it would have been electroplated with brass; the pink copper you have left now is a heavy primer coating used between the zinc alloy and the brass alloy. You can quite easily restore the copper plating using a homemade electroplating set up, do it for long enough and you can build up a really thick layer to hide those pits. Then to restore the brass colour you could take it to a commercial plater (probably a bit exy for a knob though) or use an old blacksmith’s method of depositing brass using gentle heat and a brass wire brush. There are a few videos on you tube showing this method.