How to darken aluminum

A. Hi M.
Goran has already offered a highly detailed solution that sounded like a bullseye to me. But please return the favor by letting us know how it works.

Luck & Regards,

Sure thing, Ted! I wasn't sure if that method would work on an alloy like that of Wilton. I'll try olive oil and get back to this thread.

Hi Ted,
So I tried Goran's recipe of olive oil on the aluminum and it certainly worked to change the patina -- but it turned it from gray to a shiny brass; not exactly what I was looking for. Reading Goran's thread more carefully, this makes total sense in the context of creating a brass/bronze patina. The question of how to only darken the aluminum patina however still stands. Also do so, if possible, without the use potentially harmful chemical agents, as the Wilton pieces are meant for food.

I recently started collecting vintage Wilton Armetale dinnerware. Their website says the metal they use in their products is an 'aluminum-based alloy' and to never put it in the dishwasher as that will darken the patina significantly. I however want this darker, more pewter-like patina on my pieces. So far, I've run them on the pots/pans cycle of my washer, using cascade liquid dishwashing soap, but the patina isn't as consistently dark as I've seen elsewhere. Since the pieces aren't exactly aluminum, but some unknown (trade-secret) alloy, what would work best for this; keeping in mind that they still need to be food safe when I'm done?
Thanks!

A. There is chapter on chemical coloring of aluminum (no need for anodizing) in my small download free booklet on metals coloring and plating: https://www.finishing.com/library/budija/budija.pdf

Hope it helps and good luck!

Wow! Thank you so much for this, Goran. This is the most promising lead so far for me; I’ll be sure to take a look.

A. Aluminum doesn't rust and can't be made to rust, Walter. A rust-colored paint or tint may be your best option. I have seen in the home decorating magazines that the paint manufacturers are offering all sorts of rust colored and patina colored paints.

A. Dear Marc!

This process can be used on any metal (if that metal can be heated to 400 °C). According to old books olive oil is best for aluminum. White of an egg is usable, too. With linseed oil I have coloured a piece of aluminum to bronze brown (bad smelling and tedious!). You can use 20% shellac solution instead of oil.

Good luck!

A. Hi Dan. When we don't even know what kind of metal we have, people can't tell us what chemical/acid/alkali we can react it with to get a look (it's a bit like finding a bag of some kind of white powder in the cupboard and trying to figure out what you should add to the mystery powder to make a cake). Instead, I'd suggest priming it with a primer made for aluminum and galvanized metal, then applying a metal solution, and a patina solution for that metal.

Luck & Regards,

A. Hi Kenneth. It's hard to fully understand this component from the description, but if that cap is now a permanent part of the rifle, I certainly wouldn't heat a whole antique rifle. Pick a brush-on patina of some sort; if adhesion seems problematical, prime it with a primer for aluminum and galvanized metal first [on eBay or Amazon] .

Luck & Regards,