Casting Aluminium in back garden. Now looking to explore/discuss all aluminium finishes.

Casting | | |

A few years ago, through my A level DT project, I designed a piece of outdoor furniture (table/bench set). Origionally made in all wood, I'm now about to start sand casting the major structural components in aluminium.

I would like to discuss with those more experianced than I, the subject of finishing Aluminium.

The techniques I am aware of so far are;

Copper plating,
Copper plating then patinating to verdisgris,
Powder Coating,
and Anodizing.

The piece is intended for outdoor use. To be used in both conservative and artistic settings.

I am interested in all the other Aluminium finishing techniques you can name, as a basis for further research, as well as your comments on them. As well as any general experiances any of you have had, in trying to make the most of your aluminum castings.

Please comment on any and all techniques, however unusual.

Whilst im happy to do the research myself, I find these settings of information sharing more rewarding and thank in advance anyone who would like to contribute.

On more specific points of aluminium finishing,

-can anyone comment on the legalities of selling a product with real verdisgris (as im aware it's an irritant)

-what is the best looking and most durable way of colouring aluminium black.



ScottTheSculptor's picture

Cast aluminum

My backyard aluminum castings never attain the quality
necessary for polisihing.

Aluminum gets lots of bubbles, even when degassed.

If I use new silica aluminum casting ingots it's minimized.

Cast aluminum is weak. even weaker than wood in small cross section. Consider it annealed 5000 series. I cut it with hand saws and shape it with wordworking tools. blades get gummy

but you need a even surface prep to get a consistent darkness. beadblasting.

The "new" anodizing is just capturing dyes in the oxide suface as it grows. Rit dye, a plastic tub and a battery is all you need. Same setup and some copper sulfate to electroplate copper - I haven't tried it on anything large.

("old" anodizing relied on the oxide thickeness for the color - a lot more difficult to control)

visitor's picture

Hey Al, New to this site so

Hey Al,

New to this site so I just saw your post.
I too am casting aluminum, mostly for cost issues against Bronze.
I have no problems polishing my pieces.
Sculpt Nuveau has 2 finishes they sell for aluminum. One is black the other is caled Slate Black but gives a rich dark brown patina. However, with the slate black I am having an issue with a lingering sulfur smell. If you seal it afterwards the smell is contained but some more experimentation is in the works.

A friend of mine told me about a patina blacksmiths sometimes use on iron to get some rich greens and he tried it on aluminum with some good results.

I just tried this last night and got the richest of honey tones. Really beautiful!

50% bri wax (clear) (get at woodworker suppliers,
50% linseed oil
cap full of japan dryer to gel it up

Melt bri wax in double boiler setup,
add linseed oil, add japan dryer (1capfull per lb of other ingredients)

Heat aluminum evenly with roofing torch setup. Enough to let Bri mixture flow over entire piece. Start to torch already applied wax. Heat until your start seeing a greenish blonde tint start to form.
You can now experiment with heat, I was using heat on for ablout 10 seconds in an area, then letting it cool a bit. When it is cooling you will start seeing it get darker. Just gauge the level of darking against the time of the torch and go over the rest of your piece to your liking. You can burn this finish by overheating so proceed slowly after the greenish tint.

You can email me at for some pics or to talk more.

I would appreciate you emailing me any other finishes you find.