My next project is an 'engineer's' set of Chess pieces using various bit of workshop materials. The 'white peices are resonably easy as they are being made mostly of brass (not white!) but Blcak is proving a bit problematic.

Is Carr's blacking liquid a surface treatment, rather than a covering, and does it produce a similar shade to the similar solutions for steel. I once blacked an engine flywheel using a hot mixture of very agresive alkali that I don't think I would be able to buy nowadays.

Tony

Have you considered using Carbon Fibre, as a modern material ?

MichaelG.

Corian. Obtainable in a wide range of colours blacks included. Kitchen fitters have offcuts. You might need to glue bits together as the standard thickness is about 12mm. You can also get pen blanks made of it. Lovely to machine.

Black Delrin is another alternative.

Emgee

Black Acetal was also my first thought but very light weight compared with brass if that bothers you? You could maybe add a weight into the bottom of the pieces?

Are the black pieces also to be made from brass?

Never used the Carr products, but it appears to be a chemical conversion treatment. The one for steel is most likely regular selenium-based cold blue which work OK but won't be nearly as wear resistant or decorative as a caustic black treatment.
A proper caustic black bath can be made from 3 parts sodium hydroxide and 1 part potassium or sodium nitrate. There should be a thread or two on this somewhere on this forum.

There are several formulations that will produce a brown to black patina on copper alloys, here are a few:

https://davidmbowman.com/patinas/formulas.htm
https://www.sciencecompany.com/Patina-Formulas-for-Brass-Bronze-and-Copper.aspx

Aluminum can be anodized and dyed into almost any color.

Blueing can also be done with heat and oil

Edited By Paul Lousick on 13/08/2023 11:13:26

I've used both the Carrs and Birchwood Casey brass blacking solutions and despite every care and degreasing in a variety of ways have only ever got a dissapointing deep brown, ok from a distance but wouldn't call it a proper black. The Birchwood Casey gun blacking (or blueing I think they call it) does work very well as does a steel blacking kit I bought from Frosts, careful degreasing seems to be the key to a lasting finish. I heated and oil blacked parts of my Simplex and they are still ok 40 years on, again to get an even finish careful degreasing is key.

If you used delrin/acetal you could glue the blank onto a steel mandrel then machine your piece and part off so you then have a heavier playing piece.

make from copper then oxidise the surface. How, no idea, need a chemist! According to this it can be done by heating in air to above 300C, might be worth trying on some bits of scrap.

You need cupric oxide, which is black, not cuprous, which is red

Edited By duncan webster on 13/08/2023 14:24:24

Hammerite Kurust Rust Converter or it's equivalent. This is a surface treatments for steel based on Tannic acid, so leaves the base metal a deep navy blue.

Other maker's equivalent preparations give much the same results. Jenolite make one, also Vactan, and Aquasteel.

Loctite also make one but it's expensive though a little goes a long way. I've recently used one called Neutrarust 661 which seems to work. I thought the resulting colour was more dark brown than blue or blue-black, but the part (a wheel rim) was pretty rusty!

Getting an even coating is going to be about cleanliness - try caustic soda rinse first. Maybe an uneven coating can add to the character of the piece.

Do do a show and tell afterwards, please!

The density of brass is around 8.5 and that of Corian is about 1.7, so it would feel very light compared to brass. SS is around 7.5 to 8.

Black paint ?

Just asking !

Make both sets of ali and load for weight ! Then anodise in 2 colours ? Noel.

Make them from steel and then apply Abbey Blue Gel as used for gun barrels. A couple of applications should give a nice dark blue colour. Fix the colour by wiping with oil or waxing.

Russell

You could go Victorian and have red instead of black. Then make the red pieces from phosphor-bronze and the white from alli.

you can get a patina solution from jewelry suplies sales.

Patina Oxidising Solution 250ml UN2922

this will give a dark finnish to silver, copper and bronze.not expensive but needs handling with care.

David

I made a chess set using nuts and bolts. The black pieces were treated with brick cleaner (hydrochloric acid) to remove the bright zinc plating and then blacked by heating and dunking in oil.

Anthony, your fastenings chess set is utterly charming

Rod