Sunday Chemistry Class

Brass wire test L-R Oxy powder, Vinegar  Raw brass

I am, as my Dad constantly reminds me, a bit strange. Therefore experimenting with various household chemicals to see what patinates raw brass should come as no surprise. I regularly use liver of sulphur to patinate sterling silver. Its a quick, inexpensive product available from many jewellery making suppliers that creates a blackened effect on the surface of the metal, which can then be buffed and polished to leave only the recessed or engraved areas black. But this doesn’t work on brass. With the rising costs of precious metals I started looking to the other ‘base’ metals as alternatives.

Copper can turn the skin green so I discounted that, but brass is having something of a revival. Companies like Vintaj and Trinity Brass Co have been producing solid brass stampings and findings, many using vintage presses, for use as jewellery components. Their pieces come ready finished, with a nice antiqued patina, whereas raw brass looks, well, brassy. It needs a bit of ‘knocking back’.

First I tried heating it. This did indeed dull the shiny surface, even creating some lovely colours, bit the effect wasn’t very strong or evenly distributed. So I tried good old liver of sulphur. It might smell like rotten eggs, but its works a treat on silver, but alas, not on brass. Again, it did something, but created more of a reddish tinge.

So I got to thinking about other chemicals that affect brass, and what I already had in various products around the house. Someone suggested anything acidic might work, so I put a generous glug of malt vinegar in some hot water with a piece of brass wire. As brass door handles tarnish in the air, I also tried a scoop of oxygenating stain remover, the type you add to the washing powder. Again added to about 150ml of hot water with a bit of wire. Nothing happened instantly with either, unlike with silver in liver of sulphur, so I left them overnight. And in the morning? The vinegar wasn’t as even or as deep an effect as I was looking for, but it left an antiqued, weathered patina, that would be more suited to finishing a piece where you wanted a more subtle vintage look. But oxygenating stain removal powder works beautifully! It created a black effect on the surface, that is even but does come off easily, so does need either lacquering or a finishing wax like Renaissance Wax.

I decided to have another go, this time with a concentrated paste of about a teaspoon of hot water with a scoop of powder. This worked much quicker, reckon I got a good depth of patina after an hour or so. If you are using metal stamping and want to keep a black effect in the indented letters but have a shinier surface, this is the way to go. Just polish it up afterwards with Brasso.

Result after 1hr in Oxy Powder paste
After a quick polish with Brasso

Who needs to buy chemicals when they are already in your cupboards, eh?!

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