Bronze Disease on Coins

Post Reply
User avatar
TerraBritannia
Posts: 542
Joined: Sat Jul 18, 2020 7:01 pm
Location: North Yorkshire
Has thanked: 920 times
Been thanked: 465 times
Contact:

A while back I found a half reasonable Roman coin, it had lost some of it's crumbly edge, but some of the detail was still fairly readable. The said coin also came with some rather nasty patches of Bronze disease too, not too much of an issue so long as you keep it in a dry enviroment, but there's moisture just about everywhere when you think about it.

I'd done some googling on Bronze Disease as you do and I'd read that a solution of sodium sesquicarbonate and distilled water might be the best option to try and neutralise the rot. Sodium Sesquicarbonate is actually quite cheap to buy and I only paid £4.99 for a 1 Kilo bag, the distilled water was more expensive. :shock: Apparently you can make your own Sodium Sesquicarbonate, although it's easy to get the mixture wrong. I played safe and got some pre-made.

There's plenty of info on the internet regarding SS, but this is the site that I bookmarked and followed the advice from.
https://www.accla.org/actaaccla/bronzed ... erapy.html

I made a solution of 95 ml distilled water and 5 grams of SS, mixed it in well and popped the Roman coin in. That was 9 days ago and today I've had a look at the coin, mixed up a fresh solution and put the coin back in. I'll update in another week's time (or there abouts).

The coin has lost it's green patina, but I knew that was a possibilty and although the bronze disease is still visible in some areas, but I don't think it's as bad as it was before. This may be a long process. :D

Before on the left, after on the right. The dark patches on the right side of the coins are actually shadows from where I was holding the coin.

Roman Coin - Solution.png
TerraBritannia [previously known as TerraEnglandia] but Andy is my real name.
https://www.youtube.com/TerraBritannia
Minelab Equinox 800
Pete E
Posts: 862
Joined: Mon Jul 20, 2020 10:05 pm
Location: North Wales
Has thanked: 1027 times
Been thanked: 608 times

Interesting post Andy...With regards using distilled water, I have often wondered about using the water recovered from a condenser tumble drier?

Given that is been condensed down from steam, surely that's a variation of the distilling process?
User avatar
figgis
Posts: 2701
Joined: Thu Jul 09, 2020 6:21 pm
Location: Norfolk (just)
Has thanked: 1267 times
Been thanked: 1478 times

Thanks for the post, Andy, and look forward to seeing any updates :thumbsup:

I had a go with SS on my statuette (see avatar) a while back but after a while the water started to turn green, which is apparently not the good thing I thought it would be so I stopped.

My ex-FLO once said that the only way to truly manage bronze disease is via a vacuum chamber where all moisture will be removed from the metal. So I'm currently experimenting with a Henry hoover, the child's tent I nicked from next door, and lots of duct tape to see if I can cobble something together. Watch out for a vid soon :lol:
User avatar
Easylife
Posts: 2244
Joined: Sun Jul 19, 2020 2:47 am
Location: Valhalla
Has thanked: 1689 times
Been thanked: 1697 times

figgis wrote:
Sun Jul 18, 2021 7:07 am
I had a go with SS on my statuette (see avatar) a while back but after a while the water started to turn green, which is apparently not the good thing I thought it would be so I stopped.

My ex-FLO once said that the only way to truly manage bronze disease is via a vacuum chamber where all moisture will be removed from the metal. So I'm currently experimenting with a Henry hoover, the child's tent I nicked from next door, and lots of duct tape to see if I can cobble something together. Watch out for a vid soon :lol:
Just stick it in the oven for a few hours (gas mark 6), then paint it with underseal and jobs a gud un! :D
User avatar
figgis
Posts: 2701
Joined: Thu Jul 09, 2020 6:21 pm
Location: Norfolk (just)
Has thanked: 1267 times
Been thanked: 1478 times

:lol:

We're all-electric here, and I was planning on sealing it with roofing bitumen, but I appreciate the advice :thumbsup: :lol:
User avatar
Easylife
Posts: 2244
Joined: Sun Jul 19, 2020 2:47 am
Location: Valhalla
Has thanked: 1689 times
Been thanked: 1697 times

figgis wrote:
Sun Jul 18, 2021 12:00 pm
I was planning on sealing it with roofing bitumen.
Ooh you don't want to be using that stuff! It will eventually crack in the sun and the rain will get in, then you'll have to do it all again! :lol:
User avatar
Saffron
Posts: 542
Joined: Mon Jul 27, 2020 7:31 pm
Has thanked: 637 times
Been thanked: 649 times

I will be interested in the results as have a couple of nice items that need treating and understood that the only long term solution was a vacum chamber.

Evan
User avatar
TerraBritannia
Posts: 542
Joined: Sat Jul 18, 2020 7:01 pm
Location: North Yorkshire
Has thanked: 920 times
Been thanked: 465 times
Contact:

I'll let you know how it progresses. :thumbsup:
TerraBritannia [previously known as TerraEnglandia] but Andy is my real name.
https://www.youtube.com/TerraBritannia
Minelab Equinox 800
User avatar
figgis
Posts: 2701
Joined: Thu Jul 09, 2020 6:21 pm
Location: Norfolk (just)
Has thanked: 1267 times
Been thanked: 1478 times

Please do, Andy :thumbsup:

As a footnote to my first post above, I have to say that the statuette seems in better condition than before treatment and there's no worsening of the bronze disease. But these things go down to microscopic level so it ain't necessarily stopped altogether.
Post Reply