Shotley Bridge smallsword

Raf · 4th April 2022, 04:49 PM

Or maybe not. The copper finish is more likely the result of surface enrichment . This occurs when an alloy suffers from corrosion which etches out one element of the alloy ,in this case the zinc leaving copper on the surface Not suggesting your sword has ever been buried but aggressive chemical cleaning can have the same effect. Lavatory cleaner used to be popular. Good for cleaning very dirty brass but can leave a superficial coppery finish easily removed with steel wool and polish.

Will M · 4th April 2022, 06:16 PM

I believe Raf is onto something. In the past I've cleaned brass and it resulted in this effect. Using acids can also transfer the colour onto steel components. The sword is far too early to have a copper base before plating with nickel etc. I believe plating began in the 1840's.

urbanspaceman · 4th April 2022, 09:41 PM

If you look at the earlier 'genuine' image of the sword hilt (before I photo-shopped it) you will see the areas of copper plating predominate in the lower surfaces and the areas where little to no contact has been experienced.
As far as I am aware, but I hasten to add I am not an expert in this field, copper sulphate or maybe copper oxide, I don't know which, was mixed with mercury and applied to the brass which was then baked so the mercury evaporated leaving a copper plating behind.
This was the same process used to gild those blue and gilt blades that became so popular.
Obviously, this was a hazardous process and life expectancy was poor, which was why it was a luxurious finish.
Electroplating was not established until around 1810.
My suggestion is that it was done for time at sea, apart from the excellent look.
You will also note that the colour I used to 'plate' the image was taken directly from the existing copper finish.

urbanspaceman · 4th April 2022, 09:46 PM

The other giveaway is the copper binding on the grip: the way it looks perfect against the copper plate finish but odd against the brass.

urbanspaceman · 5th April 2022, 09:12 PM

Quote:

Originally Posted by Raf

Or maybe not. The copper finish is more likely the result of surface enrichment . This occurs when an alloy suffers from corrosion which etches out one element of the alloy ,in this case the zinc leaving copper on the surface Not suggesting your sword has ever been buried but aggressive chemical cleaning can have the same effect. Lavatory cleaner used to be popular. Good for cleaning very dirty brass but can leave a superficial coppery finish easily removed with steel wool and polish.

My theory of nautical purpose would actually account for the high copper content of the brass.
I've been thinking about this and looking at the use of 'Naval Brass' which apparently has a 70% copper content.
If the zinc is leeched out of the surface then what you say is highly probable and the reason the copper finish is restricted to untouched areas may well be its removal by wear and/or polishing of the surface.
Yes, I see what you are getting at.
Pity, I rather liked the copper finish and, as I say, it blends well with the copper binding. That, of course, may again be due to nautical purpose.
Thank-you Raf.

urbanspaceman · 5th April 2022, 09:26 PM

My studies continue:
"Naval brass", for use in seawater, contains 40% zinc but also 1% tin. The tin addition suppresses zinc leaching.
This is great, I am getting more and more acquainted with metallurgy: I love learning.

4th April 2022, 09:41 PM	#3
urbanspaceman Member Join Date: Sep 2017 Location: Tyneside. North-East England Posts: 577	copper plating If you look at the earlier 'genuine' image of the sword hilt (before I photo-shopped it) you will see the areas of copper plating predominate in the lower surfaces and the areas where little to no contact has been experienced. As far as I am aware, but I hasten to add I am not an expert in this field, copper sulphate or maybe copper oxide, I don't know which, was mixed with mercury and applied to the brass which was then baked so the mercury evaporated leaving a copper plating behind. This was the same process used to gild those blue and gilt blades that became so popular. Obviously, this was a hazardous process and life expectancy was poor, which was why it was a luxurious finish. Electroplating was not established until around 1810. My suggestion is that it was done for time at sea, apart from the excellent look. You will also note that the colour I used to 'plate' the image was taken directly from the existing copper finish.

4th April 2022, 09:46 PM	#4
urbanspaceman Member Join Date: Sep 2017 Location: Tyneside. North-East England Posts: 577	ps The other giveaway is the copper binding on the grip: the way it looks perfect against the copper plate finish but odd against the brass.

5th April 2022, 09:26 PM	#6
urbanspaceman Member Join Date: Sep 2017 Location: Tyneside. North-East England Posts: 577	Naval brass My studies continue: "Naval brass", for use in seawater, contains 40% zinc but also 1% tin. The tin addition suppresses zinc leaching. This is great, I am getting more and more acquainted with metallurgy: I love learning.

4th April 2022, 04:49 PM	#1
Raf Member Join Date: Nov 2013 Posts: 252	Or maybe not. The copper finish is more likely the result of surface enrichment . This occurs when an alloy suffers from corrosion which etches out one element of the alloy ,in this case the zinc leaving copper on the surface Not suggesting your sword has ever been buried but aggressive chemical cleaning can have the same effect. Lavatory cleaner used to be popular. Good for cleaning very dirty brass but can leave a superficial coppery finish easily removed with steel wool and polish.

4th April 2022, 06:16 PM	#2
Will M Member Join Date: Mar 2012 Location: In the wee woods north of Napanee Ontario Posts: 394	I believe Raf is onto something. In the past I've cleaned brass and it resulted in this effect. Using acids can also transfer the colour onto steel components. The sword is far too early to have a copper base before plating with nickel etc. I believe plating began in the 1840's.