I'm no metallurgist, but...

[fairlie63]

In 1930 when corps and regimental badges were reintroduced to the Australian Military Forces the specifications for the badge metals were brass, 'dipped bright' and scratch brushed on both sides. The bright dipping was a peroxiding process that stopped the metal tarnishing after its initial brightening.

On 11 December 1931 the Military Board directed that in relation to badges the term 'gilding metal' was discontinued and the term 'brass' substituted.

Keith

[Neibelungen]

Gilding metal as pointed out was a very high copper low zinc brass (usually 95/5) and has a colour that was more reddish yellow than brass.
One of it's main features was that it was softer than common brass (65-70/35-30) and flowed and moved better in an annealed state than normal brass.
Normal brass has a lower limit to it's 'flow' and would crack or split when the stress of die stamping passed a threshold point depending on the annealed state of the metal.
It's secondary quality was that because of the higher copper content it meant that gilding (either fire gilding with mercury/gold or gold electroplating) would adhere better to it

One of the main reasons for a move over to gilding metal was the slow change towards hydraulic stampings from the 1870's onwards, which has a different quality of pressure and metal 'flow' in a strike compared to striking in a drop hammer. Broadly speaking you tend to find the hydraulic process and dies work best on a shallower strike, but have a more uniform thickness, while a drop hammer will allow a bolder or deeper strike but make the metal more variable in thickness. The die cutting also reflected this as the former 'squeezes' the metal more and the later 'moves' the metal more.
One of the benefits of a uniform thickness was that piercing or trimming dies could be more effective and less prone to breakage (allowing the replacement of hand piercing) as the clearance between piercing punch and the die is related to the thickness and hardness of the metal. (too much gap and you leave a longer burr, too little and the stress on the die increases (deflection) and the metal cut becomes ragged or breaks uncleanly

The different colours you find on 'brass' badges often relates to cleaning, annealing or pickling processes involved in the manufacture as well as the metal composition.
Heat and acid pickles cause local surface depletion of zinc and or copper from the metal, giving it a more yellow or red appearance too. Zinc will dissolve or evaporate at a different rate to the copper at different heating ranges (from soldering lugs or annealing) or copper can brought to the surface in preference. (hence while the metal can be a uniform 95/5 mix, in local spots or the surface it can vary from 80/20 to 99/1).

(Standards for gilding metal composition were not set down in regulations till around 1904 and manufacturers could have a % or two variation as to what they defined as gilding metal)

[ubervamp]

Thanks guys for all your time and help!
Very interesting reading and links!
Much appreciated.

Answered all my questions

Cheers

Colin

[Jelly Terror]

Originally Posted by Neibelungen

Gilding metal as pointed out was a very high copper low zinc brass (usually 95/5) and has a colour that was more reddish yellow than brass.
One of it's main features was that it was softer than common brass (65-70/35-30) and flowed and moved better in an annealed state than normal brass.
Normal brass has a lower limit to it's 'flow' and would crack or split when the stress of die stamping passed a threshold point depending on the annealed state of the metal.
It's secondary quality was that because of the higher copper content it meant that gilding (either fire gilding with mercury/gold or gold electroplating) would adhere better to it

One of the main reasons for a move over to gilding metal was the slow change towards hydraulic stampings from the 1870's onwards, which has a different quality of pressure and metal 'flow' in a strike compared to striking in a drop hammer. Broadly speaking you tend to find the hydraulic process and dies work best on a shallower strike, but have a more uniform thickness, while a drop hammer will allow a bolder or deeper strike but make the metal more variable in thickness. The die cutting also reflected this as the former 'squeezes' the metal more and the later 'moves' the metal more.
One of the benefits of a uniform thickness was that piercing or trimming dies could be more effective and less prone to breakage (allowing the replacement of hand piercing) as the clearance between piercing punch and the die is related to the thickness and hardness of the metal. (too much gap and you leave a longer burr, too little and the stress on the die increases (deflection) and the metal cut becomes ragged or breaks uncleanly

The different colours you find on 'brass' badges often relates to cleaning, annealing or pickling processes involved in the manufacture as well as the metal composition.
Heat and acid pickles cause local surface depletion of zinc and or copper from the metal, giving it a more yellow or red appearance too. Zinc will dissolve or evaporate at a different rate to the copper at different heating ranges (from soldering lugs or annealing) or copper can brought to the surface in preference. (hence while the metal can be a uniform 95/5 mix, in local spots or the surface it can vary from 80/20 to 99/1).

(Standards for gilding metal composition were not set down in regulations till around 1904 and manufacturers could have a % or two variation as to what they defined as gilding metal)

Absolutely brilliant.

[KLR]

Yes, brilliant as usual - I've always learned a lot from Neib.

But you are wrong in stating that Standards for gilding metal composition were not set down in regulations till around 1904 .
In fact the Royal Army Clothing Dept Pattern 4480/1897 (TNA WO 359/6, 336) defines GM as 86.7% copper and 13.3% zinc by weight.
(can't remember the exact day in 1897 but will try to find it later)

[grenadierguardsman]

Excellent.....now i'm completely confused !
Andy

[Jelly Terror]

Originally Posted by grenadierguardsman

Excellent.....now i'm completely confused !
Andy

[2747andy]

A Victorian/Edwardian badge with all of it's "Factory Finish" intact! It has not been cleaned and in un-issued condition. Almost looks "staybright"?

Andy

[magpie]

Percentages for gilding metals.

[magpie]

Another

[ubervamp]

Could anyone please post a side by side comparison of a regular badge with "factory finish" and an officers "gilded" badge, as I'd be very interested to see the difference in finishes.

Thanks

Colin

[ubervamp]

Could someone confirm that this RFC badge is not an officers badge (as I think they had a bronze/dark finish?) and that the finish remaining is, in fact, not gilt?

Thanks again

Colin

[Jelly Terror]

Originally Posted by ubervamp

Could anyone please post a side by side comparison of a regular badge with "factory finish" and an officers "gilded" badge, as I'd be very interested to see the difference in finishes.

Thanks

Colin

You wouldn't let it lie!

[Frank Kelley]

Those are actually RAMC and not RFC, the RFC badge in your post number seven in this thread is a good other ranks example.

Originally Posted by ubervamp

Could someone confirm that this RFC badge is not an officers badge (as I think they had a bronze/dark finish?) and that the finish remaining is, in fact, not gilt?

Thanks again

Colin

[Phil2M]

The finish on your RFC is, I think, the remnants of the factory finished gilding metal.

Phil