What IS Gunmetal?...

I have had gunmetal castings with a distinct greyish tinge, but easy to tell when you have them in your hand that they are in fact gunmetal. However maybe not so obvious from a poor quality picture in a magazine.

Chris Gunn (no relation)

That's true, even though the hue of the photos was a goldish tinge, they still looked grey under machining!

Martin

Gunmetal grey - the colour of old cannons that are well oxidised.

Admiralty gunmetal - a bronze used for casting cannons (and bits for model engines).

Russell

That's the odd thing about it all. That gunmetal is these days more associated with grey. It's always been a descriptive of a car colour or a fabric.

It's only metalworkers who tend to know that traditionally, gunmetal is a bronze.

Martin

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This monument in Belgium was cast from melted down captured frogite cannons during the battle of Waterloo.

But I think that a very dim view would be taken of anyone chopping bits off it to make model steam engines with though.!

Nick

I just asked my wife, who thought it was a liquid for making one metal look like another!

Bless her, she'll always come up original!

Martin

Nick, that LOOKS like bronze to me.

And did you say Frogite?

Martin

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Yeahhh, why.?

Nick

Is that where the term "Frog" comes from?

Martin

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Not sure. I always thought it was something to do with them eating frogs legs (which are delicious and like chicken) as they call Brits 'Roast beefs'

I presume that melting the enemy's guns down to make a victory monument was probably a gesture of wiping their eye and adding insult to injury. Would not happen now of course. Be far, far too un PC

Anyway, must have been a very big bonfire to smelt all that bronze. - I wonder if they got froggie prisoners to haul it up to the top.

Nick

Ah, so Froggite is one of yours?

Martin

Gunmetal must surely depend on the age and to some extent where it was made? I had a small interest some years ago in American civil war cannon, in particular naval cannon and at least some of these were made from (if I remember correctly) cast Iron wrapped with wrought iron hoops to help prevent them exploding.

Gunmetal is generally considered to be 85-5-5-5 bronze. That is an alloy of 85% Cu 5% Zn 5% Sn 5% Pb. ( Also known in some circles as Red Brass). As has been already mentioned it will turn greyish black not only when heated (as for silver soldering) but also it will come out of the mould greyish black when first cast. Normally cast gunmetal parts would then be pickled to get rid of this surface oxidation. Perhaps the ones you've seen have not been pickled?

John Purdy

I guess that's a possibility, John.

Mind you, for what some charge for castings I'd expect them to have been linished by Miss Worlds and polished with fairy dust!

Cheers,

Martin

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You keep mentioning the cost. - Perhaps you would find it more attractive to fabricate from raw stock.

Here is a clicky thing **LINK** to help you bypass the casting sellers and make your own from bronze. Don't forget you will need to add 20% to those prices for the dreaded VAT

Nick

Edited By Nick_G on 04/04/2016 20:03:44

Yes I do,

but that is a consideration. Some are much worse than others. But I take your point about the solid bar stuff. not that cheap either is it? But then I don't need a metre and I do have a lot of existing sheet brass for entablatures, etc.

Perhaps it's possible to buy odd castings separately.

For steel and ally I have a friendly local machinist who casts more into the skip than I'll ever need.

Anyway, this is a new hobby and there's much to discover.

Cheers,

Martin