Talk:Bronze

Density of Bronze

What is the density of bronze? Thanks, --81.86.68.253 (talk) 18:20, 24 February 2008 (UTC)

According to this site, the densities for the following types of bronze are:

Bronze, aluminum: 7.7

Bronze, 7.9 - 14% Sn: 7.4 - 8.9

Bronze, phosphor: 8.88

Markekeller (talk) 03:46, 15 May 2008 (UTC)

Arsenic

I've removed the implication that arsenic bronzes are necessarily naturally occurring - it's highly contentious, and outside of Mesopotamia (e.g. in Pre-Colombian America), almost certainly untrue. -Spikeyi

Does Bronze oxidize

This article indicates that Bronze does not oxidize, which, according to the Historical Preservation Technical Procedures index (http://w3.gsa.gov/web/p/hptp.nsf/035c614b995c0406852565d1006211b3/6c8c800d5618e023852565c50054b2c6?OpenDocument), is not true. The patina that bronze develops is part of the oxidization and sulphurization process--not a replacement of it.

Phosphor bronze

Acoustic guitar strings and electrical components' contacts are often described to be plated with "phosphor bronze". Any information or references about this? --blades 00:05, May 16, 2004 (UTC)

Category

Does this need to be in the 'metals' category? It's already in alloys which is a subcategory of metals. -David 04:50, Oct 21, 2004 (UTC)

Harder vs. durable

Is there a difference between bronze being harder and more durable than stone or is the latter a consequence of the first? MarSch 13:15, 6 Apr 2005 (UTC)

Brass vs. Bronze

The brass article seems to imply that, while some brasses are called "bronze", this is incorrect:

Some types of brass are called bronzes, despite their high zinc content.

On the other hand, this article indicates that "bronze" is a general term for copper alloys, and therefore includes brass:

brass, a subset of the bronze alloys in which zinc is the principal additive

I am not qualified to judge which of these is correct, but they seem to contradict each other.

Similar comment posted on Talk:Brass.

— Nowhither 00:20, 25 August 2005 (UTC)

I guess its a wide/narrow use of the word. The narrow definition is bronze=Copper+tin+(impurities). The wide definition is of Copper+something. dic def Zeimusu | Talk page 13:18, 2005 August 25 (UTC)

In France you may call your casting bronze as long as it has a 60% copper content. They tend to call this artisan bronze in the UK as it is more brassy in colour, although not quite as yellow as brass. It is true that English bronze is much darker in colour. The reason for the difference between the English and French bronze is that the French would and still do in some cases, chisel, or chase the hardware, etching in the details that traditional sand casting would lose. Lost wax casting tends to mend the loss in detail, although, the chasing adds to the allure as it is handmade, and the imperfections are apparent and appreciated. Superfinicky —Preceding undated comment was added at 21:19, 19 January 2009 (UTC).

There is some good info here: http://www.metalcastingdesign.com/content/view/108/203/ For example: Bronzes "Bronze is an imprecise term. It originally referred to alloys in which tin was the major alloying element. Under the UNS system, the term bronze (C86100 to 87800, C90200 to C95900) applies to a broad class of alloys in which the principal alloying element is neither zinc nor nickel. Nevertheless, bronze is the common name for a number of alloys that contain little, if any, tin." —Preceding unsigned comment added by 74.237.247.85 (talk) 01:31, 2 May 2009 (UTC)

Bronze vs. Iron

I thought bronze is weaker than iron. What causes this difference? 66.195.132.2 13:06, 18 October 2005 UTC

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Bronze is stronger than simple iron, but weaker than carburized iron. In the ancient period, therefore, bronze was stronger but more expensive than iron. As ironworking techniques improved, iron took over bronze, being both cheaper and stronger. Also, unless I'm mistaken, bronze has a lower melting point than iron and is therefore easier to cast, but harder to forge due to its greater hardness. —Simetrical (talk) 20:47, 18 November 2005 (UTC)

Regarding:

Bronze was also stronger than iron, another common metal of the era,...

This does not sound right to me - to which era is the article refering? I guess that there might have been a period in the late bronze age when small amounts of iron were being used and this iron may been weak due to impurities etc. I would like see some cites for this. Bronze has a much lower melting point than iron and it was quite impossible for the ancients to cast iron. Bronze is far more maleable that iron and bronze artifacts sometimes have beaten details that could never have been achieved in iron. See Yetholm-type shields for example.

Regarding the statement:

As an example, Roman officers were equipped with bronze swords while foot soldiers had to make do with iron blades.

To what period of Roman history does that apply?

Another questionable statement:

Bronze also has very little metal-on-metal friction, which made it invaluable for the building of cannon where iron cannonballs would otherwise stick in the barrel.

Bronze is often used for bearings, but I don't think that has anything to do with cannons. Early cannons did not fire tight-fitting balls which were, in any case, often made of stone. If the above is true, why arn't modern guns which do have tigh-fitting ammunition, made of bronze? My understanding is that early cannons were made of bronze because of the adaptation of bell casting techniques were the only practical method available.

Methinks this article needs some work... Gaius Cornelius 01:08, 23 November 2005 (UTC).

I agree with Gaius Cornelius. Although I found evidence that when lubricated, brass has a lower coefficient of friction (in contact with steel) (see http://www.carbidedepot.com/formulas-frictioncoefficient.htm) when clean, cast iron has a lower coefficient of friction (in contact with cast iron) (see http://www.engineeringtoolbox.com/friction-coefficients-d_778.html) Kiujhytg2 —Preceding undated comment was added at 18:01, 6 October 2008 (UTC).

This says that "Iron is not superior to bronze for tools. Wrought iron, the form first encountered by Near Eastern smelters, is roughly equivalent in hardness to annealed 10% tin bronze, and inferior to all cold-worked tin bronzes. It is only when carbon dissolves into the iron (carburization) and the artisan quenches the resulting steel that ferrous metals have a definite hardness advantage over bronze." No mention of when carburization was discovered, though, do you know? Partial carburization was certainly possible during early-mid Roman times, but I don't know at what point iron surpassed bronze in price or strength. —Simetrical (talk) 02:27, 23 November 2005 (UTC)

Well, when you take into account that the period where 90% of the tools were iron was in the 10th century BC, I think we can safely say that bronze was surpassed by iron in terms of cost at that point, and hardness equality would follow. This is long before even the beginnings of a Roman Senate, so I seriously doubt that Roman officers (Centurions or whathaveyou) were equipped with bronze weapons when the Romans did have access to steel, and used it in their swords. It is also my opinion (and only that) that (HC) steel is a superior sword material because once properly tempered it has good edge retention but is still nice and springy.

As far as cold-working bronze vs iron goes, I can safely assume that would create alot of stresses in the metal (it does so for iron or steel, anyway), making it very hard, yes, but very brittle too. That is not the sort of thing you want in a tool like a scratchplough or a nail. Instead, toughness is much preferred. Alej

Wrought iron is weaker than bronze, but bronze is weaker than steel (which is an alloy of iron with between 0.02% and 1.7% carbon). People often get this confused, because they don't distinguish between wrought iron and steel (they just refer to both as iron). I have made changes to this article and several others to avoid confusion on this subject. Note that people made tools from bronze before they figured out how to make them from iron because iron's melting point is higher than that of bronze or its components, which makes it more difficult to make tools from iron. Then eventually they switched from the bronze age to the iron age, in which most things were made from wrought iron, despite the fact that it was weaker than bronze. But they only switched because iron was more common and cheaper, and even after they switched, the best things were still made out of bronze (or better yet, steel, although steel was difficult to produce with the methods available at the time). - Shaheenjim 19:11, 14 June 2007 (UTC)

Regarding the statement that "bronze is stronger (harder)[2] than wrought iron", where reference [2] is a link to this PDF: I believe the document in question does not support that claim. It appears to state that, aside from the inferior early "unintentionally alloyed" bronzes, wrought iron and "highly alloyed" bronze were roughly similar in terms of hardness (see figure 2). I'm not disputing the claim, merely suggesting that the reference is incorrect. I'll replace it with a 'citation needed' tag. — Wisq (talk) 20:28, 6 February 2008 (UTC)

Composition

This article does not contain the usual composition of bronze, which a quick google:define turns up as 60% copper to 40% tin. I'll pop this up.

80.2.26.219 20:29, 18 November 2005 (UTC)

That sounds like far too much tin. Anything around 10% tin would be considered a high-tin bronze. 62.239.24.22 13:16, 24 November 2005 (UTC)

That composition would be Speculum which was used for coin making in Roman times (in Gaul and Britain anyway) --Nomiro 11:25, 9 November 2006 (UTC)

40% is way too high. The (approx.) 23% tin of the bronze used in Indonesian gamelan and the similar tin content of bell metal are the highest tin contents in regular use, apart from speculum metal. In engineering applications, 18% tin is around the upper limit for a high-tin bronze. 40% tin is therefore not 'typical'. There is really too much variation among bronzes for any 'usual composition' or 'typical' figure to be given. And brasses and bronzes are two separate families of copper alloys. EEye 12:04, 27 March 2007 (UTC)

Surely, both the ancients and moderns used lead along with the well known copper tin-alloy. Lead makes for easier casting and in modern times, easier machining. 10% seems common, more or less is less common.--Alphasierra (talk) 22:28, 13 September 2008 (UTC)

English

"Bronze" is English, but not that anciently. I've modified the statement.

Origins

The Bronze Age article states that bronze was developed by the Maykops (see Maykop culture). Is there a reason why this article states differently? --Brunnock 14:05, 2 February 2006 (UTC)

The article says - Phoenician traders visited Great Britain to trade goods from the Mediterranean for tin.[citation needed]- Quite right, a citation is needed and some evidence that the Phoenicians did any such thing. --Alphasierra (talk) 22:38, 13 September 2008 (UTC)

Patina vs. oxidation

I am quite sure that the patina of bronze is formed by oxidation, so the statement "While bronze forms a patina, it does not oxidize" is incorrect. Will someone else confirm this?

Patination composition varies with the reacted elements and will determine the color of the patina. Exposure to chlorides leads to green, while sulpher compounds (such has "liver of sulpher") tend to brown. Patination is deliberately accellerated by heat. Colors range from matte sandstone yellow to deep blues, reds and various blacks, sometimes with the surface sheen enhanced by waxing for artwork displayed indoors. - Leonard G. 18:44, 31 December 2006 (UTC)

Patinating bronze is a process of heating the bronze up and applying a patina which is absorbed by the porosity of the metal, which once cooled down, fuses with the surface, thereby accelerating what would be a natural process. There are some who apply oil based patinas without heating the metal, which leaves a patinated look, without the oxidization. This is more of a superficial attempt at antiquing a casting. Another way would be to drop the piece in acid and let the acid eat away, oxidizing the surface. This may leave a greyish hue on the surface which can be degraded using steel wool. You will still need to heat the castings in order for the surface oxidization to fuse with the metal. This further changes the colour, and brings you back to a more brownish bronze. Superfinicky —Preceding undated comment was added at 21:26, 19 January 2009 (UTC).

Expanding slightly just before they set?

"Common bronze alloys often have the unusual and very desirable property of expanding slightly just before they set, thus filling in the finest details of a mould"

I don't think this is true. Has anyone a source? As far as I know, liquid to solid shrinkage of about 5% occurs with copper and most of it's alloys. This can be offset by regulating the oxygen content which will allow microscopic bubbles to form, which will offset some of the shrinkage. But I don't think you can get it to expand....

--Nomiro 11:15, 9 November 2006 (UTC)

The addition of Bismuth to the bronze will produce an alloy that will expand upon cooling, as that is one of the properties of Bismuth. Like water, Bismuth is one of the few known substances which is more dense in its liquid state than solid. There is evidence of a bronze with 18% Bismuth content cast by the Incans for just that purpose, a handle secondarily cast onto a dagger. Bg2 (talk) 02:18, 11 January 2009 (UTC)BG2

A list of civilizations

It would be good to list civilizations and their usage of bronze.--HalaTruth(ሀላካሕ) 08:25, 31 December 2006 (UTC)

Etymology

The etymology of "Britain" here given seems spurious - the cited page makes no mention, and the only other references I can find on the 'net (don't have any books handy) are mirrors of Wikipedia. Identical line in Brython, removing both. - Somnior 21:21, 30 January 2007 (UTC)

Proposed project

There is evidently no extant WikiProject which deals with articles concerning alloys and other chemical compounds. This could be a problem, as many of these articles deal with what are considered to be generally important topics. To correct this situation, I have proposed a project to deal with these articles at Wikipedia:WikiProject Council/Proposals#Chemical compounds and mixtures. Anyone interested in contributing to such a project should indicate as much there. Thank you for your attention. John Carter 20:35, 28 April 2007 (UTC)

Roll back of precision

My correction to one part of this article was rolled back on the grounds that the original was more precise and still true. I have read through all these comments and find that arguements against many of the things I pointed to exist here. My change was more precise and included a citation and the editor said he did not understand why I did it when it was explicitly stated in the remark: Every single following paragraph contradicted the summary statement at the beginning. After my experience with a Glass posting where a totally wrong statement was preserved by some vulture watching it, I am certainly not going to waste my time on this. One of the reasons the 1911 Encyclopedia Britanica is famous is becouse the articles were written by people who did the original research. Yet Wiki has no mechanism for publication by authorities who must be published elsewhere and hopefully referenced here, if not taken off. Silly. Mike1942f 01:49, 1 July 2007 (UTC)

For other people, note that the thing he changed, which I reverted, said, "With the exception of steel, bronze is superior to iron in nearly every application." I don't see which of the things in the following paragraphs he thinks contradict that. The following paragraphs don't even mention iron again, except for one time. And that's only to say that iron doesn't make for good cannonballs. That supports the thing he changed, it doesn't contradict it. - Shaheenjim 09:40, 1 July 2007 (UTC)

Information Taken From Bronze-Statues.us

I've found that much of the info in the 'Properties' section of this page comes from the following webpage:

http://www.bronze-statues.us/bronze_q.html

Ought this to be removed? Much of it seems to be questionable/unsourced. Markekeller (talk) 03:34, 15 May 2008 (UTC)

Ummm, that page is very obviously an automatically-generated spamfarm. Chris Cunningham (not at work) - talk 18:43, 21 December 2008 (UTC)

External links removed as spam

I'm all for removing clear spamlinks, but I think that two of the links recently removed by Vsmith provide solid "for further reading" information. I propose to bring back 19th-century bronze sculpture sand casting because it provides many interesting tidbits that don't necessarily belong in the main WP article, and "Flash animation of the lost-wax casting process". James Peniston Sculpture. {{cite web}}: Cite has empty unknown parameters: |1= and |coauthors= (help), which offers a good animated primer on casting bronze. I'd also delete "Lost Wax, Found Bronze": lost-wax casting explained as redundant and not terribly well done. PRRfan (talk) 14:50, 31 December 2008 (UTC)

Bronze.galleries.com and the James Peniston sites are commercial sites selling statues and books - promotional. The wildlifeart.org is a noncommercial site. Please see WP:EL. Vsmith (talk) 00:27, 1 January 2009 (UTC)

As you no doubt know, WP:EL has no blanket prohibition on links to commercial sites; instead, the guidelines are more subtle. They allow, for example, links to unique content that cannot (for copyright or other reasons) be replicated on WP. The James Peniston animation is such a piece of content. I don't know of any site, commercial or otherwise, that offers such a clear explanation of the casting of bronze. The argument for bronze-gallery.com may be a bit weaker; to paraphrase WP:EL, much of its content could appear in the Bronze article if it were expanded to Featured Article quality. But it also contains plenty of facts about bronzework that are likely too picayune for WP, yet potentially of interest to those who visit the article. PRRfan (talk) 01:25, 1 January 2009 (UTC)

The animation is linked at Bronze sculpture where it is more relevant than this general bronze article. If others feel the gallery site is needed here - OK (also more relevant on the sculpture article), I'm wary of commercial promotion links and tend to reject sites that hawk their products - even if otherwise informative. Vsmith (talk) 01:46, 1 January 2009 (UTC)

Source found, sortof, for Bronze being harder than Wrought Iron.

Searching for a source on bronze being stronger than wrought iron, I came across this article: Ancient Blacksmiths, the Iron Age, Damascus Steels, and Modern Metallurgy. It includes a chart (figure 2, at the end of the pdf) that demonstrates that lists Cold or Warm forged bronze is better than annealed iron, but that's not quite the same thing as saying "bronze" as a whole, is "better (harder) than iron". I'm not a metalurgist or a historian myself, so I don't fully understand the timeline of metal quality given here. Could someone help out a bit here? Fieari (talk) 02:00, 2 January 2009 (UTC)

Spotted weasel word

Under "Properties", it reads that "Bronze can be superior to iron in many applications". It's not specified, though, what "many" includes - it looks to me like a weasel word. Since I'm not an expert on the subject, I'm hesitant to edit it myself...does anyone else have an opinion on the matter? 76.71.34.180 (talk) 00:37, 1 June 2009 (UTC)

Copper Dispute?

Found a comment in the article: "<!-- Disputed - Copper? => (of which Ötzi the Iceman's axe is an example)-->". I thought he was accepted to be simply chalcolithic/copper age. Is this actually disputed? My first thought was to remove it, but I didn't want to interfere in a dispute. ― Darekun (talk) 21:21, 15 July 2009 (UTC)