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I Forge Iron

Forging Naval (manganese) Bronze


Fe-Wood

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I was forging some naval bronze for the first time the other day. Well I should rephrase that... I tried to forge it. I got it hot to the point I could just see color and started to move the metal. It cracked all over the place. Not just where I was hitting it but also about 3" away toward the cool end. Anyone have any thoughts?

I was in the shade, outside, using a coke forge. My heat was a bearly perseptable red.

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Thanks Frosty-
Sorry to hear your luck was as good as mine:(
Boy, I was hoping for some good insight. I've done a "little" forging with Everdure that worked out OK. I understood Naval bronze has more zinc in it than Everdure which makes it harder to forge. I just spent a few minutes looking at the charts for this stuff and realize I don't "really" know what it is. I was given a box of old deck stanchions from a sailboat... "I think its Naval Bronze". I was told...

Just to be sure, when heating something with zinc in it to red heat, the zinc will leave a white/blue halo at the hot/cold transition zone, right? I try not to melt to much stuff with zinc in it very often:rolleyes:

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You have to get zinc to med high orange before it will burn. Lots of brasses forge quite nicely.

The Everdure I was playing with was from old sprues, gates and such so I'm pretty sure it wasn't as originally specced. I do know some bronzes forge very well, I just don't know which ones.

Frosty

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Silicon bronze (655) is easiest to forge. Did some yeaterday at heat ranges from dull red to cold (outside, bright sun, gas forge). Naval bronze will also forge well.

Fe-wood, I seriously dought you had naval bronze. Not sure what it was. Just being on a boat doesn't mean it is naval bronze.

Frosty, everdure is for the most part silicon bronze. Too hot maybe, as Thomas suggested? Also, as bent iron suggested, cast can be more difficult. I had some rail parts cast, knowing I would then bend them to lefts and rights (too cheap to carve two patterns). When I told the founder (mill spec), he was quite surprised that I could work the stuff. I had him make an extra fitting, and experimented with it first. I suspended the part on a fire brick, with some hanging off, then set the flame to it. As it stated to show color, it bent down from it's own weight. When it got to the melting point, it became hot short and broke off. Having learned the color spectrum this way, I knew my limits.

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I was reading an article on brass vs. bronze and it was interesting to note that most of what we call bronze today is actually brass. Bronze is a tin based alloy while brass has no tin but zinc. True bronze is rarely available in the market today and most of we as metalsmiths use as bronze is really brass of some alloy or another. When I was doing a lot of "bronze" casting I was using a silicon bronze(brass) that was so much easier to use than the traditional Italian bronze that most shops were using in the 70's but was it ever hard to get a patina on. I could get extruded wire in various sizes that could be forged hot or cold if annealed frequently and use as filler rod for welding up holes. It was great for fabricating spear shafts and other items that were difficult to cast. I felt like I was lying when I said it was solid "bronze".

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Actually the terms bronze and brass are so terminally muddled commercially these days that they are not used for specifics and are often lumped into "copper based alloys"

You can find brasses with tin and bronzes with zinc and weird admixtures like silicon bronze or Be Bronze

You pretty much have to get a spec to see what you actually have and even then mix-ups in the storeroom have happened!

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Arftist, The "bronze" I was pouring at the time had neither tin nor zinc. I can't remember the alloy number but the supplier's data sheet listed neither of them. It poured like water, wonderful stuff to cast with. It was a copper based alloy alright because at the top of the data sheet it said a copper based alloy with silicon. I was reading an article on Early Anatolian Bronze Age and it was describing the bronze as two distinct types in the region. The first was an arsenic based copper alloy with traces of zinc, lead, silver and iron oxide, that was the most common type and the second was a tin based copper alloy that was found only in high status burials. The tin based bronze was a trade item from outside of Anatolia, Syria, while the arsenic bronze was of local manufacture. By the time you finish the article they are calling one a brass and the other a true bronze. Got to watch these academian nuts you know.:rolleyes:
Oh, by the way Rio Grande Jewelry Supply in NM sells a tin based bronze casting grain for jewelers. Contains no zinc.

Edited by Bentiron1946
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Thanks for all the input guys. As some of you may have suspected and others figured, it turns out to be a brass veriety. I compaired my pieces to some 655 bronze and my stuff is much yellower and lighter in color. I just did a quick google on "bronze specs." and came up with around 50 verieties of brass and bronze from one source.

Good thing this stuff works great for spinning tools or I'da been hauling it around for 15 years for nothing.

Arftist: good tip on the "color" test. Everdur goes from a working temp to melting temp real quick. Almost found out the worst way...

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