# Can you anneal brass like copper?



## Eric The Viking (20 Aug 2020)

I have some thick-enough pieces of thin brass sheet (formerly striker plates for door locks), that I can re-purpose for new locks (which didn't come with the correct plates!), but I will need to flatten and re-bend them.

I know that copper anneals pretty easily, just by heating and then allowing to cool - I do this when plumbing. Can I use the same approach with brass? The thick stuff is about 1.25mm thick and the thinner stuff 1mm.

Thoughts welcome.

E


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## Rorschach (20 Aug 2020)

Yes you can anneal it like copper, it doesn't get as soft as copper though and depending on the work you may need to anneal more often.


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## Phil Pascoe (20 Aug 2020)

Heat it til it's near red hot and quench it.


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## MusicMan (20 Aug 2020)

Quenching is actually unimportant for annealing brass and copper, slow cooling is just as effective, if not more. Quenching does strip off some oxide scaling though. 

The time when quenching is essential is when hardening steel.


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## AES (20 Aug 2020)

Agree with all the above. depending on the alloy, and the work you're doing - e.g. a lot of bending) brass will work-harden sometimes. So annealing more than once MAY be necessary.

I'm also not SO keen on water quenching after annealing. Although it does help with cleaning scale off, I just don't like the idea of the instant thermal shock - it MUST set up some tensions in the material surely?


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## sunnybob (20 Aug 2020)

Just check they are actually brass, and not brass plated steel. magnet test will do it.


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## MusicMan (20 Aug 2020)

AES is right, yes quenching does set up stresses and no need to do it in copper or brass, but not a biggie. And may be needed more than once, but once should be fine for a lock striker plate.

Steel will also soften with an anneal, in this case it must be slow cooled or it might harden. Though if it is brass plated, the plating may well come off if you get it hot enough to soften.

Keith (coupla degrees in metallurgy)


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## Phil Pascoe (20 Aug 2020)

I got used to quenching copper and brass because of being more used to working with silver, which does need quenching to soften.


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## MusicMan (20 Aug 2020)

Phil Pascoe said:


> I got used to quenching copper and brass because of being more used to working with silver, which does need quenching to soften.


Pure silver, Phil, or an alloy?


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## AES (21 Aug 2020)

Completely outside any knowledge or experience, silver for me.


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## Rorschach (21 Aug 2020)

I have never quenched silver when annealing. I don't quench anything when annealing.


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## MusicMan (23 Aug 2020)

Rorschach I think that is correct. Quenching should do nothing to help the softening process. Its purpose in metallurgical heat treatment is to (try to) preserve the high temperature structure. For pure metals this is a soft structure. There are two exceptions: steels (and some other rarer alloys), where a 'martensitic' transformation (a diffusionless shape change in the crystal structure) takes place on quenching, which hardens the material and age-hardening alloys, where solid-state precipitation takes place which hardens the alloy (e.g. duralumin and other aluminium-copper alloys). In the latter case quenching preserves the soft structure, so the material can be forged, then the alloy hardens at room temperature or in a low-temperature anneal. But I never like to disregard experimental evidence, which is why I asked Phil if his experience was on pure silver, or an alloy.


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## Rorschach (23 Aug 2020)

My understanding from what I was taught on my (fairly basic) silversmithing course was that quenching (non hardening metals) speeds the working process and doesn't do any harm, but doesn't do any good either.


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## MusicMan (23 Aug 2020)

Rorschach said:


> My understanding from what I was taught on my (fairly basic) silversmithing course was that quenching (non hardening metals) speeds the working process and doesn't do any harm, but doesn't do any good either.


Yes, this is generally true.


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## Phil Pascoe (23 Aug 2020)

MusicMan said:


> Pure silver, Phil, or an alloy?


Sterling. We were taught to anneal it if further work was required, the only time we didn't was when some hardness or spring was desired such as when making pins or clasps.


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## Steve Maskery (23 Aug 2020)

It never ceases to amaze me just how much knowledge and expertise there is on this forum about all sorts of matters unrelated to woodwork.


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## Rorschach (23 Aug 2020)

Since we are on the topic, you can anneal aluminium too which I do a fair bit, more often than silver or copper these days.
I used to struggle with it as it's very easy to overheat aluminium as it's annealing point is quite close to it's melting point. One day I watched a youtube video where I learned that sharpie ink de-natures at almost exactly the same temperature as aluminium anneals. So you scribble on your aluminium with a black sharpie, warm it up until the ink disappears (or turns pale yellow) and then let it cool down, the result is nice soft aluminium. It work hardens very quickly though so you need to do it quite often if you are (cold) forging it or spinning it.


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## AES (23 Aug 2020)

Not heard that one Rorschach (probably because there was no such things as a Sharpie when I was doing my apprenticeship )!

But we were taught that rubbing over the ali surface with ordinary hand soap (ideally a bit slimy so that it spreads easily) and then heating up until the soap turns chocolatey-brownish is a very good indicator of "Stop now unless you want to melt the ali"). It's a very useful tip if you do "play" with ali, especially if you are doing any bending, because depending on the exact alloy, ali generally work-hardens like the devil.

BTW, slightly off topic, but still on-topic-ish, as said above I know nothing about silver, except the fact that when using helicoil inserts in hot places (near but NOT on aero engines for example) those inserts are made of silver-plated wire to resist the higher temps). From the little I know about the general properties of silver I find that rather surprising - but then I'm definitely NOT a metallurgist.

@Steve Maskery: Yup, assuming your post above was not slightly disapproving (?), to me one of the biggest strengths of this Forum is that not only can one find a huge reservoir of wood working expertise (which in the main is freely shared around) but you can also find people who "know a bit" about all sorts of stuff, inc metalworking - AND again, almost without exception, people who are happy to share their knowledge to help others along.

Long may it continue I say.


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## Steve Maskery (23 Aug 2020)

Not disapproving at all! On the contrary!


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## Oddbod (24 Aug 2020)

I anneal the necks of brass rifle cartridge cases after three or four reloads, as they get work hardened in the resizing process.
Immediately after heating, they get dropped into water to stop the heat travelling too far down the case (annealed case heads is NOT a good thing...).


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