[Shop-talk] Annealing Copper bars
Donald H Locker
dhlocker at comcast.net
Sat Aug 8 11:13:33 MDT 2020
The temperature that the copper reaches is controlled by the rate at
which the heat escapes it vs the rate at which heat is added to it, and
finally by the temperature of the flame.
An oxy-fuel torch adds heat quickly, so the rate at which it is lost is
less of a problem. Propane/air is not as hot as oxy/fuel, but they're
both plenty hot enough.
I would expect a propane torch to do OK as long as your copper bar is
reasonably well insulated from the outside world - how about [nearly]
burying it in vermiculite? Add heat in the middle with the rest of the
bar pretty well buried and it should get reasonably hot throughout. You
could use a Tempil Stik or an IR thermometer near the ends to see when
it has heated sufficiently.
It would be easy enough to then pick up the bar with pliers or tongs and
dunk it.
At least I'd try that before tempting the fates with Mrs. Jack's oven.
Donald.
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On 2020-08-08 12:06 p.m., Jack Brooks wrote:
> I disagree to some extent on the water/oil quench vs. air cool, from
> text and experience. I’ve done both with oil pan drain plug washers and
> while there may be a difference, it’s minor making the two methods
> interchangeable in my experience, especially if I am trying to go from
> half hard to a softer condition. A quench is the ultimate way to
> soften, but just getting it up to temperature makes a huge difference in
> hardness.
>
>
>
> https://en.wikipedia.org/wiki/Annealing_(metallurgy)#:~:text=In%20the%20case%20of%20ferrous,quickly%20by%20quenching%20in%20water.
>
> https://www.wikihow.com/Anneal-Copper#:~:text=You%20quench%20carbon%20steel%20to,the%20resulting%20crystalline%20structure%20is.&text=So%2C%20to%20anneal%20a%20hardened,heating%20it%20red%20anneals%20it.
>
> The question remains, lacking an Oxy torch, thoughts on the clean cycle
> of a home over or any other suggestions? I may talk with my body guy
> about using his Oxy torch. That was a good suggestion.
>
> Thanks,
> Jack
>
> *From:* Shop-talk <shop-talk-bounces at autox.team.net> *On Behalf Of *Pat
> Horne
> *Sent:* Saturday, August 8, 2020 8:44 AM
> *To:* John Innis <jdinnis at gmail.com>
> *Cc:* shop-talk <shop-talk at autox.team.net>
> *Subject:* Re: [Shop-talk] Annealing Copper bars
>
> So, referring back to the OP about using the oven to anneal the bars, it
> WOULDN’T be a good choice.
>
> Peace,
> Pat
> Pat Horne
> We support Habitat for Humanity
>
> On Aug 8, 2020, at 10:03 AM, John Innis <jdinnis at gmail.com
> <mailto:jdinnis at gmail.com>> wrote:
>
> This matches my understanding as well. Brass and copper soften when
> quenched. Steel and Aluminum harden when quenched.
>
> On Sat, Aug 8, 2020 at 9:59 AM Bob Spidell <bspidell at comcast.net
> <mailto:bspidell at comcast.net>> wrote:
>
> Could be (the plot thickens):
>
> "Annealing copper makes it softer and less brittle, which allows you to
> bend it without breaking it. This malleability allows you to hammer and
> mold the copper into any shape you wish without cracking the metal. You
> can anneal any grade and thickness of copper as long as you have a
> flame
> that can transmit enough heat to the metal. The most straightforward
> way
> to anneal copper is by heating it with an oxygen acetylene torch and
> rapidly cooling it in water."
>
> https://www.wikihow.com/Anneal-Copper
>
>
>
> On 8/8/2020 7:43 AM, Pat Horne wrote:
> > Maybe you’re right & I’m wrong! Wouldn’t be the first time.
> >
> > Peace,
> > Pat
> >
> > Pat Horne
> > We support Habitat for Humanity
> >
> >
> > On Aug 8, 2020, at 9:33 AM, Bob Spidell <bspidell at comcast.net
> <mailto:bspidell at comcast.net>> wrote:
> >
> > Well snap. I've been doing it wrong all these years I've reused
> copper, mostly on sealing washers for oil pan plugs.
> >
> > Thanks for the reply.
> > Bob
> >
> >
> >> On 8/8/2020 7:21 AM, Pat Horne wrote:
> >> I thought quenching made the metal less soft.
> >>
> >> Annealing requires slow cooling.
> >>
> >> Peace,
> >> Pat
> >>
> >> Pat Horne
> >> We support Habitat for Humanity
> >>
> >>
> >> On Aug 8, 2020, at 9:18 AM, Bob Spidell <bspidell at comcast.net
> <mailto:bspidell at comcast.net>> wrote:
> >>
> >> Question for the List: Is it proper to quench--in water,
> presumably, or oil maybe--copper to achieve softness after it's been
> heated 'cherry red?'
> >>
> >> Bob
> >>
>
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