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Re: [Shop-talk] Annealing Copper bars

To: Jack Brooks <>
Subject: Re: [Shop-talk] Annealing Copper bars
From: Donald H Locker <>
Date: Sat, 8 Aug 2020 19:02:18 -0400
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Cool! (so to speak.) I would have thought more insulation would have
been required, but it sounds like that is sufficient.

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On 2020-08-08 6:50 p.m., Jack Brooks wrote:
> Insulation - BINGO!  Great thought Donald!
> I underestimated copper's heat transmission rate.  Using propane, I could not 
> get a 1/8 x 1 inch x 8 inch bar to get to glow with the bottom of the bar 
> clamped in a vice.  I decided to try "Insulating". 
> I laid a 3 inch long copper bar (typical busbar length) across the teeth of 
> two sections of a coarse hack saw blade clamped off to the side of my vice.  
> There is almost no contact between the copper bar and these supports, only 
> across the tips of the teeth on the two halves of the hack saw blades, so 
> maybe a dozen pinheads.  With this arrangement and with a partially-dark 
> room, I could just barely see the red glow in the copper. After a quench, the 
> copper bar was soft!
> I now have a method.  Now I have to insure that I can clean up the contact 
> surfaces well without affecting the flatness and I can go forward with 
> softening the real busbars.
> Thank you everyone for a fun adventure in learning,
> Jack
> -----Original Message-----
> From: Donald H Locker <> 
> Sent: Saturday, August 8, 2020 10:14 AM
> To: Jack Brooks <>
> Cc:
> Subject: Re: [Shop-talk] Annealing Copper bars
> 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.  Iâ??ve done both with oil pan drain plug washers 
>> and while there may be a difference, itâ??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.
>> 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 <> *On Behalf Of 
>> *Pat Horne
>> *Sent:* Saturday, August 8, 2020 8:44 AM
>> *To:* John Innis <>
>> *Cc:* shop-talk <>
>> *Subject:* Re: [Shop-talk] Annealing Copper bars
>> So, referring back to the OP about using the oven to anneal the bars, 
>> it WOULDNâ??T be a good choice.
>> Peace,
>> Pat
>> Pat Horne
>> We support Habitat for Humanity
>> On Aug 8, 2020, at 10:03 AM, John Innis < 
>> <>> wrote:
>> This matches my understanding as well.  Brass and copper soften when 
>> quenched.  Steel and Aluminum harden when quenched.
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