In a message dated 11/14/02 1:29:48 PM Pacific Standard Time, email@example.com
> Non ferrous metals anneal by heating and then quick cooling, such as
> dunking in water. They are the reverse of ferrous metals in this
> regard. Copper and brass are the two I know best.
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Thanks for all the replies on the copper gaskets. You all seem to agree on
the procedure. I received the reply below on the other list. He seems to
think that copper gets brittle if cooled quickly. Any comments?
"Cool your copper gasket slowly, if you allow it to cool quickly the
in the metal will freeze in the heat-excited location they are in and it can
be in a brittle state. If you allow to cool slowly (the chap who mentioned
the heated bricks was going along the right lines) they will tend to align
become more flexible.
It does work harden fairly quickly as well but this property isn't being
When you are heating it try to keep it on a flat straight surface! If you
using a metal (iron) block to rest it on and that has got warm after heating
place a bit of heat insulation around it to slow the heat loss down. If you
are doing it in an oven just leave it in for half an hour after turning off.
If you are doing it with flame give it a little keep warming breathing on
the flame every couple of minutes for 20mins or so.
Basically you want the molecules within the metal to break their current
location/bonds, jump around a bit and cool down in a relaxed state. Slow
cooling achieves this.
In metal terms it is cold when you can pick it up without your fingers
and you don't have to drop it.
Alan - try it with a couple of bits of scrap copper, one cooled slowly and
other quenched. Then bend both bits the same amount several times and see
which one breaks first! The quenched one is partially brittle (or work
hardened without the work) before bending and should split before the slow
cooled one. OR, ask a plumber which joint snaps first, a soldered one or a
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