shop-talk
[Top] [All Lists]

Re: Copper gaskets

To: rwil@cts.com, shop-talk@autox.team.net
Subject: Re: Copper gaskets
From: LBC286@aol.com
Date: Fri, 15 Nov 2002 13:00:21 EST
In a message dated 11/14/02 1:29:48 PM Pacific Standard Time, rwil@cts.com 
writes:

> 
> 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.
> 

- - - - - - - - - -

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 
molecules
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 
and
become more flexible.
It does work harden fairly quickly as well but this property isn't being 
used.
When you are heating it try to keep it on a flat straight surface!  If you 
are
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 
with
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 
cooking
and you don't have to drop it.

Alan - try it with a couple of bits of scrap copper, one cooled slowly and 
the
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
compression fitting!"


Thanks again,

Allen Hefner

///  unsubscribe/change address requests to majordomo@autox.team.net  or try
///  http://www.team.net/mailman/listinfo
///  Archives at http://www.team.net/archive/shop-talk


<Prev in Thread] Current Thread [Next in Thread>