Re: Primaries and Copper Tubing

Subject:     Re: Primaries and Copper Tubing
      Date:  Wed, 23 Apr 1997 10:08:49 +0000
      From:  Chris Gardner <gchristo-at-clt.mindspring-dot-com>
        To:  Tesla List <tesla-at-pupman-dot-com>

Tesla List wrote:
> Subject:       Re: Primaries and Copper Tubing
>        Date:   Tue, 22 Apr 1997 07:44:26 +1200
>        From:   "Malcolm Watts" <MALCOLM-at-directorate.wnp.ac.nz>
> Organization:   Wellington Polytechnic, NZ
>          To:    tesla-at-pupman-dot-com
> Gary,
>        The last time I had to anneal copper tubing I had to heat it
> cherry red with an oxy-acetylene torch.
> Malcolm
> <snip>
> > You can remove the work harden from the copper tubing with heat.  If
> > your
> > kitchen oven has a self cleaning setting put the roll of copper tubing
> > in the
> > oven. Set your oven to clean for the recomended length of time, usually
> > about
> > 3 hours. The work harden will be removed and the copper will be dead
> > soft
> > again.
> >
> > Gary Weaver

In blackmithing this is reffered to a the 'critical heat', for iron and
steel its a mild cherry red, bright enough to be seen in a well lighted
shop, its around 1400 to 1600 degrees. Ideal annealing is acheived by
reaching this temp. and placing the item in a trash can filled with
vermiculite, cooling in this manner can take up to 24 hours based upon
the mass of the piece.
I do not know what the crit. heat is for copper, but the controlled
cooling is just as important as reaching that temp for ideal annealing.