I stand corrected. Jim is right: heat copper washers and quench in water.
>From the "Dictionary of Aeronutical Terms": Annealing- A method heat treatment
in which a metal is softened so it loses some of its hardness and brittleness.
Steel is annealed by heating it to a specified temperature and allowing it to
cool very slowly, in an oven. Copper is annealed by heating it re-hot and
quenching it in water.
Good thing we always used new copper sparkplug washers. I would have done it
incorrectly. Dislexai strikes again.
Geoff Branch
'74 Meejit "Yellow Peril"
'72 Innocenti 1300 Mini
----- Original Message -----
From "jim hurd" <hurd at boernenet.com>
To: <spridgets@autox.team.net>
Sent: Wednesday, August 22, 2001 9:32 PM
Subject: Re: Somebody's wrong, but it ain't me
> > Here's what I know: on an aircraft engine, the sparkplug washers are
> copper.
> > Every time you replace a plug, you have to use a new copper washer, OR
> hang them
> > all up on a wire, heat them with a torch and let them air cool. I don't
> think
> > the point of this would be to make them harder or more brittle.
> > Geoff Branch
> > '74 Meejit "Yellow Peril"
> > '72 Innocenti 1300 Mini
>
> This is the preferred procedure for copper aircraft spark plug washers,
> however, immediate quenching in water is recommended. Heating to cherry red
> allows washer to return to its original conformation, quenching keeps it
> from becoming brittle. This sounds counter-intuitive but A&P mechanics
> assure me it is correct.
>
> Jim Hurd '75 Midget
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