Annealing Copper Washers And Gaskets.

[tridentt150v]

Anneal=use a gas torch [or your mums gas stove], dangle the copper washer on a bit of thin tie wire, let it get cherry red with the heat, then dunk it in a cup of cold water. This process softens the copper and restores its sealing properties. A metallurgist will tell you that the heating and rapid cooling re-aligns the crystal structure in the metal.

It is [very] good practise to do this with all copper washers/gaskets before using them, even new ones should be done. The manufacture processes [metal rollers and metal stamps] tend to work harden the metal. Added to this the washers could have been bumped around when shipped out to the warehouse where they laid around for months in the atmosphere absorbing oxygen etc - this also adds to the hardness/brittleness. Annealing fixes all this up. Older cars and motorcycles [pre 1960's] regularly used copper head gaskets, manifold gaskets, washers etc, these gaskets were annealed and used again and again with every rebuild and worked fine.

As a test, try to bend your copper washer before you anneal and then try it again after you have annealed. Notice the difference? Afterwards the copper is heaps softer and ready to use.

The only time I would not recommend re using your copper washers and gaskets is if they have been used that many times that they are now too thin to take up the space.

[SteveL]

Actually 'annealing' is a process involving slow cooling following heating. Rapid quenching can induce stresses due to dimensional changes, but in small parts it will hardly matter. A metallurgist will tell you that, with copper alloys at least, annealing relieves the effect of dislocation motion and 'pile-up', which ultimately results in the work hardening effect and, at the extreme, fracture. Dislocations are defects in the crystal lattice.

Of course what annealing won't do is restore dimensions such as thickness (eg compression of a copper head gasket), which is why it's not an 'indefinate' process.