Originally Posted by
Bend alot
...I hope you all check your invoice/s for the cost of the new washer/s. I have only ever seen one place that has had them, most places anneal the old ones (not sure what the manufactures or AMM call for). ...
I replace the washers every time. At around 50 cents each, I don’t see the point of reusing.
Annealing is, at least according to this manufacturer, a ‘no no’:
http://www.championaerospace.com/ass...ical/95-11.pdf
Tempest says use new every time:
https://m.aircraftspruce.com/catalog...tplugmaint.pdf
This is an interesting tit bit (with my bolding) from mechanic support dot com:
A spark plug gasket is a good example of using the joint material properties to advantage. Spark plug gasket forms an air-tight seal by using the work hardening properties of copper. A new gasket is soft and as the plug is tightened, the copper yields and flows into small gaps creating an airtight seal. As the copper deforms it gets stronger by a process called 'work hardening". Hardening prevents further yielding and this prevents the spark plug from loosening in service.
One reason to always replace copper gaskets is that once deformed and work hardened, it must be returned to the soft (annealed) state before it can again flow into the small gaps. Annealing will soften the copper but it won't restore its original shape.