On the subject of annealing I agree with you and CooperMan, as he says, you are guaranteed a perfect fit. My only point is, in the photo I referred to on Gomog showing the drain plug bolt, the washer appeared to be aluminium not copper. If that is the case according to the internet the way to check you have achieved the correct temperature for annealing aluminium is, first hold the component near to a lit candle to cover it with soot. Then when heating with a MAP torch wait till the soot disappears then allow the component to cool. Any comments?
Once again thank you to everyone for your replies.
Regards Tony
I would always choose copper as a plug sealing washer. It has the greater maleability over aluminium, being its ability to deform under compression. Copper also has greater ductility as well, its ability to stretch. If you've ever bent aluminium sheet in a vice to make a bracket you will have noted on the outside of the bend the metal tends to tear if the bend is tight whereas copper wouldn't.
