Recently PUB seemed to be a bit unsure on this subject so here are words of wisdom ( ?) f rom a very old engineer. To anneal aluminium, a small blowlamp i s f i ne. Put a bit of soap on the ally and heat i t up till i t turns black, then quench i n cold water. As Clive says, repeat as required. When annealing copper i t ’s the same, but needs to be much hotter. Annealing steel, you heat to red and l et i t cool SLOWLY.