Aluminium annealing

[benofbrum]

I have just made a scuttle panel for my Excelsior from some old aluminium sheet of unknown hardness. A post will follow when I find out how to include pictures in a post. In the process I needed to do some metal bashing and annealed the sheet before starting. Many moons ago, an old toolmaker gave me this tip to gauge the correct temperature.
You firstly smear the area to be annealed with soap, using a dry bar of soap rubbed over the area. Then play a blowlamp over the area until the soap just turns black. Wash off soap and you are ready to bash.

[Stuart]

We used the soap trick too at school, when we were making ashtrays, I bet they don't make them at school any more.

[Hans Efde]

If you have hammered it, doesn't it look messy? How do you get it straight again? I suppose this is only necessary with alu alloy? I have sheets which I think is 99% pure alu. It's soft as a towel, I can't imagine it getting age stress cracks.

[benofbrum]

The areas hammered don't show when the bonnet is closed. Mine is a touring car, not a show car. It has probably done more miles the other side of the channel than this.