[Amps] Bend allowance

Peter Chadwick g3rzp at g3rzp.wanadoo.co.uk
Thu Aug 4 04:42:52 EDT 2005


Ian asked:
>Staying on-line... what's the trick to prevent alumin(i)um from 
>splitting on the outside edge of a bend where it is stretched?


As Will said, use a softer aluminium. Or heat treat what you have. Problem is that that heat treating aluminium is a pretty specialist subject needing good heat control. However, I have successfully managed to soften some aluminium sheet of unknown mix (obtained cheap at a model engineering show) by the old trick of rubbing some soap on one side, and heating the other until the soap turns brown. This approach works pretty well, and allowed bending without cracking. Don't heat it too much, though, and remember that some hard alloys have a lot of magnesium in them. Once they catch fire, you have problems, and water isn't the way to put the fire out. Just enough heat to turn the soap brown is what's needed. Liquid soap is easiest to use. A paint strippping heat gun might do - I've used that successfully, as well as a propane gas torch. If you can get one, the old fashioned big brass blow lamp fired with paraffin (kerosene)  is good, but could be too fierce.
As for bending radius - I just look it up in my Zeus engineer's charts........

73
Peter GW3RZP/P this week.


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