Andrew, the normal way to anneal alloy is to spread soap on the area concerned and then heat, (from the other side) with a blowtorch until the soap turns brown. Allow to cool and continue to form the alloy, repeat the process as required.
Mick
Should one heat ali sheet when bending it?
Should you only heat the sheet for compound curves?
How hot should it be?
Ally is so soft that i have never heated it and i don't know anyone who has.
Andy, I think most people who have used alloy for the rear panel will have annealed it around the compound curves.
Andrew, the normal way to anneal alloy is to spread soap on the area concerned and then heat, (from the other side) with a blowtorch until the soap
turns brown. Allow to cool and continue to form the alloy, repeat the process as required.
Mick
tried heating some duralumin sheeting (2.6mm) then hit it with the hammer and it shattered!!
quote:
Originally posted by DaveFJ
tried heating some duralumin sheeting (2.6mm) then hit it with the hammer and it shattered!!
Duralumin (wot Zepplins were made of) is from aluminium copper alloys it quench hardens from 500-550c indeed it continues to harden over several
days --- its not the heating that hardens and it but the high rate cooling from a very high temperature.
More "normal" aluminium alloys both age and work harden but nothing like to the extent of "Dural" Like Mix says gentle heating
followed by cooling puts it back into maleable/ductile state and gets rid of the stresses caused by working it.
an eletric hot air gun should provide just enough heat.
yes in hindsight a blow torch was a bit excessive....
pure ali is very soft & does not harden, whats called T4 is harder but will anneal with heat as described above & does not work harden if you raise the temp enough, T6 is even harder but again can be annealed at the right temp, to harden it again you need to accurately controll the temp & the quenching