If you ever tried to spot-weld two alu sheets, the welder developing about 1 volt, it will show you that it is a question of voltage to break through the oxide layer. After tat, you have conductivity. In order to spot weld, scratch the surfaces hard with a rotating steel brush, after that you have about 1 sec. for the welding. Alu surfaces oxidise and thus the area in the vicinity of the contact gets smaller. This gives a rising current density at the contact spot. Current through a resistance gives cause to heating until the hole contact area burns up or melts down, if there is enough power delivered by the wires.
Peter Am 07.10.2016 22:05, schrieb andy pugh: > On 7 October 2016 at 20:55, Przemek Klosowski > <przemek.klosow...@gmail.com> wrote: >> If the alumina layer is thickened (e.g. by anodization), the aluminum >> objects will be isolated; > I will also note the apparent conductivity of my anodized > solder-sucker. But that is probably a think anodised layer, not one > intended for isolation. > --- Diese E-Mail wurde von Avast Antivirus-Software auf Viren geprüft. https://www.avast.com/antivirus ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, SlashDot.org! http://sdm.link/slashdot _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
