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Bad metals to use with aluminum?
Posted: Tue Apr 27, 2004 9:32 am
by Yoshida
I'm going to be making an aluminum helm for a youth combatant and was wondering if there were certain metals that may react poorly when attached to it (eg, copper or brass rivets, or other ferrous or non ferrous pieces of trim)?
Posted: Tue Apr 27, 2004 11:26 am
by ]I)ongal
A quick glance at a galvanic chart shows that you'll be worst off with platimum
... Really, Al. is crappy with all metals. It will sacrifice for all metals except Magnesium, Beryllium, and Zinc. The safest would be a 400 series stainless. If you really want to go with contrasting metals, you could clearcoat the al. where it will contact the trim, just live with a little galvanic corrosion, or use nearly anything OTHER than Aluminum.
Posted: Tue Apr 27, 2004 12:20 pm
by Sean Powell
]I)onigal,
I've been looking for a good material galvanic reaction chart for a while. Something that has both alloys and base metals (most have only base metals). Any chance you know where one is online?
Sean
Posted: Tue Apr 27, 2004 1:38 pm
by ]I)ongal
Sorry, I was looking in Marks' Standard Handbook for Mechanical Engineers.[/u]
Posted: Tue Apr 27, 2004 10:44 pm
by Gaston de Vieuxchamps
Brass rivets seem to be the worst.
You are usually fine though unless your armour stays sweaty and wet for a long time.
I always polish the alluminum before putting in brass rivets and try to use a little car wax on it too which also helps.
In any event, it usaully takes years before you have a problem...
Posted: Wed Apr 28, 2004 10:57 am
by Alexander of Derlington
Yoshida
I would make a thin steel one instead. I have helped make one Al tab top great helm (never again) and it was way harder than if we had used 18/20 gauge steel.
Rgds
Alex