I'm patching my roof which is slate with lead flashing and copper nails. If I use caravan aluminium for flashing is it gong to rot, (by the battery effect) when it touches the copper or lead? I know some metals are incompatible. [g]
aluminium flashing rot?
Nov 10, 2010
10 Replies
A proper chemist may come along and say different, but my experience suggests it's not likely to be a problem, I suspect because you won't get a good electrical connection because of the protective oxide.
I would say the reverse.
Lethal.
But I am not sure.
If there is lead there to start with why not use more lead?
lethal? how come?
I have lots of caravan aluminium for free, lead is very expensive.
[g]
Sell the ali to buy the lead.
lethal for the aluminium.
so is doing it again in two years.
Look up the galvanic series on Wikipedia. The further apart the two metals are, the more reactive they are with one another.
It needs a suitable electrolyte. Rainwater would be slightly acidic and would support corrosion, but not significantly if the metals aren't immersed in standing water.
Probably. If you are within 20 miles of the coast the salt will get at it. Or road salt if you are near a fast busy road that is regulary treated.
Google will find you sites that say how compatible Ali is with lead or copper. But Ali is pretty reactive. I like the suggestion to sell the ali to but the lead. B-)
Thanks, I was right to worry, Lead it will be. [g]
any salt alone is enough to corrode al even when not in contact with any other metal.
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