"Roy Smith" wrote in message
...
I've got an idea for mounting a folding extension table off the back of
my table saw which starts with bolting an aluminum angle to the cast
iron top. Do I need to worry about electrolysis between the aluminum
and the cast iron?

I don't think so. First, for galvanic corrosion to take place, there has to
be the prescence of an electrolyte, usually water. Second, there's not a
large potential difference between cast iron and aluminum alloys. Even if
it did happen somehow, since aluminum is less noble than cast iron, the
aluminum (aluminium for our friends across the pond) angle would be the
anode and would sacrafice itself, so the table saw top would be protected.

todd