I'm glad you brought up this topic, Bob. Every time I enounter this powdery
effect on aluminum, I think "the RCM'ers would know what causes this, and
what to do about it", but then I forget.

Since Mike H said not to use any sort of base on aluminum, I thought I'd
look for some examples of common compounds will cause the erosion reaction.

Some soaps, ammonia, lime and possibly some other products like lye. I
recall seeing cautions on some household products stating; not for use on
aluminum, or do not use on aluminum.

I'm also interested in knowing what to do about areas that are affected,
such as removing any active contamination and stopping the erosion.

--
WB
..........
metalworking projects
www.kwagmire.com/metal_proj.html


"Bob AZ" wrote in message
...
I am cleaning up the Water pot on my Baldor Grinder. The grinder and
the Water Pot had never been cleaned up at all in its 50 years of use.
I had to sandblast a lot of the grinder itself but the Water Pot is
aluminum and not as substantial as the grinder itself.

I have the outside of the Water Pot cleaned up nicely but the inside
seems to be leaching out, shall we say, some white powdery stuff that
easily wipes off but more come back in 24 hours or less.

Is there perhaps some acid or caustic liquid that will help? Or should
I simply wire brush until I get the inside down to the base metal
which I think is aluminum?

Thanks for the assistance.
Bob AZ