On Apr 29, 10:37*am, Michael Coslo wrote:
Jim Lux wrote:
lagagnon wrote:
I am about to refurbish an old Hy-Gain TH3-Mk3 Thunderbird tri-band
yagi. This yagi has been used in a coastal environment and thus the
aluminum is slightly pitted and most of the connecting hardware needs
replacing.

I figure steel wool would work fine for the aluminum tubing,

Avoid steel wool. Inevitably, it will leave little iron/steel fibers
behind, which will rust/corrode/react with the aluminum.

* * * * Hi Jim,

I keep hearing about steel wool rusting in/corroding Aluminum, but does
anyone have actual evidence? I've been looking on the web, and although
apparently using steel wool on AL will cause warts, bad breath, and the
downfall of the free world, all I've found is admonitions not to use it.
Maybe I'll try an experiment - I have some old antenna tubing.

There's just something a little strange about this. For the steel
particles to corrode the AL, they would have to detach, (easy enough)
settle into pores in the Aluminum at sizes small enough to do that,
(hmmm, those are pretty tiny steel particles) or have some odd property
of sticking to the AL despite cleaning. Then I guess it's a race between
rust and galvanic corrosion?

Use synthetic scrubbies (3M ScotchBrite) instead.

Bronze or stainless steel wool might be a good material to use. Boaters
use it on aluminum.

* * * * - 73 de Mike N3LI -

When you scour with the steel wool it will cut into the soft Al and
break off. You wont know about it until it starts to rust. Some
aluminum alloys dont seem to have as much of a problem with this but
others do. Ive had it happen to me, warned someone who still tried it
and had no problem.

Jimmie

I keep hearing about steel wool rusting in/corroding Aluminum, but does
anyone have actual evidence?


Yeah, the mast on my sailboat as done by a previous owner of the boat.
It has some serious cosmetic corrosion and small pitting (but didn't
effect the mast's functionality) where the PO used steel wool to
remove some boat adhesive he accidently got on the mast. There were
small pits in that area. This is not as serious as aluminun to
stainless steel hardware bimetalic corrosion. SOP for a boat mast is
to used threaded bolts, not self tapping screws and to tap the hole.
Then we put in some version of Loctite (don't remember which one there
are many varieties of Loctite) designed for the purpose and sold at
boating stores among many other places. That minimized the bimetalic
corrosion effect. I never had any problems with the masts on my
sailboat after I enlarged the corroded holes a size larger and then
tapped them and put the SS machine screws in. Using anything other
than 316 SS screws is inviting disaster on a boat. Hardware starts to
fall off boats.

BTW my small sailboat sank last year, but that had nothing to do with
corrosion. My larger boat was donated to the Sea Scouts and I'm out
of sailing now. Wife (and crew) has had arthritis and had a triple
bypass a years ago. I just can't send her up the mast anymore :-).

Jon W3JT