Quickest way to remove oxidation from antenna elements

[K8WBL]

Recently acquired a Hygain TH6DXX yagi and am reconditioning it to re-install it.  Has a fair amount of rust, am replacing hardware with SS stuff.  However I would like an easy way to remove the oxidation from the elements.  I generally use steel wool on smal projects...any ideas?

73, Tim K8WBL

[Jim, W5JO]

Steel wool is not suggested on Aluminum and there is no easy way to remove corrosion.  So what I suggest is use scotchbrite pads then vinegar on them. Once they are clean, then use noloax on the joints ,and if you are in a corrosive environment, cover the entire antenna. 

Aluminum is a compound and covered by a substance that prevents it from corroding.  If you scratch it much you will remove it, and it will loose the ability to resist the corrosion.

[W2PHL]

If you're not painting or welding the aluminum, I wouldn't worry about using steel wool. A soapy SOS pad will make it shine like new.

[ka3zlr]

Good old Elbow grease and a Scratch Pad, after that either by piece or when assembled spray with a clear coat.

73
Jack.

[K1JJ]

Tim,

New aluminum develops its own oxidized covering from the weather - that's its protection. By cleaning it off, you will simply make the aluminum start over and make a new coating. Aluminum doesn't stay shiny for more than a few weeks in the weather anyway, so why bother?

As already suggested, you could clean the joints and coat with No-Ox or equivalent, but after that, I would let it go as is.
It's up in the air and hard to see anyway.

BTW, I spent hours cleaning up an old Gruman aluminum canoe last year. It shined like a mirror.   I had compounded and waxed the heck outa it.  After a few weeks (or was it days?) in the weather it was back to its normal dull aluminum look as normal.



If you still want to polish it, here's some articles on the subject:

http://www.ehow.com/how_4548758_remove-aluminum-oxidation.html

T

[K8WBL]

Thanks, that is good info, I think I will just clean the joints and replace the hardware with SS bolts and perhaps try the SOS pad or scratch pad on the hygain element to boom clam shells, some of the bolts rusted pretty badly and I broke several of them getting it apart.

Tim

[Ed-VA3ES]

The BN86 balun that comes with the Hygain TH(X) series is useless. It's a voltage balun, and subject to varying balance depending on SWR.  I replaced mine on my TH3 with a RadioWorks,  Y1-5K current yagi balun, designed for yagis.

http://www.radioworks.com/cy1-5k.html

Works exceptionally well.  Excellent balance and is transparent to the yagi.

Caution, don't run more than about 500 W of AM through it, though it will handle about 5KW PEP. 

[N3DRB The Derb]

a dremel with heavy duty cutoff wheels is a much better way to deal with rusted bolts and nuts. just cut em out by sections and dispose. Just clean the joints and cut out rusted anything and replace with S.S. hardware.

Aluminum recoats itself the millisecond it's exposed to new oxygen hitting it's surface. The only way to prevent this is to anodize it, which also makes it electrically non conductive.

Aluminum has about 48% the conductivity of pure copper depending on the alloy. 

[n2bc]

As was mentioned steel wool (SOS pad) is not a good idea. Bits of the steel can get imbedded in the aluminum & you get iron oxide.

For cleaning joints prior to assembly I use wet/dry abrasive paper.  Plenty of water to wash the aluminum oxide away and keep the abrasive from loading up..  It's fast and messy!  For inner surfaces I use a bronze plumbing brush.  A good coat of NoAlOx on both surfaces right away will keep it conductove for years (also messy).

Carefully check inner surfaces for mud wasp 'houses' too, flush them away with water.

I've done this a few times with a 35 year old tribander and a 35 year old Universal tower, both doing FB!

73, Bill  N2BC

[K8WBL]

Thanks, those are good ideas -

73, Tim K8WBL

[WBear2GCR]

A plain, non soap loaded scotchbrite material + baking soda seems to work very well on aluminum. Test first, of course.

               _-_-bear


EDIT: water... use water with that - probably self evident, but not really...

[Rob K2CU]

IF your using SS nuts and bolts, be careful not to over torque them. SS is not as strong as Cad steel bolts nad esily gets deformed. I had installed a TH6DXX some 30 years ago with all SS bolts. When we took it down for overhaul a few years ago, all the bolts were shiney, but almost half sheared off when trying to loosen them. They had all been ovwer torqued.

[W3SLK]

Rob said:

IF your using SS nuts and bolts, be careful not to over torque them. SS is not as strong as Cad steel bolts nad esily gets deformed. I had installed a TH6DXX some 30 years ago with all SS bolts. When we took it down for overhaul a few years ago, all the bolts were shiney, but almost half sheared off when trying to loosen them. They had all been ovwer torqued.

Hmmmm, must have been cheap stainless. Usually, stainless steel nuts and bolts have a tendancy to gaul rather than flex. Any stainless hardware I use is liberally coated with 'nickel' Never-Seize. You may be the one taking it apart.

[K1JJ]

Yes, SS is the way to go.

I'm in the process of taking down and rebuilding many of my homebrew Yagis right now. There's some that have been up for close to 10 years now with steel torque arms and associated SS hardware. There is a LOT of SS U-bolts and SS nuts/bolts used.

It's a pleasure to remove the SS U-bolts. They are all like brand new and can be reused. The nuts and bolts turn with little effort. I always use those nuts with the nylon inserts to lock them on, or SS lockwashers.

I also have a number of standard steel u-bolts and hardware that I cheaped out on. Those almost always break off when removed or have to be sawed off, they get so rusted. Even the galvanized stuff has a limited life once the threads get scored.

It may cost double the price to do, but SS is the way to go, especially if the hardware is in direct contact with the tower legs. Rust can easily contaminate a good tower galavanizing and work its way down the tower.

I've climbed a number of other hams' towers and am often amazed at the beautiful aluminum but the absolute mess of rusted hardware I see. Always use SS hardware on towers and antennas!


BTW, yes, SS is slightly weaker than standard steel, so I simply use one size larger for the job - instead of 3/8" standard, I'll use 7/16" SS or whatever is available slightly larger, etc.

T