Cleaning up landing gear- Help please

[piclr60]

Can anyone give me some help on how to properly knock the paint off the landing gear and get rid of a little bit of surface rust that is starting to appear on the gear. The paint has been chipped off and needs to be touched up.

1. Should I use scotch brite only or can I sand lightly?
2. I know I should not use certain chemicals on the gear. What should I use?
3. Recommendations for primer and paint.

Thanks

Brad

[T. C. Downey]

Is the gear removed?

[piclr60]

It is not removed. Want to clean it up without taking it off.

Thanks

[bagarre]

If a scotch brite pad will knock off the rust, do that and paint it.

if you use chemicals, make sure they are approved. but if you're going that far, I would pull them off and media blast them.

Mine are doing the same and you can see where there is paint over other issues. I'm so tempted to pull them to sand blast and magnaflux then for cracks and repaint them.

What's the opinion on some of the rust conversion paints out there?

[Hawkeyenfo]

I'm looking at the same type of light surface corrosion on my gear legs. It's been there for as long as I've owned it (7 years) with no real change but, I've been thinking about painting it. Post a few pics if you end up doing it

[KS170A]

I'm not sure what the proper terminology is, but Cessna either strongly discourages or prohibits use of chemical strippers on gear legs. The chemical reacts with the steel to create hydrogen embrittlement (search for that term among the forum and you'll find out a bit more). If you want to do the job right, remove the gear, bead-blast them, prime and paint. More threads about that will result from your search for hyd embrittlement.

Some years ago (circa 2005), I saw some security video footage of a Cessna Caravan that had been rolled out of a hangar. After the tug disconnected and backed away, one of the main gear legs broke - just sitting there! The leg was returned to Cessna for analysis...cause was determined to be hydrogen embrittlement. Makes the gear very brittle, such that any imperfection of the gear becomes a brittle stress point.

[piclr60]

Thanks for the comments. I would like to pull them off but it just won't be now. I don't have all the resources required and don't have the cash to have it done by someone else.

What about Naval jelly? I saw some specifically for steel. Any thoughts on if that will cause that brittle problem?

Brad

[T. C. Downey]

There are no chemical strippers on the market that will cause hydrogen embrittlement this requires heat and strong acid such as used in plating and can be eliminated by a 24 hour bake at 400 degrees.

http://en.wikipedia.org/wiki/Hydrogen_embrittlement

When installed, I'd simply get my little hand sander and sand with 320 or finer grit, until I have them smooth enough to repaint. using a good red iron oxide primer and a good quality paint.

[T. C. Downey]

What about Naval jelly? I saw some specifically for steel. Any thoughts on if that will cause that brittle problem?Brad

Naval jelly for steel is an acid that converts red rust to black iron oxide, you do not need to apply it in your case. simply sand smooth and repaint.

[GAHorn]

There are no chemical strippers on the market that will cause hydrogen embrittlement this requires heat and strong acid such as used in plating and can be eliminated by a 24 hour bake at 400 degrees.

http://en.wikipedia.org/wiki/Hydrogen_embrittlement

When installed, I'd simply get my little hand sander and sand with 320 or finer grit, until I have them smooth enough to repaint. using a good red iron oxide primer and a good quality paint.

FAA Advisory Circular 43-205 applies: ( http://www.faa.gov/documentLibrary/medi ... 43-205.pdf )
Quote: "(5) Cautions: Hydrogen Embrittlement.
(a) When high strength steels, some high strength aluminum, and some stainless
steels are exposed to acid paint removers, plating solutions, other acidic conditions (cleaners,
etc.) even some alkaline agents, cathodic reaction on the metal surface produces hydrogen, which
diffuses into the bulk metal, accumulating at grain boundaries that weaken the structure. If the
part is under a load or contains residual manufacturing stresses, sudden catastrophic failure can
occur and the part may no longer sustain internal and/or applied stresses. Hydrogen
embrittlement"

Cessna also warns against using chemical strippers on landing gear mainsprings .
Media blasting (plastic bead or glass bead) is one good method to remove paint.
The methods of re-treating the the landing gear (shot peening/painting/etc) are in the MX Library.

[c170b53]

Scotchbrite would be a very acceptable method to remove surface rust spots in situ. If you making faces at the rust areas, you might as well eyeball check the attach bolts and the gear wedges while you're at it.

[piclr60]

Thanks for all the info. I really appreciate all the knowledge

Brad

[n2582d]

RemovAll paint stripper

[piclr60]

Finally have some pictures to show before and after. I used the info from all the posts. I used a wire brush and some light sandpaper. Then oxide primer and some tractor paint. It took a long time to fully dry but it came out great. Then I got some 3m abrasion tape from a friend ( at $350 a roll).

Thanks for the help and info.

[blueldr]

I don't believe you can do them any damace by hand sanding.
Pulling them off is way too much work just to clean them up for repainting.