Rust on Gear Leg

[Bill Boyd]

It was only present on one of the two legs

[Bill Boyd]

As widespread as this is, and appearing on never-flown gear, I wonder if there is a process problem becoming apparent.

It certainly isn't reassuring.

[JonJay]

Originally Posted by Bill Boyd

It was only present on one of the two legs

Actually, this doesn't look like corrosion. I have seen this before whereby the powder coating had adhesion issues due to contamination during the prep. I had a few spots on my motor mount similar to this. There was no rust just poor adhesion. Of course, left untreated it certainly will start to oxidize and corrode.

[n82rb]

my family owns a powder coating operation, that looks like typical case of letting the parts set to long between prep to powder. it is very important to get the parts straight from abrasive blast, or chem prep straight to the powder booth. here in florida, if we blast parts on second shift and wait for first shift to shoot them that happens because of the high humidity and salt content of the air here. it sometimes takes a while, but he oxidation process starts as soon as its prepped, and if moisture and oxidation is present when the powder goes on that WILL happen.

bob burns
RV-4 N82RB

[Bill Boyd]

Then it was certainly "left untreated." (I had the kit for 3 years before getting to this stage, and it had been in the possession of others for maybe 5 more). When I sanded it down, there was certainly Fe2O3 in evidence. Not much, but the sandpaper was definitely brown.

Whatever the final result, it would be interesting to see if the root cause is the same and can be identified/remedied. Meanwhile, inspections are a good idea as part of the annual. Fairings are not hard to pull.

[Tommy123]

Strip that bad powder coat job off and use rattle can Porsche-15. Did that with my Mooney nose gear.

[Boyd Birchler]

I spent 34 years in the metal coatings removal business. Most likely cause is improper application of the powder coating. Incomplete precleaning/prep,insufficient thickness applied or underbake.

In the area where the coating is bubbled you must remove down to the bare steel or you will geet filiform corrosion under the new coating.

[Bill Boyd]

Now I guess we wait for the factory to weigh in on this.

It's like waiting for the replacement part to do the -10 engine mount SB. Apparently there's a shortage of those steel plates. Maybe they're checking the powder coat twice before they let them out the door

[snoopyflys]

take to a convenient place to have them re-powder coated as the preferred option as it would hold up better to abrasion caused by the gear fairings. Second option is to strip and repaint with a quality primer and paint. No mention of being concerned about my particular lot being powder coating defective. So, basically, I am on my own.

Quick response to my email last night. The answer is not unexpected and kinda what I expected and aligns with then responses to my post here (Thank ya'll for taking the time to respond).

So, assuming I go the re-powder coating route, I get to figure out how to go about lifting the airplane with wings and engine, etc installed where it is supported enough to not cause any damage to the plane or me. I have seen/heard/read there are jacks that can be used at the tie down points. Is this the best solution for lifting the whole plane high enough to get the gear out of the main gear weldments?

By the way, I found the same "Rust Freckling" on my elevator horns. I guess my best option there is to strip/treat/prime and paint as disassembling the elevator horns from the elevators would do more harm than good.

Man, if I knew what I know now back in 2010, I would have had all of the powder coated parts redone.

[Larry DeCamp]

I have 1999 RV4 kit with good powder coated parts. BUT, Acetone will take it off.
Epoxy and 2K urethane are not affected as we all know.
For the experts:
1- Should good powdercoat be immune to Acetone ?
2- I wrapped my -3 gear with glass and West 105, to isolate it for Carbon Fiber stiffeners and fairings. Any concerns about West 105 endurance on clean (chemically) gear leggs ?