Rusty wing struts

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Rusty wing struts

Postby alan » Thu Jul 24, 2014 9:42 pm

Greetings all.

I have a recurring problem with the wing struts, jury struts, and landing gear bungee struts rusting. I have had them re-powder coated several years ago from a reputable powder coat specialist yet they started rusting again.

I plan to remove them soon, sand blast them myself, and paint them with epoxy primer/paint and clear coat. Is there anything I should be careful about while sand blasting these parts? Is it OK to sand blast or should I go with a media blast of some kind?

Any suggestions would be appreciated.

Alan
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Re: Rusty wing struts

Postby HS-JAT » Thu Jul 24, 2014 11:19 pm

On my last repaint I covered them (Jury Struts and clamps) completely with thin 1 inch leading edge tape. Hard to see, and hopefully extends the exposure to the elements.
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Re: Rusty wing struts

Postby alan » Tue Jul 29, 2014 6:36 pm

I was kind of hoping that Jak would chime in on this subject. Jak, you out there?

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Re: Rusty wing struts

Postby jak » Tue Jul 29, 2014 7:56 pm

I'm here mine were powder coated 5 yrs. ago still no rust but has been kept inside hanger except when flying. The one thing I have seen is when the parts are at the powder coaters they sand blast the parts and then handle them bare handed. this will induce rusting on freshly blasted metal from the acid in your skin. if you have it blasted again wear the rubber gloves to handle the parts until painted. Jak
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Re: Rusty wing struts

Postby alan » Tue Jul 29, 2014 11:50 pm

Thanks Jak. I have sand blasted and painted quite a few metal parts and will certainly not handle the freshly cleaned surfaces with my bare hands. I was mainly worried about the effects of the sand blasting itself on the thin tubing. All of the other parts I have worked on were substantially thicker. Since you said the powder coater blasted them when new, I'm not as worried. My blaster is just a hobby setup, not a really high pressure commercial machine.

I'm going to use an epoxy primer and white base coat clear coat. My Highlander is also always kept hangered except when flying or away from home. Here is a picture of the rust.

Thank you. :D

Alan
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Re: Rusty wing struts

Postby jak » Wed Jul 30, 2014 5:46 am

Alan with the blasting you want to stay back a little so as not to pit the metal so use a softer media than silica sand. JaK
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Re: Rusty wing struts

Postby alan » Wed Jul 30, 2014 10:12 am

Thank you Jak. I knew I could count on good advice from you. If the rain holds off I should get one strut blasted and painted today.

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Re: Rusty wing struts

Postby stede52 » Wed Jul 30, 2014 10:25 am

I helped another Highlander pilot with the same issue a couple years back and I don't know about your experience with removing powder coating by sandblasting but it had never worked all the well for me. The powder coating is just too tough! We ended up using Aircraft Paint stripper, scrappers and wire brushes. Its a pretty messy job but it worked very well as long as the stripper was left on the powder coating long enough for it to soften the paint. Once all the coating was removed we cleaned it, sanded it with 400 grit and cleaned it again and then had it powder coated. It's only been 1.5 years but so far so good. If I had to do this again and had access to a sandblaster I would use the Aircraft Paint stripper to soften the coating and then use the sandblaster. I think that would work well, messy! but I think it would work well.
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Re: Rusty wing struts

Postby alan » Mon Aug 04, 2014 5:53 pm

Yeah, the sandblaster didn't work so well. I cleaned off maybe 3 feet of one side of one leg of one strut assembly using an entire 50# bag of sand. Then I broke out my orbital sander and used about 12 80 grit sanding pads and cleaned almost all of the PC off of the rest of one leg of one strut assembly after three hours of hard work. I started with the idea of completely removing all the PC and moved towards removing only what was required to remove the associated rust and just rough up the rest. As I slowly progressed I discovered small patches of rust under completely unmarred PC every 2 to 3 inches. As I went over it the PC flaked off of the rusty area only and stubbornly stuck to the rest. Of course, the evidence of this was removed at the same time on that one leg. I then coated that leg with a rust converter and went home and took a shower. The next day, Saturday, I stopped at a hardware store and picked up some paint stripper hoping it would help some. It said it would remove epoxy so how about PC?. Hey, it actually worked, to a point. Thanks Steve. Here is a picture of a semi-cleaned patch on the other leg. You can see the rust patches on the foot long strip. Since then I have removed the PC on most of one side of the second leg of the first strut assembly and found these rust spots along the entire length.

Now comes the fun part. I was wondering about the structural integrity of these struts, especially because of the inside. While building our Highlander more than 8 years ago, I drilled a 1/8" hole in the top of each leg and squirted some oil inside to stop any rust. While rolling it around to coat the entire inside I found that the strut wasn't air tight. All the oil leaked out of the strut tubes at the bottom. Well, one of the tubes. I went ahead and sealed up that 1/8" hole with an epoxy coated rivet. If the outside, coated, areas are rusting under the PC, what is happening to the inside, uncoated areas of that one tube? I started thinking about just buying new parts, including the landing gear bungee strut pieces.

So, I've talked to Harry and Jak and they are making those pieces for me, bare metal, not PC. My wife wants a road trip, so here we go. A visit to Just Aircraft!

Alan
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Re: Rusty wing struts

Postby alan » Fri Aug 22, 2014 2:50 pm

Well, we did it. Went to the Just Aircraft factory and picked up our new parts.

New lift struts, jury struts and clamps, landing gear v-brace and bungee struts. It was a Friday so not everybody was there but talked to Harry for a couple minutes. Just as I was paying the bill in walked Troy. He knows that we're from down Texas way so he was curious as to why we were there. I told him of the rust problem and he wanted to look at the strut I brought along for that purpose.

Now here is the interesting part. After looking it over he said he wished I had brought both of the struts with me as he was willing to swap me my old struts for the new struts. Hey, says I. These struts are more than 8 years old and have a little more than 600 hours on them! Why would you do that!? He told me the powder coaters didn't do an adequate prep on these parts before coating and it was basicly Just Aircrafts' fault that they rusted. WOW! Now that is customer service!

So now I'm busy painting all these parts and locating new hardware to mount them. I will be shipping the remaining strut back to them next week. Once again I'm gonna say it. You can't beat Just Aircrafts' products and you sure can't beat their customer service. :D :D :D

Alan
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