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-   -   Corrosion or CORROSION? (https://vansairforce.net/community/showthread.php?t=173394)

Vol88 07-16-2019 07:37 AM

Corrosion or CORROSION?
 
I am in the process of purchasing a 2008 RV10 QB kit that has been stored in an unheated hangar. Here in the Midwest, unheated buildings can generate a fair amount of condensation during our annual freeze/thaw cycles.

As a newbie, I have no criteria for normal weathering versus corrosion. So I'm looking for some educated opinions from those of you with some practical experience.

Some of the skins have areas of very slight pitting. Most are roughly the diameter of grains of salt. A few are small rashes, the diameter of dimes or quarters, that don't feel like they have any depth. Is this normal for unpainted aluminum? Will this get removed with the typical prep before paint?

Similarly, some of the white powder-coated metal fittings have slight rust stains on them. Again, is that normal, or will I end up replacing anything that shows any sign of rust?

Here is a link to photos of some of the areas. https://1drv.ms/u/s!ApsOqxQaP7rizEcF...H96L7?e=8miBnv

Thanks in advance for your thoughts.

Brantel 07-16-2019 07:49 AM

I know it looks temporary but those wires/tubes zip tied to the flight control mechanism makes me cringe for some reason.

The white stuff is typical of what happens when condensation from galvanized metal lands on alcad aluminum and dries. Many times this can be cleaned off with a swipe from a scotchbrite pad. Hard to tell how much damage has been done from a pic.

I would be concerned with the spars and stuff that has layers. If that stuff gets in between the layers, it can be impossible to get out.
The inside of the wing would be hard to clean up.

No way I would use those breakers and if that last pic is typical, this kit has issues. That one rivet shop head is almost corroded away.

The powder coated stuff looks typical considering the other parts. Those could be cleaned up and repainted.

I would pass, this thing already looks worse than some airplanes that are over 50 years old. It will take a bunch of work to clean this up!

Chris7 07-16-2019 08:34 AM

While the outside corrosion looks fairly minor (from what I can tell from the photos), the inside corrosion again isn?t bad but it?s basically impossible to stop now unless you pull it apart, clean it up with alumiprep and alodine then prime.

If you go to all that trouble then you may as well enjoy a build from scratch.

I?m sure at the right price for the right person the kit would be a good buy but it?s very hard to stop corrosion unless treated correctly.

Vol88 07-16-2019 12:06 PM

QB primier?
 
Thanks for the quick replies. The wings and fuse are QB and were primed. Does that ease concerns about what?s inside?

EXflyer 07-16-2019 04:44 PM

Corrosion
 
From what I see along with the other comment the wiring tied like it is makes looking into the whole build a little better. Another item is the corrosion on the electrical items, this it very bad and since its here where else is it in the system? Have an expert on RVs look at it before you buy as there could be some items that would make it not worth the chance. Bought a bad one years back turned out to be scrap metal.

Chris7 07-16-2019 04:58 PM

The primer should help yes, however even if primed a certain amount of care is still required to maintain any machine.

I would recommend getting a local A&P to do an inspection, a small cost which could save you either by not buying it or discovering the clean up won?t be that bad and you get a kit at the price you want.

Hope this helps

Vlad 07-16-2019 05:04 PM

Quote:

Originally Posted by Vol88 (Post 1359989)
Thanks for the quick replies. The wings and fuse are QB and were primed. Does that ease concerns about what?s inside?

Tom if price is right take it. Ditch all electric/wiring, treat bad spots, redo some riveting and you will be ahead of many of us. My powder coated parts are from 2006 and look exactly like yours with rusty edges.

Steve Melton 07-16-2019 05:06 PM

Quote:

Originally Posted by Vlad (Post 1360051)
Tom if price is right take it. Ditch all electric/wiring, treat bad spots, redo some riveting and you will be ahead of many of us. My powder coated parts are from 2006 and look exactly like yours with rusty edges.

ditto......

David Paule 07-16-2019 06:12 PM

For what it's worth, I'd pass on this kit for both the corrosion and the zip-tied stuff attached to the flight controls. Now they might just be temporarily tied on to hold them out of the way, that's hard to tell.

And it's good to know that the bulk of the plane is QB and factory primed. But for me, the corrosion is simply too much.

Dave

animal145 07-17-2019 06:23 AM

You?re not married to it. There are thousands of rv?s out there. If there is a doubt, there is no doubt.

Good luck on your buying adventure!

Alex

jcarne 07-17-2019 07:56 AM

I don't know about you guys, maybe someone else that knows more can comment, but on that interior picture it certainly does not look primed to me. I know Van's QB kits come with P60 which is pretty light but I'm just not seeing it.

fl-mike 07-17-2019 09:13 AM

I have a feeling that the storage area had fertilizer or something like that in proximity to the kit parts. The corrosion under the rivet heads and on the spar is concerning. That would be near impossible to correctly address. I would look for a kit in better condition, and add this example to the "primer wars" conversation as an example of "why I prime".

Chris7 07-17-2019 10:04 AM

Quote:

Originally Posted by jcarne (Post 1360187)
I don't know about you guys, maybe someone else that knows more can comment, but on that interior picture it certainly does not look primed to me. I know Van's QB kits come with P60 which is pretty light but I'm just not seeing it.

I would guess that?s the horizontal and not the wing. Also took a few looks for me to understand.

jcarne 07-17-2019 10:06 AM

Quote:

Originally Posted by Chris7 (Post 1360230)
I would guess that?s the horizontal and not the wing. Also took a few looks for me to understand.

Ah yes, I think your right. Now I see P60 on some of the fuselage parts.

Charles in SC 07-17-2019 12:57 PM

I looked at the pictures 3 times and the only primer I see is in the picture with the circuit breakers and on the on the elevator push tube. It looks like green something. My -7 QB kit is from 2006 I read somewhere that it should have primer but it did not. I would pass on this one. If you buy it you will be having to convince everyone that ever looks at it that it is ok and you will always have a question in your mind.

Vol88 07-17-2019 01:42 PM

Update
 
I had a chance to take another look yesterday, along with my A&P building partner who inspected everything visually, in detail. Here's some more information.

In spite of what the pictures look like, we saw no rivet heads with corrosion under them (probably light reflecting in the photos), nor did we see any bulging areas anywhere. There is light pitting distributed across the external surface of the parts. So the seller gave us some 1500 wet/dry paper and the pitting disappeared easily, leaving the Alclad intact.

Of more concern to my A&P friend were some dings and scratches that will need to be repaired, and that would give me the chance to get inside a few structures. When one door closes, another one opens...

The light spotty corrosion in one area of both QB wings may be because QB wings come without the bottom skins riveted in, and in this case the builder didn't prime before assembling the last skins.

The area that looks like rust at the bottom of the firewall in one of the photos cleaned up nicely with water and a rag.

I spoke with a person with expertise in light aircraft metallurgy and paint, and he suggested that light corrosion on QB assemblies might be the remnants from the salt air of the Phillipines, exacerbated by being cooped up in a hangar with no circulation for a couple of years, along with the summer heat around here. He also posited that the light corrosion I see is unlikely to progress much once the plane is in an environment with normal circulation and ventilation.

I thought the powder-coated parts were bad until my friend pointed out the torque tube one was attached to. It looked like someone had taunted a Doberman with it. And the Doberman might have been carrying a pipe wrench.

By the way, the zip ties several people have commented on are only keeping the wires from tangling or falling into the wing while it is stored. On the other hand, they'll all need to have new terminations on both ends.

Thanks for all of your observations and opinions. This is just the second time I've posted a question on VAF, but both times I've been impressed with how responsive and helpful my 21,000 or so new aviation friends are.

I hope to meet some more of you at the various RV soirees at KOSH.

Tom

Vol88 11-25-2020 11:54 AM

Update
 
To close the loop on this thread, I purchased this unfinished kit in August 2019. Many thanks to those who responded with opinions and expert advice. I admit I was swayed most by the responses from those - like Vlad - who could speak to the difference between unpainted aluminum and corroded aluminum. I most appreciated the time that Vic Syracuse graciously spent with me in between two of his presentations at AirVenture 2019, looking at closeups of pits, rivets and dings, and suggesting how to structure the purchase, given a brand-new, out-of-warranty engine.

Why close the loop now? Our hostís reminder about contributions reminded me that, if I hadn't been part of VAF, I would not have known to contact Vic, so I'm sending a small honorarium to DR in Vic's honor, over and above my annual contribution.

By the way, Iíve been through much of this kit in detail - including rebuilding a part of the tail cone - and Iíve seen virtually no corrosion on the unprimed Alclad faying surfaces. If Iím still living in the Midwest when I build my next plane, Iíll probably skip the primer on Alclad surfaces.

lr172 11-25-2020 12:20 PM

Quote:

Originally Posted by Vol88 (Post 1480326)
To close the loop on this thread, I purchased this unfinished kit in August 2019. Many thanks to those who responded with opinions and expert advice. I admit I was swayed most by the responses from those - like Vlad - who could speak to the difference between unpainted aluminum and corroded aluminum. I most appreciated the time that Vic Syracuse graciously spent with me in between two of his presentations at AirVenture 2019, looking at closeups of pits, rivets and dings, and suggesting how to structure the purchase, given a brand-new, out-of-warranty engine.

Why close the loop now? Our hostís reminder about contributions reminded me that, if I hadn't been part of VAF, I would not have known to contact Vic, so I'm sending a small honorarium to DR in Vic's honor, over and above my annual contribution.

By the way, Iíve been through much of this kit in detail - including rebuilding a part of the tail cone - and Iíve seen virtually no corrosion on the unprimed Alclad faying surfaces. If Iím still living in the Midwest when I build my next plane, Iíll probably skip the primer on Alclad surfaces.

Glad to hear it worked out. I also bought a previously started kit. I am in Schaumburg and finished my 10 last December. Feel free to reach out if you need help or want to see a finished example.

Larry

FlyinTiger 11-26-2020 03:51 AM

QB wash primer
 
For those concerned about not "seeing" the primer inside QB kits I too was a little concerned since they are advertised as having been primed. After calling Vans to chat they told me the primer is applied without the pigment so it is clear. Also as a "wash primer" it is not nearly as robust as those two part epoxy primer coats, but that as a result it is much lighter. A compromise of sorts...

I bought a -7 that was assembled with a QB fuse and wings so my research during that process was extensive. I'm glad the OP is happily working on his new project and will get another one of those kits sitting idle into the air.

Best of luck to all the builders this season!

Vol88 11-27-2020 07:18 AM

Thanks Larry. Iím the guy that took your fuse cradle, and appreciate it every time I work on the plane. I also saw your -10 at KDPA when you were starting your Phase 1.

There will be a fleet of 10s in the western suburbs in another year or two.


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