intergrandular corrosion of wing spar

[ChrisH]

My A&P has dignosed this condition on my 1964 (Piper)PA28-140. Has
anyone dealt with this? Can the wings be repaired or rebuilt? Is there
a good source for spare wings? I'm in North Carolina.
Thanks,

Chris Hight

N6414W
JQF

[kage]

It will be far less expensive to purchase a set of used servicable wings,
than to re-build yours. Subscribe to Trade-A-Plane:

http://www.trade-a-plane.com/index.shtml

Karl


"ChrisH" > wrote in message
oups.com...
> My A&P has dignosed this condition on my 1964 (Piper)PA28-140. Has
> anyone dealt with this? Can the wings be repaired or rebuilt? Is there
> a good source for spare wings? I'm in North Carolina.
> Thanks,
>
> Chris Hight
>
> N6414W
> JQF
>

[Nathan Young]

On 15 Jan 2005 14:24:53 -0800, "ChrisH" > wrote:

>My A&P has dignosed this condition on my 1964 (Piper)PA28-140. Has
>anyone dealt with this? Can the wings be repaired or rebuilt? Is there
>a good source for spare wings? I'm in North Carolina.
>Thanks,

What does intergrandular corrosion mean? Sounds like a medical
condition.

You should check with Wentworth Aircraft on spare wings. I have also
seen them on eBay.

-Nathan

[jls]

"Nathan Young" > wrote in message
...
> On 15 Jan 2005 14:24:53 -0800, "ChrisH" > wrote:
>
> >My A&P has dignosed this condition on my 1964 (Piper)PA28-140. Has
> >anyone dealt with this? Can the wings be repaired or rebuilt? Is there
> >a good source for spare wings? I'm in North Carolina.
> >Thanks,
>
> What does intergrandular corrosion mean? Sounds like a medical
> condition.
>
> You should check with Wentworth Aircraft on spare wings. I have also
> seen them on eBay.
>
> -Nathan
>

It's some pretty bad stuff. But it's 'intergranular.' No 'd' in it if
you want to google and read about it, it means that the corrosion involves
the grain boundaries of the aluminum alloy.

[Orval Fairbairn]

In article >,
" jls" > wrote:

> "Nathan Young" > wrote in message
> ...
> > On 15 Jan 2005 14:24:53 -0800, "ChrisH" > wrote:
> >
> > >My A&P has dignosed this condition on my 1964 (Piper)PA28-140. Has
> > >anyone dealt with this? Can the wings be repaired or rebuilt? Is there
> > >a good source for spare wings? I'm in North Carolina.
> > >Thanks,
> >
> > What does intergrandular corrosion mean? Sounds like a medical
> > condition.
> >
> > You should check with Wentworth Aircraft on spare wings. I have also
> > seen them on eBay.
> >
> > -Nathan
> >
>
> It's some pretty bad stuff. But it's 'intergranular.' No 'd' in it if
> you want to google and read about it, it means that the corrosion involves
> the grain boundaries of the aluminum alloy.


In worst case, you can crumble the aluminum with your bare fingers. The
most prone alloys are 7075 and (non-clad) 2024, due to their high
magnesium content. Moisture is the big enemy here, as it promouet
surface corrosion, which then attacks the grain structure of the
aluminum alloy.

The only solution is to replace the offending part.

[[email protected]]

ChrisH wrote:
> My A&P has dignosed this condition on my 1964 (Piper)PA28-140. Has
> anyone dealt with this? Can the wings be repaired or rebuilt? Is
there
> a good source for spare wings? I'm in North Carolina.
> Thanks,
>
> Chris Hight
>
> N6414W
> JQF

Their has been discussion about this on the Cardinal owner's group.
Apparently intergranular corrosion is actually caused by improper heat
treating of the part, which leaves it vulnerable to the corrosion
causing elements of moisture, etc. As has been pointed out, it is very
bad stuff as you cannot remove the corrosion and treat it if you catch
it early enough, as you can with Galvanic corrosion. The offending
parts must be replaced.

Bruce Cunningham
N30464 C177A

[Jon A.]

On 16 Jan 2005 12:03:42 -0800, wrote:

>
>ChrisH wrote:
>> My A&P has dignosed this condition on my 1964 (Piper)PA28-140. Has
>> anyone dealt with this? Can the wings be repaired or rebuilt? Is
>there
>> a good source for spare wings? I'm in North Carolina.
>> Thanks,
>>
>> Chris Hight
>>
>> N6414W
>> JQF
>
>Their has been discussion about this on the Cardinal owner's group.
>Apparently intergranular corrosion is actually caused by improper heat
>treating of the part, which leaves it vulnerable to the corrosion
>causing elements of moisture, etc. As has been pointed out, it is very
>bad stuff as you cannot remove the corrosion and treat it if you catch
>it early enough, as you can with Galvanic corrosion. The offending
>parts must be replaced.

Correct, it is in the manufacturing process.

[Robert M. Gary]

Does stuff like Corrosion X help prevent it?

[Jay Honeck]

> My A&P has dignosed this condition on my 1964 (Piper)PA28-140. Has
> anyone dealt with this? Can the wings be repaired or rebuilt? Is there
> a good source for spare wings? I'm in North Carolina.

A good friend of mine went through this exact problem with his 140. It is
not a good deal.

As others have pointed out, it is a non-repairable problem -- the wing spars
cannot be replaced economically. The only fix is to replace the wings, and
that is not cheap.

My friend's experience was a long series of nightmarish problems with
unforeseen consequences (One example: The first set of replacement wings he
found were crushed in shipping, and the shippers refused to pay to replace
them.), and the plane was "down" for well over a year.

You've really only got two choices: Part the plane out, or fix it. If you
want to fix it, call Wentworth, bite the bullet, and pay their ridiculous
price for serviceable wings. Have them ship the wings directly to your A&P,
and get it done as quickly as possible. Having watched this ordeal from
afar, it seems that attempts to find alternate sources for wings will end up
taking far longer, and cost far more, than you expect, and the aggravation
factor is not to be underestimated.

Good luck.
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

[Stealth Pilot]

On 16 Jan 2005 18:07:39 -0800, "Robert M. Gary" >
wrote:

>Does stuff like Corrosion X help prevent it?

no
because the corrosion is actually occuring between the metallic
components of the alloy deep below the surface.
in 2024 the copper and aluminium can react together.

anticorrosives applied to the surface cant get near it so they are
ineffective.

dont feel too special even boeing airliners have had expensive spar
repairs because of it. piper cherokee flap ribs are quite susceptible
to it.

if you ever take a little tap hammer and tap along a spar web surface
and hear the sound change for no apparent reason you've probably found
intergranular corrosion. (thats how the boeing corrosion was found)

Stealth Pilot

[ChrisH]

HI and Thanks,

to everyone who has answered. Quite an education I must say. It was
quite a disappointment to find the plane I bought 15 months ago, has
such a severe problem.

I never thought that those full stall landings might be what was
keeping the wings on.

Here is the best photograph I have seen of intergranular corrosion on
Fig2

http://www.asnt.org/publications/materialseval/basics/oct03basics/oct03basicsfig1.htm#fig2

Mine looks worse.

The good news is that everything else (and everywhere else) looked good
through the annual inspection. We have a lead on two wings and my A&P
should be calling today.

I've been on the Usenet since 1987 and I continue to be amazed at the
expertise and the willingness of it's members to share information and
experience .

Chris Hight
N6414W
JQF
Davidson, NC

[Jay Honeck]

> to everyone who has answered. Quite an education I must say. It was
> quite a disappointment to find the plane I bought 15 months ago, has
> such a severe problem.

Intergranular corrosion is something that should be carefully checked
for at every annual -- and should absolutely have been caught in any
pre-buy inspection.

You may have recourse against the shop that did your pre-buy, Chris.
You're looking at spending thousands of dollars here, and any competent
mechanic certainly should have seen this stuff just 15 months ago --
especially if it's as bad as you say it is.

Honestly, I simply don't understand some of the goofy stuff that A&Ps
miss. Cherokees are simple aircraft, and are darned near bulletproof
-- but they do have a few known problems that every competent mechanic
should know to check.

Intergranular corrosion, while not rampant in the fleet, IS a known
(and very serious) problem in older Cherokee wing spars, and should be
checked carefully. It's a definite deal-stopper if found.

Here are a few other less-critical Cherokee issues to look for, while
we're at it:

1. Doors that are "sprung" and don't fit quite right. (Seen most often
in trainers.)
2. Corroded heater control flapper valves.
3. Leaky fresh air vents.
4. Bouncy/inaccurate ammeters.
5. Sticky elevator trim, both electric and manual.
6. Cracked bow-tie yokes (found on older Cherokees only).

All of these are well known to any good Cherokee mechanic, are commonly
looked for at annual, and can be easily addressed.

Good luck.
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

[Chicken]

I helped assemble an Alon A2A which had been shipped over from England about
2 years ago. Everything looked fine. A recent AD required a center section
inspection. During this AD I found a couple of suspicious bulges in the
lower spar cap. Upon probing them intergranular corrosion that had
penetrated the spar cap and progressed to exfoliation was discovered.

The elapsed time from assembly from the shipping container when everything
looked fine, to discovery of the corrosion was 1-1/2 years.

So this corrosion had been festering in the internal grain structure for
nearly 40 years before it came to the surface. When it did appear, the spar
cap had already been penetrated through and through.

The plane was beyond economical repair.

Cheers:

Paul
NC2273H

[Aaron Coolidge]

Jay Honeck > wrote:
: A good friend of mine went through this exact problem with his 140. It is
: not a good deal.
: As others have pointed out, it is a non-repairable problem -- the wing spars
: cannot be replaced economically. The only fix is to replace the wings, and
: that is not cheap.
: My friend's experience was a long series of nightmarish problems with
: unforeseen consequences (One example: The first set of replacement wings he
: found were crushed in shipping, and the shippers refused to pay to replace
: them.), and the plane was "down" for well over a year.
: You've really only got two choices: Part the plane out, or fix it. If you
: want to fix it, call Wentworth, bite the bullet, and pay their ridiculous
: price for serviceable wings. Have them ship the wings directly to your A&P,
: and get it done as quickly as possible. Having watched this ordeal from
: afar, it seems that attempts to find alternate sources for wings will end up
: taking far longer, and cost far more, than you expect, and the aggravation
: factor is not to be underestimated.
: Good luck.

I will second what Jay said. I also have a friend who went through this. He
bought replacement wings from Wentworth. The second set were servicable.
The A&P keeps the old wings for show & tell: you could flake pieces off the
wingspar. It "only" took about 3 months for this guy's plane to get fixed.

Wentworth and the other salvage companies probably have a goodly supply of
easily repairable wings now! You can check google for aircraft salvage yards,
there are a few around. I think there's one in the Carolinas.
--
Aaron C.

[[email protected]]

Aaron Coolidge > wrote:
: easily repairable wings now! You can check google for aircraft salvage yards,
: there are a few around. I think there's one in the Carolinas.
: --
: Aaron C.

I've gotten a bunch of small things from US Air Salvage in Johnson City, TN.
There's an airport about 1/2 mile from them and they'll come out and pick you up.
They've been fair, but like any junkyard (aircraft or not), haggling is a must and
"stealer-deals" are hard to find. We bought a baggage floor out of a Cherokee 180 to
install in our 140/180. Pretty cool watching them take out a huge gas-powered
circular saw and cut a 3'x4'x6" chunk out of the fuselage of a plane. Even cooler was
watching us load the chunk into the aircraft it was going to be installed in and fly
home. A topological problem, to say the least.

-Cory


************************************************** ***********************
* Cory Papenfuss *
* Electrical Engineering candidate Ph.D. graduate student *
* Virginia Polytechnic Institute and State University *
************************************************** ***********************

[Jon A.]

On Mon, 17 Jan 2005 04:16:59 GMT, "Jay Honeck"
> wrote:

>> My A&P has dignosed this condition on my 1964 (Piper)PA28-140. Has
>> anyone dealt with this? Can the wings be repaired or rebuilt? Is there
>> a good source for spare wings? I'm in North Carolina.
>
>A good friend of mine went through this exact problem with his 140. It is
>not a good deal.
>
>As others have pointed out, it is a non-repairable problem -- the wing spars
>cannot be replaced economically. The only fix is to replace the wings, and
>that is not cheap.
>
>My friend's experience was a long series of nightmarish problems with
>unforeseen consequences (One example: The first set of replacement wings he
>found were crushed in shipping, and the shippers refused to pay to replace
>them.), and the plane was "down" for well over a year.

Scumbags! Name the shipper for us all!

[Jon A.]

On Mon, 17 Jan 2005 14:28:36 -0800, "Chicken" >
wrote:

>I helped assemble an Alon A2A which had been shipped over from England about
>2 years ago. Everything looked fine. A recent AD required a center section
>inspection. During this AD I found a couple of suspicious bulges in the
>lower spar cap. Upon probing them intergranular corrosion that had
>penetrated the spar cap and progressed to exfoliation was discovered.
>
>The elapsed time from assembly from the shipping container when everything
>looked fine, to discovery of the corrosion was 1-1/2 years.
>
>So this corrosion had been festering in the internal grain structure for
>nearly 40 years before it came to the surface. When it did appear, the spar
>cap had already been penetrated through and through.
>
>The plane was beyond economical repair.
>
>Cheers:

Unless they paid too much for it, or it was really a dog, center
sections can be had new for about $8K and used, about half that.
Unfortunately even parts aren't worth much to the owners who mostly
fail to maintain these birds well and up to standards. Sounds like a
good project for someone, I hope you guys didn't give it away.
>
>Paul
>NC2273H
>
>

[Jay Honeck]

>>My friend's experience was a long series of nightmarish problems with
>>unforeseen consequences (One example: The first set of replacement wings
>>he
>>found were crushed in shipping, and the shippers refused to pay to replace
>>them.), and the plane was "down" for well over a year.
>
> Scumbags! Name the shipper for us all!

Good idea. I'll ask my friend when he returns from vacation...
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

[Brian Sponcil]

Williams Airmotive in IN (Fort Wayne?) will rebuild your wings with new
spars for $2000/wing. I think that's about $1000/wing cheaper than you'll
find replacement wings at Wentworth. FWIW they rebuilt my 140's wings and I
was pleased with the results.


-Brian
N33431

"ChrisH" > wrote in message
oups.com...
> My A&P has dignosed this condition on my 1964 (Piper)PA28-140. Has
> anyone dealt with this? Can the wings be repaired or rebuilt? Is there
> a good source for spare wings? I'm in North Carolina.
> Thanks,
>
> Chris Hight
>
> N6414W
> JQF
>

[ChrisH]

Thanks Brian,

I just gave them a call. Around $7000 for rebuilding both, but that
means I won't have to paint them. They said the spars themselves are
$2000-2500 apiece. So how long ago were yours done (that the price was
so much higher?

I would feel better about knowing the condition as opposed to buying
used.

Chris

[Jay Honeck]

> -Brian
> N33431

Hey -- you're supposed to be on vacation! Whaddya doing here?

(Typical computer geek -- goes all the way from Iowa to California to escape
the cold, and ends up sitting around pecking away on his laptop... ;-)

So who *were* those scumbag shippers that ripped you off, anyway?
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"