Treat minor filiform corrosion

For the corrosion issue, clean and prep per AC43.13. Last I looked, all the steps are in there. As long as there are no popped rivets or bulging seams, I would fix what is shown in the picture and keep flying. If that is all there is on a 40 year old flying beer can, you are far ahead of the game.

For the prop blade repair, it has to be filed (not filled) to remove the stress risers from the blade, while not changing the airfoil shape. Maybe an owner can do it, maybe not. I have seen poor workmanship on props and it costs more to fix. Go get an old U/S blade and practice before attempting for real. That is how I learned. Also read up on the standards for this kind of work. Good old Ac43.13 again!
 
GlennAB1 said:
Come back when you understand that abrasives abrade and a metal brush is an abrasive when it removes material.

We purchase wire brushes from Grainger, maybe you should correct them...

Abrasive Wire Brushes:

https://www.grainger.com/category/ecatalog/N-1z0dyod
Click to expand...
Granger can call them any thing they want, but until you understand the nobility of metals and the Brinell hardness you'll never understand why they are called platers brushes.

do you know why the chrome platers use them?
 
GlennAB1 said:
Produce that manufacturer's contrary data you are refering to.

My experience is that manufacturer's data often mirrors 43.13.
Click to expand...
Show me the data you speak of in the Cessna 100 service manual, or the Piper maintenance manual.
 
ircphoenix said:
You know Glenn is going to have a problem with anything you say.
Click to expand...

Actually I have the problem with the bum dope he puts out. I first started to notice it in this thread when he stated he applied Aldine with scotcsbrite, that is when I realized he had no idea what a water break free surface was. because if he had prepared the surface correctly all he needed to do to apply the Aldine was to spray it on, and it would turn the color it was supposed to.
And now he advises that the paint be removed from that corrosion with a scraper, that tells me he doesn't realize there is corrosion debris under the paint which will be left in the aluminum to continue to corrode. picture how a scrapper could remove debris in the pits caused by the corrosion. Does that make any sense to anyone?

Then he has proven he doesn't understand that Stainless steel is harder than aluminum, and will leave no dissimilar metals behind to contaminate the aluminum base metal. Then he refers to the AC that does not apply to aircraft that are supported by the own manuals.

Now I see that he advocates using Scotchbrite to remove corrosion, well that is an abrasive that he worries about, and will remove the top coat of protective pure aluminum and actually make matters worse. What actually happens when this is done is to sand down the surrounding area to the level of the deepest pit removing aluminum that needn't be removed, which in turn leaves more base metal exposed.
Glen does not exhibit the actual experience that comes with working with General Aviation aircraft, He reads internet stuff and doesn't understand what he reads, or use the common sense that comes with experience, this is demonstrated by his thinking a stainless steel brush is not good to use on aluminum, because it is abrasive, then turns an about face and advised Scotchbrite. which really is.
The reason I could not polish Mike's 34V was because the paint shop that did the last paint job scuffed the aluminum with Scotch Brite, they scratched thru the outer layer of aluminum, believe me that layer was placed there for a reason. buff, scratch or grind it away is simply self defeating in corrosion prevention.

And yes I should ignore him, but then you folks would not get the proper information. I've been working aviation since 1954, there isn't much I haven't seen, and in this aging fleet corrosion is a big problem, and most of it is caused by old ill advised methods of treating it.
there was a day when we used high speed abrasive grinding wheels to remove paint and corrosion, but we can't use them on most of the GA fleet because we are dealing with .016" thick material.
I have already advised the op how to treat this bubble of corrosion by the least harmful method that will eliminate his problem and not cause further damage.
Unless Glen replies with something really stupid this will be my last post in this thread.
 
Tom-D said:
Granger can call them any thing they want, but until you understand the nobility of metals and the Brinell hardness you'll never understand why they are called platers brushes.

do you know why the chrome platers use them?
Click to expand...
We're not talking about Noble metals, but I'll play along.

Chromium is in the same material group (4) as Corrosion Resistant Steel, there would be no problem there.

Aluminum Alloys are in group 1&2.

That means that Aluminum and Stainless Steel are most reactive together.

I've worked for an airline that also had a 145 repair station. As an Inspector I did my time in the NDT shop. We had a Rockwell Hardness Tester, I was qualified on it. We mostly confirmed material heat treat for our structures shop.

I knew what you were referring to by "platers brush", I also happen to know it's a common term for small wire brushes, too.

We do Cadmium plating in our structures shop. I buy off on it. Wanna talk about the platers brush used there? It's a cloth brush.
 
Tom-D said:
Actually I have the problem with the bum dope he puts out. I first started to notice it in this thread when he stated he applied Aldine with scotcsbrite, that is when I realized he had no idea what a water break free surface was. because if he had prepared the surface correctly all he needed to do to apply the Aldine was to spray it on, and it would turn the color it was supposed to.
And now he advises that the paint be removed from that corrosion with a scraper, that tells me he doesn't realize there is corrosion debris under the paint which will be left in the aluminum to continue to corrode. picture how a scrapper could remove debris in the pits caused by the corrosion. Does that make any sense to anyone?

Then he has proven he doesn't understand that Stainless steel is harder than aluminum, and will leave no dissimilar metals behind to contaminate the aluminum base metal. Then he refers to the AC that does not apply to aircraft that are supported by the own manuals.

Now I see that he advocates using Scotchbrite to remove corrosion, well that is an abrasive that he worries about, and will remove the top coat of protective pure aluminum and actually make matters worse. What actually happens when this is done is to sand down the surrounding area to the level of the deepest pit removing aluminum that needn't be removed, which in turn leaves more base metal exposed.
Glen does not exhibit the actual experience that comes with working with General Aviation aircraft, He reads internet stuff and doesn't understand what he reads, or use the common sense that comes with experience, this is demonstrated by his thinking a stainless steel brush is not good to use on aluminum, because it is abrasive, then turns an about face and advised Scotchbrite. which really is.
The reason I could not polish Mike's 34V was because the paint shop that did the last paint job scuffed the aluminum with Scotch Brite, they scratched thru the outer layer of aluminum, believe me that layer was placed there for a reason. buff, scratch or grind it away is simply self defeating in corrosion prevention.

And yes I should ignore him, but then you folks would not get the proper information. I've been working aviation since 1954, there isn't much I haven't seen, and in this aging fleet corrosion is a big problem, and most of it is caused by old ill advised methods of treating it.
there was a day when we used high speed abrasive grinding wheels to remove paint and corrosion, but we can't use them on most of the GA fleet because we are dealing with .016" thick material.
I have already advised the op how to treat this bubble of corrosion by the least harmful method that will eliminate his problem and not cause further damage.
Unless Glen replies with something really stupid this will be my last post in this thread.
Click to expand...
I mean in general man. Say your piece, let Glenn tear it apart, and be done. You don't need to defend yourself or your honor. Let your knowledge speak for itself. The tit for tat with him is making me hate both of you, and I really want to like you despite the way you portray yourself sometimes.

Glenn is also the guy that said you have to carry 100% of your maintenance logs in your aircraft for a ramp check. He clearly is incapable of separating 91 and 135 and it shows. As my girlfriend would say... "stay in your lane and you do you boo."
 
ircphoenix said:
I mean in general man. Say your piece, let Glenn tear it apart, and be done. You don't need to defend yourself or your honor. Let your knowledge speak for itself. The tit for tat with him is making me hate both of you, and I really want to like you despite the way you portray yourself sometimes.

Glenn is also the guy that said you have to carry 100% of your maintenance logs in your aircraft for a ramp check. He clearly is incapable of separating 91 and 135 and it shows. As my girlfriend would say... "stay in your lane and you do you boo."
Click to expand...
Provide a link to where I said you have to carry 100% of your maintenance logs. You can't, because I didn't.

Part 91 is really very broad.

Part 91 Subpart F applies to large and turbine powered multi engine airplanes, like airliners.

Part 91.1411 - 91.1443 applies to Continuous Airworthiness Maintenance Programs, like airlines.

Both areas, I'm more than familiar with.
 
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Tom-D said:
Actually I have the problem with the bum dope he puts out. I first started to notice it in this thread when he stated he applied Aldine with scotcsbrite, that is when I realized he had no idea what a water break free surface was. because if he had prepared the surface correctly all he needed to do to apply the Aldine was to spray it on, and it would turn the color it was supposed to.
And now he advises that the paint be removed from that corrosion with a scraper, that tells me he doesn't realize there is corrosion debris under the paint which will be left in the aluminum to continue to corrode. picture how a scrapper could remove debris in the pits caused by the corrosion. Does that make any sense to anyone?

Then he has proven he doesn't understand that Stainless steel is harder than aluminum, and will leave no dissimilar metals behind to contaminate the aluminum base metal. Then he refers to the AC that does not apply to aircraft that are supported by the own manuals.

Now I see that he advocates using Scotchbrite to remove corrosion, well that is an abrasive that he worries about, and will remove the top coat of protective pure aluminum and actually make matters worse. What actually happens when this is done is to sand down the surrounding area to the level of the deepest pit removing aluminum that needn't be removed, which in turn leaves more base metal exposed.
Glen does not exhibit the actual experience that comes with working with General Aviation aircraft, He reads internet stuff and doesn't understand what he reads, or use the common sense that comes with experience, this is demonstrated by his thinking a stainless steel brush is not good to use on aluminum, because it is abrasive, then turns an about face and advised Scotchbrite. which really is.
The reason I could not polish Mike's 34V was because the paint shop that did the last paint job scuffed the aluminum with Scotch Brite, they scratched thru the outer layer of aluminum, believe me that layer was placed there for a reason. buff, scratch or grind it away is simply self defeating in corrosion prevention.

And yes I should ignore him, but then you folks would not get the proper information. I've been working aviation since 1954, there isn't much I haven't seen, and in this aging fleet corrosion is a big problem, and most of it is caused by old ill advised methods of treating it.
there was a day when we used high speed abrasive grinding wheels to remove paint and corrosion, but we can't use them on most of the GA fleet because we are dealing with .016" thick material.
I have already advised the op how to treat this bubble of corrosion by the least harmful method that will eliminate his problem and not cause further damage.
Unless Glen replies with something really stupid this will be my last post in this thread.
Click to expand...
Tom, your reading comprehension sucks, you twist just about everything you quote from somebody.

Show me where "I stated I applied Aldine with scotcsbrite". You can't.

I advised to: "carefully remove the bubbled paint (preferably with a sharp nonmetallic scraper) and see what ya got. I've seen spots like that, that were corrosion and on the rare occasion not corroded." Those were just initial instructions, not complete instructions. I still stand by it, however if I were doing it to my aircraft I'd slice the bubble off with a razor blade, even though I have access to plastic scrapers that are very sharp, and hard.

The fact that 43.13 states to not use Stainless Steel abrasives on Aluminum gives you no clue that there might be a problem with doing it? Yet, that's what you advise.

On one hand you're concerned about a plastic scrapers damaging cladding and on the other you're not concerned with stainless steel, which you admit is harder than aluminum. You make no sense. Besides that, the "good" paint will act as a guide, limiting the amount of material removed by the scraper.

We us Scotchbright pads to remove corrosion all the time, they are a much better choice for corrosion removal than a dissimilar metal.

Pure aluminum cladding is there for alloy corrosion prevention, it varies in thickness, it is generally between 0.001" to 0.005" thick. Rest assured, if it's corroded under that paint bubble, the cladding is long gone. And to address why I say "If", because, again based upon experience, there is a slight chance that it's not corroded. I've seen it a few times, and everyone was shocked because they were sure it would have been.

And to refresh your memory, this was in my first post, post #2 in this thread:
"Follow manufactures manual, which will be: corrosion removal, determine if remaining material thickness is within limits, treat, prime and paint."
 
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This has been a very informative thread, but I'm still not sure what should be done. I have an isolated area near my hatch handle, so I've been following the responses with some interest. I'm not sure how to expose it, scrape it or treat it. And someone mentioned something about a rock.
 
GlennAB1 said:
And to refresh your memory, this was in my first post, post #2 in this thread:
"Follow manufactures manual, which will be: corrosion removal, determine if remaining material thickness is within limits, treat, prime and paint."
Click to expand...
then prove you were right, and show us the info in a piper MM.

your statement show us all how little you know about the content of a GA MM
 
When any one needs my help, contact me thru the "conversation mode" it arrives in my e-mail.
 
ircphoenix said:
Glenn is also the guy that said you have to carry 100% of your maintenance logs in your aircraft for a ramp check. He clearly is incapable of separating 91 and 135 and it shows. As my girlfriend would say... "stay in your lane and you do you boo."
Click to expand...

Thank you, I thought I was the only one :)
 
Tom-D said:
then prove you were right, and show us the info in a piper MM.
your statement show us all how little you know about the content of a GA MM
Click to expand...

So the MM requires repairs to be made in accordance with AC 43.13, I know you must hate to see that.

PIPER AIRCRAFT
PA-28-236
MAINTENANCE MANUAL

STRUCTURAL REPAIRS
Structural repairs must be made in accordance with the regulations set forth in FAA Advisory Circular 43-13-lA.

http://www.p28b.com/sites/default/files/PA28-236ServiceManual.pdf

page 2E21
 
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@Tom-D wouldn't the thin layer on top be aluminum oxide, and stripping that away exposes the base metal which opens it up for further corrosion? Not picking nits, but remembering something from my sailing days
 
GlennAB1 said:
Plastic or phenolic scrapers are recommended when working with aluminum, even clad aluminum.
Stainless steel is bad advice. Refer to table 6-1 in 43.13-1B if you don't believe me
Click to expand...
Tom-D said:
Do you really still believe that applies to an aircraft that is supported by its own manuals?
Click to expand...
And when the manufacturer's own manual states you must use AC 43.13? I must LOL.
 
Tom-D said:
This is what.
Click to expand...
Seriously? You asked. That lapseam you are so proud is pitted all to hell and fastener holes are elongated.
And you stated "on most of the GA fleet because we are dealing with .016" thick material."
Most manufacturers allow for 10% corrosion/damage removal/clean-up before strengthening or replacement is required. That's just over one and a half thousanths (0.0016"), not very much when you consider that's probably all the cladding thickness is.
sferguson524 said:
@Tom-D wouldn't the thin layer on top be aluminum oxide, and stripping that away exposes the base metal which opens it up for further corrosion? Not picking nits, but remembering something from my sailing days
Click to expand...
Excellent question since Tom's project has such widespread corrosion.

I sure wouldnt be posting those pictures on here and saying I bought it with the intention of fixing it to sell.
 
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Is there a new anti-corrosion plating solution called "Aldine"? I know what Alodine is, but I've never heard of Aldine. And are we talking about the clear Alodine or the yellow stuff that is a chromium compound?

Thanks,

Jim
 
Capt. Geoffrey Thorpe said:
If it was my airplane, scotchbright and a rattlecan. It ain't like it's the effing the space shuttle.

But I ain't no A&P so I don't know the secret handshake and can't write the magic paperwork.
Click to expand...
It's the "secret handshake" I'm looking for. I know mechanics do use auto primer and paint with the same ingredients, at least on unpressurized airplanes. I'm trying to find out if it is technically proper. Is there that much of a difference between the Dupont Imron car and airplane products?
 
https://www.faa.gov/documentLibrary/media/Advisory_Circular/Chapter_06.pdf

If you are flying a King Air or Learjet, then maybe there is a difference between automotive and aircraft specific paint. If you are flying a Cessna or Piper spam can, take an inspection panel of the same colour to your local automotive paint dealer and have them match it with (fill in the paint make). For small touch ups, a tube of touch-up paint from a dealer would work. Or order via Aircraft Spruce if you wish. http://www.aircraftspruce.com/catalog/cspages/pti-touch-up.php


I wouldn't fret over the odd spot of corrosion. Treat as necessary and fly on. I would be more concerned about the exfoliating spar under the wing panel that has never been off or the spar carry through above the headliner that has never been opened. These aircraft were never meant to be flying this long and they need owners who are willing to spend the time and money to keep them airworthy.
 
JAWS said:
These aircraft were never meant to be flying this long and they need owners who are willing to spend the time and money to keep them airworthy.
Click to expand...
Same with airliners. We'd still be operating 727's if they hadn't made the aging aircraft inspections so extreme.
 
jakem said:
It's the "secret handshake" I'm looking for. I know mechanics do use auto primer and paint with the same ingredients, at least on unpressurized airplanes. I'm trying to find out if it is technically proper. Is there that much of a difference between the Dupont Imron car and airplane products?
Click to expand...
Talk to your AI to make sure he/she/it isn't going to have some kind of **** fit and to get a recommendation for a primer.

You can dig through here: http://www.faa.gov/documentLibrary/media/Advisory_Circular/Chapter_06.pdf if you have nothing better to do:

"The removal of corrosion prod-
ucts by hand can be accomplished by use of
aluminum grit and silicon carbide abrasive,
such as non-woven, non-metallic, abrasive mat
(Spec. MIL-A-9962), abrasive cloth, and pa-
per. Aluminum wool, fiber bristle brushes, and
pumice powder are also acceptable methods.

Stainless steel brush (Spec.
H-B-178, type
III, class 2) may be used as long
as the bristles do not exceed 0.010 inch in di-
ameter. After use of this brush the surface
should be polished with 60 grit aluminum ox-
ide abrasive paper, then with 400 grit alumi-
num oxide paper Care should be exercised in
any cleaning process to avoid breaking the
protective film.

Steel wool, emery cloth, steel
wire brushes (except stainless steel brush)
copper alloy brushes, rotary wire brushes, or
severe abrasive materials should not be used
on any aluminum surface"
blah blah blah

But I would use Scotchbright and a rattle can. I would stay away from sandpaper to minimize the removal of the aluminum cladding on you skins which is only about one thousandths of an inch thick (but is already gone where it is actually corroded). (Again, I ain't no A&P, so all my advice is wrong.)

Imron is hard to patch perfectly and generally pretty toxic, but unless you are messing with fabric - paint is pretty much paint.
 
Capt. Geoffrey Thorpe said:
Talk to your AI to make sure he/she/it isn't going to have some kind of **** fit and to get a recommendation for a primer.

You can dig through here: http://www.faa.gov/documentLibrary/media/Advisory_Circular/Chapter_06.pdf if you have nothing better to do:

"The removal of corrosion prod-
ucts by hand can be accomplished by use of
aluminum grit and silicon carbide abrasive,
such as non-woven, non-metallic, abrasive mat
(Spec. MIL-A-9962), abrasive cloth, and pa-
per. Aluminum wool, fiber bristle brushes, and
pumice powder are also acceptable methods.

Stainless steel brush (Spec.
H-B-178, type
III, class 2) may be used as long
as the bristles do not exceed 0.010 inch in di-
ameter. After use of this brush the surface
should be polished with 60 grit aluminum ox-
ide abrasive paper, then with 400 grit alumi-
num oxide paper Care should be exercised in
any cleaning process to avoid breaking the
protective film.

Steel wool, emery cloth, steel
wire brushes (except stainless steel brush)
copper alloy brushes, rotary wire brushes, or
severe abrasive materials should not be used
on any aluminum surface"
blah blah blah

But I would use Scotchbright and a rattle can. I would stay away from sandpaper to minimize the removal of the aluminum cladding on you skins which is only about one thousandths of an inch thick (but is already gone where it is actually corroded). (Again, I ain't no A&P, so all my advice is wrong.)

Imron is hard to patch perfectly and generally pretty toxic, but unless you are messing with fabric - paint is pretty much paint.
Click to expand...
I've been waiting for days for Tom to find that, he obviously doesn't use AC 43.13, even when the manufacturer requires it. Remember he uses:
Tom-D said:
Folks... they teach General shop practices in A&P school. and their curriculum is approved by the Administrator. :)
Click to expand...
 
Last edited:
GlennAB1 said:
I've been waiting for days for Tom to find that, he obviously doesn't use AC 43.13, even when the manufacturer requires it. Remember he uses:
Click to expand...
fact is, no one taught you general shop practices, or you know what to use on al-clad skin.
Plus you'd know a any scraper will not remove corrosion products from aluminum with out removing the al-clad.
and further more, you'd know no one should rub a hard scraper on .016" aluminum skins with out distorting it.
 
Last edited:
Capt. Geoffrey Thorpe said:
Talk to your AI to make sure he/she/it isn't going to have some kind of **** fit and to get a recommendation for a primer.

You can dig through here: http://www.faa.gov/documentLibrary/media/Advisory_Circular/Chapter_06.pdf if you have nothing better to do:

"The removal of corrosion prod-
ucts by hand can be accomplished by use of
aluminum grit and silicon carbide abrasive,
such as non-woven, non-metallic, abrasive mat
(Spec. MIL-A-9962), abrasive cloth, and pa-
per. Aluminum wool, fiber bristle brushes, and
pumice powder are also acceptable methods.

Stainless steel brush (Spec.
H-B-178, type
III, class 2) may be used as long
as the bristles do not exceed 0.010 inch in di-
ameter. After use of this brush the surface
should be polished with 60 grit aluminum ox-
ide abrasive paper, then with 400 grit alumi-
num oxide paper Care should be exercised in
any cleaning process to avoid breaking the
protective film.

Steel wool, emery cloth, steel
wire brushes (except stainless steel brush)
copper alloy brushes, rotary wire brushes, or
severe abrasive materials should not be used
on any aluminum surface"
blah blah blah

But I would use Scotchbright and a rattle can. I would stay away from sandpaper to minimize the removal of the aluminum cladding on you skins which is only about one thousandths of an inch thick (but is already gone where it is actually corroded). (Again, I ain't no A&P, so all my advice is wrong.)

Imron is hard to patch perfectly and generally pretty toxic, but unless you are messing with fabric - paint is pretty much paint.
Click to expand...
That info is well over 50 years old, we have much better methods now.
WE can do this type of corrosion product removal with out sanding away any thing.
 

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You guys and Gals listen to Glen, we metalsmiths love replacing skins.
 
Tom-D said:
True, like you've never seen that color because you apply it over an oily surface.
Click to expand...
It was a joke, relax.

And, nope. We follow manufacturers procedures that require the metal to just start to take a gold to light brown color.
 
Last edited:
Tom-D said:
fact is, no one taught you general shop practices, or you know what to use on al-clad skin.
Plus you'd know a any scraper will not remove corrosion products from aluminum with out removing the al-clad.
and further more, you'd know no one should rub a hard scraper on .016" aluminum skins with out distorting it.
Click to expand...
Tom, I said scrape the paint off and see what you got. That was not corrosion removal instruction.

No hard plastic scrapers allowed but sanding is ok as is evident in the pictures you posted. Just look at the edge of the paint, you used something abrasive like sandpaper. And you make a big deal about a plastic scraper....
 
Tom-D said:
That info is well over 50 years old, we have much better methods now.
WE can do this type of corrosion product removal with out sanding away any thing.
Click to expand...
Bull. AC 43.13-1A, dated 1988 was cancelled when AC 43.13 1B came out in 1998.

Maybe you can, but it's obvious you've sanded. The scratches left behind extend from the metal onto the orange paint.
 
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Tom-D said:
You guys and Gals listen to Glen, we metalsmiths love replacing skins.
Click to expand...
AC 43.13 requires corrosion blend out and polishing afterwards. You haven't done that. Your finished lap seam has pits, tool marks, scribe lines, scratches, elongated holes from misdrilling. Metalsmith?
 
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