Prop touch-up

[Tom-D]

What would the problem be in just cleaning it well with nonabrasive cleanser then painting vs anodizing then painting???

First off, you can't ANODIZE you can ALODINE
There is no problem cleaning the blades as long as you don't scratch them, apply Alodine then repaint.
Alodine is a 6% solution of Chromic Acid, with a neutral PH factor, Yes it is a very weak acid, that produces an artificial hydroxide coating of the surface of clean aluminum.

Anodizing is a electro-chemical process that will produce corrosion-resistant, anodic oxide finish on the aluminum. This is a much better protection than a mere etch as in alodine.
This is why this coating should not be removed, WE in the field can not reproduce it.
anodizing

 

[Tom-D]

What would the problem be in just cleaning it well with nonabrasive cleanser then painting vs anodizing then painting???

The only problem I see with this case is, he already has a greasy material on the prop. Now that becomes a problem of getting it clean enough for anything to stick.
Anything that will get the greasy stuff off well enough, will take the grease impregnated paint with it.
Then what would you have? -- A nice clean blade that needs painting so... if you are going to do anything, do it all, or nothing.

 

[OkieFlyer]

It's not just a different opinion or his condescension. He makes posts beyond his knowledge and continues to assert his own set of facts even when they are shown to be wrong. The problem is that someone asking for help doesn't know where his knowledge ends and where the BS begins which can lead to a bad decision. I question whether he actually does know more about it. I agree with you about the price in messing it up.

Perhaps it's a flaw, or perhaps it's not, but I prefer to be nice at all cost It's the Okie way.

 

[Cap'n Jack]

First off, you can't ANODIZE you can ALODINE
There is no problem cleaning the blades as long as you don't scratch them, apply Alodine then repaint.
Alodine is a 6% solution of Chromic Acid, with a neutral PH factor, Yes it is a very weak acid, that produces an artificial hydroxide coating of the surface of clean aluminum.

Anodizing is a electro-chemical process that will produce corrosion-resistant, anodic oxide finish on the aluminum. This is a much better protection than a mere etch as in alodine.
This is why this coating should not be removed, WE in the field can not reproduce it.
anodizing

Wow. All kinds of fail here.
Chromic acid is an acid. It's pH will be acidic, not neutral. 6% will be below pH 3 (see: http://www.aqion.de/site/191 ).
There isn't simply an etch going on, but also deposition of chromium ions which provide some protection. There isn't a defined layer from the chrome conversion either. Alodine is a brand name for chrome conversion.

Chromate conversion treatments actually take advantage of this high surface activity. Through use of a strong oxidizing agent such as chromic acid, CrO 3, a redox reaction occurs at acidic pH (pH -- 2) where hexavalent chromium, either in the form of Cr204- or HCrO3, is reduced to trivalent chromium while aluminum is oxidized to trivalent aluminum

See: https://materialsdata.nist.gov/bitstream/handle/11115/198/Chromate Conversion Coatings.pdf?sequence=3

 

[Cap'n Jack]

Perhaps it's a flaw, or perhaps it's not, but I prefer to be nice at all cost It's the Okie way.

No, it's not a flaw on your part. I'm torn between allowing poor advice to be unchallenged or keeping quiet about it. Keep in mind that this is the internet, caveat emptor. Look at the postings, and then verify if they make sense.

 

[Cap'n Jack]

The only problem I see with this case is, he already has a greasy material on the prop. Now that becomes a problem of getting it clean enough for anything to stick.
Anything that will get the greasy stuff off well enough, will take the grease impregnated paint with it.
Then what would you have? -- A nice clean blade that needs painting so... if you are going to do anything, do it all, or nothing.

Depends on the paint. The greasy stuff will come off with turpentine, many paints aren't touched by it. CorrosionX is dissolved in mineral oil, so turpentine should take it off well.

 

[OkieFlyer]

So, at the risk of everyone in the room gasping and telling me to drop everything and get that dangerous hunk of dilapidated aluminum to the shop before I kill my self and my family, then lambasted, tarred and feathered, screwed, blued, and tattooed for continuing to operate it, here's the prop in question.

Gulp........

Here goes........

I'm scared......

The worst of it.

 

[Checkout_my_Six]

OMG.....that's sand blasted....ain't no magic left on that.

 

[OkieFlyer]

From the front:

 

[OkieFlyer]

OMG.....that's sand blasted.

Wrong. Asphalt blasted

Deep breath.......Let 'er rip, boys.

 

[Checkout_my_Six]

Tom could fix that....I think.

 

[OkieFlyer]

Anybody need the smelling salts?

 

[Tarheelpilot]

That prop needs more than cleaning and paint

 

[JAWS]

Holy cow!

Um ... I ... er ... ah ... well you know!

My advice? Get a mechanic to look at that mess. Maybe it can be dressed out, depending on the depth of the damage and if there would be enough blade left after the repair. Don't be surprised if a prop shop gets involved in the end.

That is pretty bad, even by Canadian standards!

PS I looked again. I have seen worse and have possibly dressed out worse (just one bad ding, not multiple as shown). One needs to tread carefully with that amount of damage. That is skirting the fine line between field reparable and a trip to the prop shop.

PPS That prop is not airworthy as is. Please get it looked at and fixed.

 

[1RTK1]

First off, you can't ANODIZE you can ALODINE

Don’t know why I said anodize, alodine is what I should have said, I do understand the difference.

The only problem I see with this case is, he already has a greasy material on the prop. Now that becomes a problem of getting it clean enough for anything to stick.
Anything that will get the greasy stuff off well enough, will take the grease impregnated paint with it.
Then what would you have? -- A nice clean blade that needs painting so... if you are going to do anything, do it all, or nothing.

I was thinking dawn detergent for cleaning, hell they use it to clean animals after oil spills and it seems to work pretty well for them

 

[OkieFlyer]

That prop needs more than cleaning and paint

I know

Actually didn't seem as bad as the pictures look, but I guess it is.

I didn't want to show them, but I'll take my licks.

 

[Tom-D]

My advice? Get a mechanic to look at that mess. Maybe it can be dressed out, depending on the depth of the damage and if there would be enough blade left after the repair.

Up to there ya had it right.

PPS That prop is not airworthy as is. Please get it looked at and fixed.

That's where ya lost it. You don't know if it is with in blend limits or not, neither do I.

Until an A&P puts hands on, and makes a decision we don't know anything from the pictures.

That said, I didn't see anything that would scare me. There are a lot of props out there that are way worse than that.

 

[Tom-D]

That prop needs more than cleaning and paint

Yeah,, it needs the stress risers blended out stripped and re-finished. ALL minor repairs IAW the FAA's Recommendations in AC20-37E.
If the blades do not meet minimum blade profile after the stress risers are blended, then a prop shop must change the blades. But you 'd be amazed at how much metal you must remove before you reach minimum blade profile.

Do not read me wrong, I do believe this prop needs to go in for IRAN now, the pilot owner does not have the rating to care for it on the aircraft.
So I'd recommend that he fly it to the nearest prop shop and let them do the job.

 

[Tom-D]

I know

Actually didn't seem as bad as the pictures look, but I guess it is.

I didn't want to show them, but I'll take my licks.

No problems we all live and learn, but now is the time to do what's right.
get it repaired by a prop shop.
Do not tell them to overhaul it, simply tell them to inspect and repair as required. That way they can save your blades and a bunch of your money.

 

[Tom-D]

OMG.....that's sand blasted....ain't no magic left on that.

A lot more than what you'd think.

 

[Tom-D]

Tom could fix that....I think.

Fly me to OK see what happens.

Have file will travel..

 

[Tarheelpilot]

I know

Actually didn't seem as bad as the pictures look, but I guess it is.

I didn't want to show them, but I'll take my licks.

Don’t let it slide. Having the prop cleaned up and inspected is much cheaper than a failure of the prop. From what I can see in your pics I’m not seeing an immanent failure but there are very heavy loads on a prop. Not a mx area I skimp on.

 

[JAWS]

That's where ya lost it. You don't know if it is with in blend limits or not, neither do I.

I don't need to know whether it is at or below max field repair limits to know it isn't airworthy. That is my evaluation of the current condition based on the pictures provided. What the owner does is his decision. Maybe the prop will be just fine with some major dressing, maybe it is junk. That determination has yet to be made by the appropriate person.

 

[Tom-D]

I don't need to know whether it is at or below max field repair limits to know it isn't airworthy. That is my evaluation of the current condition based on the pictures provided. What the owner does is his decision. Maybe the prop will be just fine with some major dressing, maybe it is junk. That determination has yet to be made by the appropriate person.

you have no way of knowing if those nicks are deep enough to be unairworthy.

 

[JAWS]

That said, I didn't see anything that would scare me. There are a lot of props out there that are way worse than that.

It is rationalized that it is ok.

So I'd recommend that he fly it to the nearest prop shop and let them do the job.

And then next it just has to go to a prop shop.

Fly me to OK see what happens.

Have file will travel..

And then "let me at it!".

Good grief!!

 

[Tom-D]

It is rationalized that it is ok.



And then next it just has to go to a prop shop.



And then "let me at it!".

Good grief!!

Quote out of context much?

 

[Tom-D]

That is pretty bad, even by Canadian standards!

PS I looked again. I have seen worse and have possibly dressed out worse

And Tom's the bad one

 

[PaulS]

That prop needs some love.

 

[Timbeck2]

Looks like most, if not all, can be blended but its tough by just looking at a picture. My biggest concern would be that large square shaped chip in the center of the picture.

 

[JAWS]

PS I looked again. I have seen worse and have possibly dressed out worse (just one bad ding, not multiple as shown). One needs to tread carefully with that amount of damage. That is skirting the fine line between field reparable and a trip to the prop shop.

What I wrote.

Quote out of context much?

Right back atcha!

 

[Checkout_my_Six]

Tom would gnaw on that....

 

[Skip Miller]

That prop needs some love.

Like that floozie on the corner love requires money!

-Skip

 

[JCranford]

Your prop tips look a little bent. I'd get that to a shop...

 

[455 Bravo Uniform]

Looks like some gouges on the back too.

 

[OkieFlyer]

Don’t let it slide. Having the prop cleaned up and inspected is much cheaper than a failure of the prop. From what I can see in your pics I’m not seeing an immanent failure but there are very heavy loads on a prop. Not a mx area I skimp on.

Agreed. I've got some catching up to do, and I'll admit I'm a bit embarrassed to have let it go this long. It was basically just like that when I bought it 3 years ago, so shame on me for letting it go. On the other hand, no less than 2 IAs and 3 A&Ps have seen it an not done anything, so I just went with that. Now that I'm becoming more learned as an owner, it kind hacks me off that the mechanics never said "hey, we need to dress your prop, dude."

Looks like most, if not all, can be blended but its tough by just looking at a picture. My biggest concern would be that large square shaped chip in the center of the picture.

That big ding you're referring to is precisely the one I wanted you to see. Truthfully, and I'm not in denial, the extreme close-up makes it look worse than it is. I'm pretty darn sure almost all of it can be blended. That big one is the one I worry about. It's not quite as deep as it appears in the photo, but it is substantial. Need to find somebody good at dressing to tackle it. I don't think my usual A&P is up to the task.

Your prop tips look a little bent. I'd get that to a shop...

I thought those were just winglets...er.....proplets. Heck, I saw 'em. Still went flyin'.

 

[Timbeck2]

Andrew said: I don't think my usual A&P is up to the task.

Granted I have a background in jet engine mechanics and I've blended many a blade but reading a blending limit chart and using a file isn't all that difficult. If your mechanic isn't up to the task, its time to find one that is. If your dude can't blend and dress a prop by all means do NOT strip out a helicoil removing a spark plug.

 

[JAWS]

If your guy is hesitant by all means find someone you trust who can do the work. Props tend to get neglected, yet are pretty important.

The big ding wouldn't necessarily be the biggest problem in the picture to me. There is a score mark on the face, toward the tip, running fore and aft. That mark looks sharp and deep. A small but sharp nick in the wrong spot can be worse than a larger one in a relatively happier area.

The blending area is doubled on the face and back for good reason.

 

[Tom-D]

OkieFlyer is not qualified to blend a prop. He has no A&P near by, and some wonder why I say fly it to a prop shop and get it fixed.

This is what I love about internet trouble shooting, every body is an expert.
Even tho, they don't know at what magnifying rate that photo was taken. Yet they can determine it is not airworthy.

A&P-IA doing an annual are supposed to be determining airworthiness, So in their opinion it was, and said nothing. They actually saw it, and made a decision, I'll go with that.
FLY that sucker and go get it fixed.

 

[Tom-D]

If your guy is hesitant by all means find someone you trust who can do the work. Props tend to get neglected, yet are pretty important.

The big ding wouldn't necessarily be the biggest problem in the picture to me. There is a score mark on the face, toward the tip, running fore and aft. That mark looks sharp and deep. A small but sharp nick in the wrong spot can be worse than a larger one in a relatively happier area.

The blending area is doubled on the face and back for good reason.

Props are robust and much more sturdy than many give them credit for.
That prop is no worse Than many flying today. The last mechanic didn't believe it was a hazard, I'll go with that.
Those were new blades to start, and can have a huge amount of metal removed before they will be below blade profile.
If you look and compare the radius of the leading edge to the depth of these pits they appear to be less than 1/8" deep. I'll wager that a good prop shop will blend the leading edge alodine and send him on his way.

 

[Tom-D]

If your guy is hesitant by all means find someone you trust who can do the work. Props tend to get neglected, yet are pretty important.

The big ding wouldn't necessarily be the biggest problem in the picture to me. There is a score mark on the face, toward the tip, running fore and aft. That mark looks sharp and deep. A small but sharp nick in the wrong spot can be worse than a larger one in a relatively happier area.

The blending area is doubled on the face and back for good reason.

Sounds to me like yer trying to scare the owner out of a paycheck.