Prop touch-up

[JAWS]

My knowledge comes from experience, And I know that when aluminum has been coated with oil of any kind it requires much more than turpentine to get alodine to do what it is required to do, and to add paint over paint that has a contaminate in it, is never been advised by any painter.
I'll learn that Alodine is an acid and can't be neutral PH, But what I was taught many years ago by those I respected stays with me.
To add, the advice I've given on how to deal with this prop, Is directly from dealing with props and prop shops almost daily and how to get the best for your dollar.
If you like you do as you please, but remember one of us is an A&P-IA the other a chemist.

My experience isn't your experience. So does that make it less applicable or relevant?

What makes Tom-D the ONLY voice of reason when it comes to aircraft maintenance?

For those interested below is how you use alodine 1201. Also, it is no longer called alodine, but "Bonderite 1201 Aero".

http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgSAIB.nsf/(LookupSAIBs)/HQ-18-09?OpenDocument

https://www.aircraftspruce.com/catalog/pdf/09-01619tds.pdf

 

[JAWS]

So, given what you have seen, what kind of money are we talking about if I take it to a prop shop? I understand you can't know exactly, but I don't know if I should expect $500 or $5000. First time.

Hope for the best, but plan for the worst. Take it all one step at a time. Get the damage evaluated to see if it is field repairable. If it isn't, then start on plan B. If you really just want it removed and sent in and gone over for your piece of mind, do that.

Heck I operate off of 3000' of good asphalt. The hangar apron has deteriorated into about 50% gravel over the years. I usually warm up for a minute at about 800 RPM and then roll over to the good asphalt without adding power to finish warming up. I do have to add a little bump of power to get up on the taxiway since there is a pretty good hump, but it's momentary. Also have to give a little nudge of power when I park to get lined up to back it in the hangar. I dunno, maybe I just suck.

My planes fly out of everything from 10,000 foot asphalt to 2500 foot gravel. The ramps are worse than the actual runways. Mine carry a small push broom to clean under the props before starts on contaminated ramps.

Sometimes XXit happens. They come home, I get a call, I fix and certify and they go again.

 

[Tom-D]

So, given what you have seen, what kind of money are we talking about if I take it to a prop shop?

Call these guys and see, I know nothing about them, I simply did a search for prop shops near you.
FOSTER'S PROPELLER SERVICE, INC

F.A.A. REPAIR STATION NUMBER F3PR014N

26650 Highway 62

Boynton, OK. 74422

voice: 918-733-2131

fax: 918-733-2086

fosterpropeller@windstream.net

 

[Tom-D]

My experience isn't your experience. So does that make it less applicable or relevant?
No but be right or get corrected just like anyone. I certainly get corrected often enough.
I made a statement about PH factor, and got jumped on like it meant anything to this thread.
What makes Tom-D the ONLY voice of reason when it comes to aircraft maintenance?

Neither of us are, but Tom -D doesn't say stuff isn't airworthy, unless he can show why. I ask for a rule to prove it isn't airworthy, hoping you could, and you give me an inspection requirement.
You see a picture not knowing what magnification it was taken and draw conclusions. The only conclusion I drew was it needed to be taken care of.
But you and I both made the same recommendation = go get it fixed by a Mechanic / prop shop.
More often than not, I agree with your input, and simply not say anything.

 

[Tom-D]

For those interested below is how you use alodine 1201. Also, it is no longer called alodine, but "Bonderite 1201 Aero".

http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgSAIB.nsf/(LookupSAIBs)/HQ-18-09?OpenDocument

https://www.aircraftspruce.com/catalog/pdf/09-01619tds.pdf

This is good stuff, I use it rather than Alodine 1200, (which you can still get). but on both stand by for huge shipping haz-mat costs.

OBTW, did you know that bonderite 1001 is the non staining type. = leaves no color change.

 

[Tom-D]

Put Alodine 1200 in the search window.


http://www.westernamspec.com/Inventory/DoSearch.asp

 

[Briar Rabbit]

Call these guys and see, I know nothing about them, I simply did a search for prop shops near you.
FOSTER'S PROPELLER SERVICE, INC

F.A.A. REPAIR STATION NUMBER F3PR014N

26650 Highway 62

Boynton, OK. 74422

voice: 918-733-2131

fax: 918-733-2086

fosterpropeller@windstream.net

I used this man’s father to repair a prop in 1970 and was very pleased with the outcome. I have been told he does a pretty good job too and is one of two shops in Oklahoma I would recommend. I would have to look up the name of the other shop in Tulsa if you want it. You will probably be paying 4 digits for the repair. A new prop, Hartzell or McCauley probably close to $10K. Also if you want to turn it into a 180 (remove that front training wheel) there are stc’s to do that on some 182 models.

 

[JAWS]

Neither of us are, but Tom -D doesn't say stuff isn't airworthy, unless he can show why. I ask for a rule to prove it isn't airworthy, hoping you could, and you give me an inspection requirement.

Then how can anything be considered "not airworthy"? Nicks in props, there is no specific reg that covers that. Crack in the spar? Not in the regs. Frayed elevator cable, not in the regs either. The specific words are not there, but there are standards available - maintenance manuals, ICAs, AC43.13, overhaul manuals, etc.


What is the definition of "Airworthiness"? Meeting the type certificate and safe for flight. And how do we meet these two things? Read an actual C of A - "
Terms and Conditions. Indicates the Airworthiness Certificate is in effect indefinitely if the aircraft is maintained in accordance with 14 CFR parts 21, 43, and 91, and the aircraft is registered in the United States.". Canadian C of A's have much the same wording.

My quote was in reference to the comment that the aircraft had nicks and erosion to some degree during at least one annual.

Maybe I over-reached a bit, but I am conservative when it comes to airworthiness.

 

[Tom-D]

Then how can anything be considered "not airworthy"? Nicks in props, there is no specific reg that covers that. Crack in the spar? Not in the regs. Frayed elevator cable, not in the regs either. The specific words are not there, but there are standards available - maintenance manuals, ICAs, AC43.13, overhaul manuals, etc.


What is the definition of "Airworthiness"? Meeting the type certificate and safe for flight. And how do we meet these two things? Read an actual C of A - "
Terms and Conditions. Indicates the Airworthiness Certificate is in effect indefinitely if the aircraft is maintained in accordance with 14 CFR parts 21, 43, and 91, and the aircraft is registered in the United States.". Canadian C of A's have much the same wording.

My quote was in reference to the comment that the aircraft had nicks and erosion to some degree during at least one annual.

Maybe I over-reached a bit, but I am conservative when it comes to airworthiness.

The only criteria there is to condemn a prop is if the pit is deep enough to not be blendable, You had no way to know that. yet made the statement that is was unairworthy.

 

[Cap'n Jack]

I do get that ,,, now
But please explain how turpentine will leave a clean enough surface to apply alodine?

You might also want to know that you have been on ignore until early today, might explain why you didn't get answers.

Now I think I'll put on ignore again.

Meh, go ahead, put me on ignore. Turpentine dissolves the oil, and the CorrosionX in it. After the oil is removed, the excess turpentine evaporates.

My knowledge comes from experience, And I know that when aluminum has been coated with oil of any kind it requires much more than turpentine to get alodine to do what it is required to do, and to add paint over paint that has a contaminate in it, is never been advised by any painter.
I'll learn that Alodine is an acid and can't be neutral PH, But what I was taught many years ago by those I respected stays with me.
To add, the advice I've given on how to deal with this prop, Is directly from dealing with props and prop shops almost daily and how to get the best for your dollar.
If you like you do as you please, but remember one of us is an A&P-IA the other a chemist.

True, but the chemist tries not to post beyond their knowledge.

I also recall these threads from the A&P-IA:
https://www.pilotsofamerica.com/community/threads/is-it-time-to-quit.86554/
https://www.pilotsofamerica.com/community/threads/an-a-p-iss-best-insurance.99197/

This NTSB report came from those threads:
See: https://www.ntsb.gov/investigations...ev_id=20150928X72825&ntsbno=WPR15FA268&akey=1

That the items below were called out suggest that they aren't standard practices.

The original engine oil screen remained installed, despite the fact that the engine was equipped with an oil filter.

It was noted that there was no torque seal on any of the cylinder attachment nuts. Each cylinder was removed, and visually inspected. With the exception of the number two cylinder, it was noted that there was a significant amount of black sealant type material covering the majority of the cylinder flange and skirt; the number two cylinder was void of a black sealant type material. It was also noted that one of the number two cylinder hold down nuts appeared to be a standard nut, in contrast to typical cylinder hold down nuts.

It was noted that there was black sealant applied to the crankcase halves mating surfaces, and there was no silk thread noted on the crankcase halve mating surfaces. It was also noted that the black sealant material was found in several of the oil galleys.

 

[1RTK1]

So, given what you have seen, what kind of money are we talking about if I take it to a prop shop? I understand you can't know exactly, but I don't know if I should expect $500 or $5000. First time..

My fixed pitch was about $600 if I recall

 

[JAWS]

The only criteria there is to condemn a prop is if the pit is deep enough to not be blendable, You had no way to know that. yet made the statement that is was unairworthy.

So what depth of nick is considered airworthy? Please quote the actual number and the specific regulation that you got it from.

 

[Tom-D]

So what depth of nick is considered airworthy? Please quote the actual number and the specific regulation that you got it from.

There is no actual number, so how can you decide any would be unairworthy? The depth of a blendable deviation will vary with how much of the blade has been removed by previous repairs. legally if you blend a blade and you are not below the min blade profile you are still airworthy.

 

[Tom-D]

From AC20-37E
c. Minor Repairs of Aluminum Blades. Limited minor repairs may be made on propellers by appropriately rated maintenance technicians either on the aircraft or when the propeller is removed. Minor dents, cuts, scars, scratches, and nicks may be removed providing their removal does not weaken the blade, substantially change weight or balance, or otherwise impair its performance. The following paragraphs give guidance on the methods for accomplishing minor repairs. Before attempting to repair a propeller blade, determine whether the propeller manufacturer has published damage limits that govern repair procedures applicable to that part. Do not attempt a repair without knowing exactly what minor repairs, if any, are permissible. For example, straightening or reforming a blade is not considered a minor repair. Manufactures’ service documents and AC 43.13-1, current edition, provide additional repair instruction.

So, there ya go. The FAA doesn't give you a number, but the manufacturer may. But I know of no manufacturer that will allow you to go below minimum blade profile.

If I believe it is even close, its going to a prop shop for repair.

 

[timwinters]

The internet is hard.

Four pages later....

 

[Cap'n Jack]

From AC20-37E
c. Minor Repairs of Aluminum Blades. Limited minor repairs may be made on propellers by appropriately rated maintenance technicians either on the aircraft or when the propeller is removed. Minor dents, cuts, scars, scratches, and nicks may be removed providing their removal does not weaken the blade, substantially change weight or balance, or otherwise impair its performance. The following paragraphs give guidance on the methods for accomplishing minor repairs. Before attempting to repair a propeller blade, determine whether the propeller manufacturer has published damage limits that govern repair procedures applicable to that part. Do not attempt a repair without knowing exactly what minor repairs, if any, are permissible. For example, straightening or reforming a blade is not considered a minor repair. Manufactures’ service documents and AC 43.13-1, current edition, provide additional repair instruction.

So, there ya go. The FAA doesn't give you a number, but the manufacturer may. But I know of no manufacturer that will allow you to go below minimum blade profile.

If I believe it is even close, its going to a prop shop for repair.

Interesting that AC20-37E is quoted here (https://www.faa.gov/documentLibrary/media/Advisory_Circular/AC_20-37e.pdf) given the comments below

Why not strip and polish the whole thing ?

Seems Tim has the right of it:

Maybe because in most cases this renders the prop unairworthy?

From AC20-37E, link above:

The FAA receives frequent inquiries from airplane owners and maintenance personnel asking whether it is acceptable to polish propeller blades. It is almost always not acceptable. Corrosion protection such as paint and anodize should not be removed from the surface of a propeller blade.

The same source also mentions maximum "size" of a repair. Logic suggests that damage larger than these limits may not be done.
For blade face damage:

An individual repair should not exceed 1/16-inch in depth and the surface radius of curvature of the repair must not be less than 3/8-inch. Repair width should be 30 times the repair depth as shown in Figure 2-5. More than one repair is permitted when repair areas do not overlap an identical blade radius

They also provide limits on leading-edge damage as well.

 

[Tom-D]

Four pages later....

And to follow up :
it was announced by our chemist that corrosion X could be cleaned up with turpentine, I did a little experiment this morning, Taking a regular piece of 2024- sheet, I cleaned it with turpentine and acetone in two areas. placed alodine 1001 on it and saw what happens. all it does is bead up.
Then I cleaned it again with an etch and reapplied the bonerite 1001 (alodine) to see what happened.
You must have what is known as a water brake free surface to use any of these treatments. (alodine 1200/ 1001) and any of the thinners will not give you that, they are all oil based, it required an etch that will leave the aluminum chemically clean.
Now prior to our favorite chemist comes back with " it's good enough for just painting", no its not, because with out proper cleaning and treatment, you are just making matters worse by hiding the problem.

 

[Tom-D]

Four pages later....

Have you learned any thing yet? or did you know it all before.

 

[timwinters]

Have you learned any thing yet? or did you know it all before.

I knew it all before, Tom. That is I knew to discount anything you say as being legitimate or true. Not that everything you say isn't rather that I simply can't trust that it is.

I have learned to place far more faith in the opinions of the other A&Ps here.

 

[JAWS]

There is no actual number, so how can you decide any would be unairworthy?

Nope. Go read AC43.13 or the McCauley operators manual that you refuse to acknowledge. Recall the quote from an actual C of A earlier.

"... the Airworthiness Certificate is in effect indefinitely if the aircraft is maintained in accordance with 14 CFR parts 21, 43, and 91..."

.

The depth of a blendable deviation will vary with how much of the blade has been removed by previous repairs. legally if you blend a blade and you are not below the min blade profile you are still airworthy.

But above you are saying that there is no criteria to go off of, so therefore it is always airworthy. If always airworthy, why would any prop ever be dressed in the field? That is a dangerous attitude to have. But yet, Tom has said earlier "have file, will travel", so some where he does believe in dressing damage out of props. Very confusing!

Aircraft and props are either airworthy or they are not - there is no middle ground.

 

[Tom-D]

Nope. Go read AC43.13 or the McCauley operators manual that you refuse to acknowledge. Recall the quote from an actual C of A earlier..
But above you are saying that there is no criteria to go off of, so therefore it is always airworthy. If always airworthy, why would any prop ever be dressed in the field? That is a dangerous attitude to have. But yet, Tom has said earlier "have file, will travel", so some where he does believe in dressing damage out of props. Very confusing!

Aircraft and props are either airworthy or they are not - there is no middle ground.

What you don't seem to get is, you didn't have any criteria to make any decision as to airworthiness.
And next time get the right AC, read the purpose paragraph of each. if you are going to chose which one to follow.
Yes I have a file, and a lot more including the instructions for continued airworthiness for McCauley props and the equipment to do minor maintenance, and the proper rating.

 

[Tom-D]

Very confusing!
Aircraft and props are either airworthy or they are not - there is no middle ground.

It wouldn't be confusing if you knew the rules, You don't seem to know the A&P-IA in the US has the ability to determine airworthiness during an annual.
Or the amount they can be blended, and still be airworthy, yet you admitted you've already done worse, and called it good.
and to top if off you made all your statements based upon a picture on the internet.

 

[JAWS]

you admitted you've already done worse, and called it good

Yes I did. One large nick, that was evaluated to be just within field repair specs and was dressed using manufacturer's directions.

 

[JAWS]

you made all your statements based upon a picture on the internet.

PSST. Hey, Tom. ANY nick in a prop can technically cause the prop to be unairworthy. As the saying goes, a picture is worth a thousand words.

But I am sure you know better than McCauley, Hartzell, Sensenich, AC43.13, etc, etc.

 

[Tom-D]

PSST. Hey, Tom. ANY nick in a prop can technically cause the prop to be unairworthy. As the saying goes, a picture is worth a thousand words.

But I am sure you know better than McCauley, Hartzell, Sensenich, AC43.13, etc, etc.

Do we have manuals for McCauley props that contradict the 43,13? I wonder which takes precedence? the ICAs for McCAuley or the 43,13?

Knowing the obvious, escapes you.

OBTW, what criteria in the prop pictures did you use the make your decision on its airworthiness?

 

[Cap'n Jack]

And to follow up :
it was announced by our chemist that corrosion X could be cleaned up with turpentine, I did a little experiment this morning, Taking a regular piece of 2024- sheet, I cleaned it with turpentine and acetone in two areas. placed alodine 1001 on it and saw what happens. all it does is bead up.
Then I cleaned it again with an etch and reapplied the bonerite 1001 (alodine) to see what happened.
You must have what is known as a water brake free surface to use any of these treatments. (alodine 1200/ 1001) and any of the thinners will not give you that, they are all oil based, it required an etch that will leave the aluminum chemically clean.
Now prior to our favorite chemist comes back with " it's good enough for just painting", no its not, because with out proper cleaning and treatment, you are just making matters worse by hiding the problem.

No quite sure what he did there...doesn't look like the CorrosionX was applied (not stated either), looks like he just tried to clean sheet metal with an unknown protectant.

The stain is not permanent and may be removed with naphtha or mineral spirits.

From the CorrosionX datasheet:
https://www.fmv.se/FTP/M7789-000193/datablad/M0722-257096_Corrorion_X_Aviation_Spray.pdf

 

[JAWS]

You can lead a horse to water, but you can't make him drink! I need to keep that one in mind!

 

[Tom-D]

I need to keep that one in mind!

What you really should keep in mind is, you don't judge the condition of a prop from a picture.
You need to have hands on and the proper maintenance manuals for the job. not some magnified picture that you can go OMG somebody is going to die.

 

[Cap'n Jack]

You can lead a horse to water, but you can't make him drink! I need to keep that one in mind!

Or Equus africanus

 

[Tom-D]

No quite sure what he did there..

Very simple, the sheet of aluminum was cleaned with turpentine, and it left a film that would not allow the alodine to work.
When the cleaner is not an etch (such as al-u-prep) it leaves a film.

Try it your self. You must have a water break free surface, you won't get that with any of the commercial cleaners like Turpentine, acetone, paint thinners.
and when you have a layer of paint involved that has been contaminated, it is even worse.

 

[Tom-D]

Or Equus africanus

Figures,, as soon as your proven wrong, you start calling names.

 

[Cap'n Jack]

Very simple, the sheet of aluminum was cleaned with turpentine, and it left a film that would not allow the alodine to work.
When the cleaner is not an etch (such as al-u-prep) it leaves a film.

Try it your self. You must have a water break free surface, you won't get that with any of the commercial cleaners like Turpentine, acetone, paint thinners.
and when you have a layer of paint involved that has been contaminated, it is even worse.

Got it. There was no CorrosionX applied. So the experiment you did was out of the context of the original statement.

 

[Checkout_my_Six]

Tom....what argument are you trying to win?

 

[Tom-D]

Tom....what argument are you trying to win?

Simply, if you clean aluminum and get a surface like this, alodine will not work.

If you won't believe me try it your self.

 

[Checkout_my_Six]

Tom....read the label and do what it sez....and stop it with the chemistry talk.

 

[Tom-D]

Tom....read the label and do what it sez....and stop it with the chemistry talk.

No longer chemistry talk, try it. Alodine is a acid, but not strong enough to be it own cleaner.
so post the label lets see what it says.

 

[Tom-D]

directions for use (aircraft spruce and speciality)

After precleaning with BONDERITE C-IC 33 AERO, rinse with water. Apply without dilution by brushing or swabbing with sponge. Rinse with water and surface is ready for paint. This is a visible coating which leaves the surface with a golden coloration. The alodized surface provides protection against weather and firmly bonds paint. 1 quart treats about 100 sq. ft. Flammable. Available in quart and gallon sized.
HAZARDOUS

note, it don't say turpentine or any other cleaner

 

[Tom-D]

http://www.na.henkel-adhesives.com/adhesives/product-search-1554.htm?nodeid=8797865738241

 

[JCranford]

Byam's at Meacham would do a full prop overhaul on a 3 blade McCauley for around 3500. Word around town is they woulda/coulda/shoulda fixed a slightly bend 3 blade McCauley for around $800...

 

[Tom-D]

Byam's at Meacham would do a full prop overhaul on a 3 blade McCauley for around 3500. Word around town is they woulda/coulda/shoulda fixed a slightly bend 3 blade McCauley for around $800...

Isn't $800 about what a new blade costs?