Corrosion On Propeller Leading Edge

How about you explain the TC-4C Propeller controls and indications, you've worked that Gulfstream (so you have said) and I'm sure you are clueless about the propeller system.
You ignored the last question I asked you about major difference between the TC-4C and G-1, I expect the same for this one.
 
Last edited:
GlennAB1 said:
How about you explain the TC-4C Propeller controls and indications, you've worked that Gulfstream (so you have said) and I'm sure you are clueless about the propeller system.
You ignored the last question I asked you about major difference between the TC-4C and G-1, I expect the same for this one.
Click to expand...
There again you made a wrong assumption, I never worked for Gulfstream. I was a contractor for the NAVY TC-4C program. (as a metalsmith)

All props and engines were rental. we did nothing to the props and only daily maintenance to the engines when directed by the rental owners.

And yes we adheared to the manuals provided.
 
GlennAB1 said:
Pretty funny, you don't want to follow manuals any other time... LOL
Click to expand...
That's a lie,, how would you know what I do? ever seen any of my work?
NO you just make sheet up as you go.
 
GlennAB1 said:
Once again, you can't read. I wrote "that Gulfstream" not at Gulfstream.
Click to expand...
Why would that matter when you can't recognize a prop when you see one?

all your babbling in this thread and couldn't fine the proper reference for a Sensenich prop.

I guess you can't find anything unless it is on a job card and then have an engineer explain it to ya.
 
GlennAB1 said:
There again, the G-1could be part 91, so that would be another - for you.
Click to expand...
I showed you a Steerman, with a Pratt 450 horse 985, and you think it is a G-1, (typical).
 
You say only certified prop shops can perform maintenance on props. Are you a certified prop shop? Evidently not. So, what makes you a propeller expert? Answer: Bullsh!t.
 
Last edited:
TylerSC said:
After reading up on corrosion, I decided to take some 220 sandpaper and smooth it out. It didnt take much hand sanding at all to get to clean metal.
Click to expand...
After reading this thread, I'm pretty sure you have already crashed and died. Or, possibly, everything is safe and legal.
One or the other.
 
AKBill said:
Stewardb has a good point. When I was in the Navy we dressed the props on the P-3 with 300 grit (or so)
emery cloth then fine scotchbrite then alodine. It was a Hamilton Standard prop.
Click to expand...

NEVER use emery cloth on aluminum. Emery is made with aluminum oxide set in iron oxide. The iron is forced into the aluminum and immediately starts reacting with it, corroding it. That could easily be the source of the white residue some of you are seeing on leading edges.

Use the black waterproof sandpaper, which has silicon carbide grit, or aluminum oxide cloth or paper.

Emery Cloth Construction

Emery cloth is a strip of dense fabric that has small metallic or synthetic particles bonded to it with glues and adhesives. It's best used to smooth metal surfaces. The small metallic particles often include bits of aluminum oxide that are set in iron oxide. Emery cloth is especially helpful in eradicating rust, eliminating corrosion, polishing metal and removing paint from metal surfaces. It shouldn't be used on wood surfaces because the tiny bits of iron can permanently damage natural wood.
 
JAWS said:
Yes, that does sound reasonable. There are a few more steps, including certifying the preventative maintenance, but you got the general idea. Anything more, a mechanic should be consulted.
Excerpt from the Sensenich repair manual below.

View attachment 57125
Click to expand...


There are three terms: Shall, Should, and Can. Shall means you must comply. Thinks FARs. Should is a recommendation, to be followed if you know what's best for you. Can means "May;" an available option.
 
Dan Thomas said:
NEVER use emery cloth on aluminum. Emery is made with aluminum oxide set in iron oxide. The iron is forced into the aluminum and immediately starts reacting with it, corroding it. That could easily be the source of the white residue some of you are seeing on leading edges.

Use the black waterproof sandpaper, which has silicon carbide grit, or aluminum oxide cloth or paper.
Click to expand...

This is from AC 20-37E. Please explain what I am not understanding regarding the use of emery cloth. Thanks.


(2) Leading or Trailing Edge Damage. Refer to the propeller manufacturer’s maintenance documents for instructions on how to repair this damage. However, if the manufacturer did not publish this information, the following repairs can be made. For nicks, dents, pits, and cuts in the leading or trailing edges of blades, ensure that the bottom of the damage is removed first by rounding out and fairing in the repair only slightly deeper than the damage. Initial removal of material should be done using a fine cut file. All traces of file marks in the repaired area should be removed with number 240 emery cloth followed by polishing with number 320 emery cloth, then finished with crocus cloth or 600 grit emery cloth, and then visually inspected. An individual edge repair should not exceed a depth of 3/16-inch. The depth of repair should be greater than the depth of damage as given in Table 2-1. When repaired areas do not overlap, more than one repair may be accomplished. The repair length should be 10 times longer than the depth of the repair as shown in Figure 2-5, Techniques for Blade Repair. Refer to manufacturer’s instructions for repairs aft of the leading edge sections of the blade. For damage exceeding depths shown in Table 2-1, use the specific propeller manufacturer’s repair manual limits.

Par
 
Where is FAA approved sandpaper? Seriously, the actual composition of any you buy otc is probably mostly unknown.

That all aside, I'd like to remind everyone that steel tools are used all over aluminum aircraft. How do you think all those rivet holes get there? There are many steel fasteners in aviation press/interference fit, into aluminum structures.

There's always a better way to do something and there's a way that will work today.
 
Dan Thomas said:
https://books.google.ca/books?id=smchAgAAQBAJ&pg=PT433&dq=emery+cloth++aluminum+corrosion&hl=en&sa=X&ved=0ahUKEwjhr42Hp8nXAhUBRWMKHQCkDfwQ6AEIKjAB#v=onepage&q=emery cloth aluminum corrosion&f=false

https://books.google.ca/books?id=NuRurL0jsgUC&pg=PA90&dq=emery+cloth++aluminum+corrosion&hl=en&sa=X&ved=0ahUKEwjhr42Hp8nXAhUBRWMKHQCkDfwQ6AEIMDAC#v=onepage&q=emery cloth aluminum corrosion&f=false
Click to expand...
I picking up what you are putting down. I just don't see were the FAA could be in so ill advised in stating use emery cloth in the AC 20-37e. If you have not contacted the FAA about what you believe is a concern your bad.

I have no problem changing the way I proceed or preform maintenance. Education is good for all, please educate with documentation the FAA has published.
 
Last edited:
If I had a prop hat had corrosion on its leading edge, I'd simply go fly..
It will clean its self up.
after all, what removed the protective coating in the first place?
that same thing will shine up the leading edge
 
Tom-D said:
If I had a prop hat had corrosion on its leading edge, I'd simply go fly..
It will clean its self up.
after all, what removed the protective coating in the first place?
that same thing will shine up the leading edge
Click to expand...
Theres some sound advice from an A&P. Just ignore it, it'll go away.
 
Tom-D said:
If I had a prop hat had corrosion on its leading edge, I'd simply go fly..
It will clean its self up.
after all, what removed the protective coating in the first place?
that same thing will shine up the leading edge
Click to expand...

Tom's Maintenance 101! :rolleyes:

Tom-D said:
All propellers have a repair manual, it is just a matter of who can do the repairs given in them. you as an owner sure as hell can't, Me as an A&P can't, Me as an A&P-IA can't.

Every thing in that manual is a major propeller repair, and requires a prop shop DOM or trained repair man to return to service.
Click to expand...
 
Checkout_my_Six said:
yup.....ostrich maintenance. :eek:
Click to expand...
Most times it better to do nothing than to make a big mistake?

So, you guys think it's better to tell the OP to grind on the prop. So the A&P-IA at next annual can tell them to get a new prop. Only makes sense here, because there ain't a sole here got a dime invested, or have seen the prop in question.
 
Whats really funny on this page/site every one has a hissy fit if you'd polish a prop, but is telling this guy to take sand paper to it.

Can't have it both ways.
 
"a lot of roughness and some minor pitting" on a propeller leading edge, and you say do nothing.

Pretty much, everybody else says to do what manuals or the FAA says.
 
AKBill said:
I picking up what you are putting down. I just don't see were the FAA could be in so ill advised in stating use emery cloth in the AC 20-37e. If you have not contacted the FAA about what you believe is a concern your bad.

I have no problem changing the way I proceed or preform maintenance. Education is good for all, please educate with documentation the FAA has published.
Click to expand...

Oh. The FAA would never be wrong or inconsistent. Hm.

AC43.13-1B, Para. 6-136(d)(1)(c) on page 6-26, says this:

(c)
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.
 
bnt83 said:
That all aside, I'd like to remind everyone that steel tools are used all over aluminum aircraft. How do you think all those rivet holes get there? There are many steel fasteners in aviation press/interference fit, into aluminum structures.
Click to expand...

Steel tools used on aluminum have a completely different mechanism from abrasive tools. I have files and drills I have used for years--some files over 20 years old--that are still sharp. Using files and drills on steel are what ruins them, mostly. A drill bit or file scoops the metal off. If it dulls it's because it was overheated or abused in some way and the fine edges are broken away or rounded by overheating. Abrasives "cut" by dragging material off, not by scooping, and the resulting surface is completely different from that left by a cutting tool. Anyone who has examined an abraded surface under a microscope of at least 1000X power--as I did during research into honed finish problems in compressor cylinders in the 1980s--will be shocked at the torn appearance left behind, even by "fine" abrasives. Add to that the fact that abrasives are deliberately designed to allow their dulled grit to break away and expose underlying, sharper grains, and we have a problem with surface contamination. Aluminum oxide, the typical grit, won't cause corrosion, but the iron oxide added to emery cloth sure will.

A high-speed steel drill bit will drill hundreds of holes in aluminum. A file will dress hundreds of propeller blades. A piece of emery will be shot in a few minutes of hand sanding.

Those steel fasteners cause trouble in aluminum structures. Any floatplane mechanic sees that all the time. The aluminum around the steel fastener disappears.

55898959_scaled_618x308.jpg
 
You must log in or register to reply here.
Back
Top