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Signs of corrosion on tail cone

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Mauledriver(at)nc.rr.com
Guest

Posted: Wed Jul 29, 2015 1:11 pm Post subject: Signs of corrosion on tail cone

I'm beginning to see signs of corrosion between the top skin and the 

side skins of my tailcone.  The corrosion is happening underneath the 

paint.  Inside the tailcone there are a few 'wisps' of grayish corrosion 

coming up from the same joint which is riveted to the angle longerons.



Anyone else experiencing this?  What are you finding, what have you done?



Plane is hangared except when traveling and only occassionally sees salt 

air - and I wash it down after each encounter.

cooprv7(at)yahoo.com
Guest

Posted: Wed Jul 29, 2015 1:59 pm Post subject: Signs of corrosion on tail cone

I’m not sure if this will help with corrosion already there, but I sprayed the tailbone with Corrosion X and the film is still there after 7 years and 720 hours.  I appreciate you bringing this up though as it wouldn’t hurt to apply again.  One gotcha, do NOT apply this until after you paint your airplane, otherwise it will be a bear to get the paint to adhere properly.



Marcus

 	  Quote: 	
		   On Jul 30, 2015, at 12:05 AM, Bill Watson <Mauledriver(at)nc.rr.com> wrote:

 

 

 

 I'm beginning to see signs of corrosion between the top skin and the side skins of my tailcone.  The corrosion is happening underneath the paint.  Inside the tailcone there are a few 'wisps' of grayish corrosion coming up from the same joint which is riveted to the angle longerons.

 

 Anyone else experiencing this?  What are you finding, what have you done?

 

 Plane is hangared except when traveling and only occassionally sees salt air - and I wash it down after each encounter.

carl.froehlich(at)verizon
Guest

Posted: Wed Jul 29, 2015 2:14 pm Post subject: Signs of corrosion on tail cone

Is this a quick build?



Carl



 	  Quote: 	
		   On Jul 29, 2015, at 2:05 PM, Bill Watson <Mauledriver(at)nc.rr.com> wrote:

 

 

 

 I'm beginning to see signs of corrosion between the top skin and the side skins of my tailcone.  The corrosion is happening underneath the paint.  Inside the tailcone there are a few 'wisps' of grayish corrosion coming up from the same joint which is riveted to the angle longerons.

 

 Anyone else experiencing this?  What are you finding, what have you done?

 

 Plane is hangared except when traveling and only occassionally sees salt air - and I wash it down after each encounter.

Mauledriver(at)nc.rr.com
Guest

Posted: Wed Jul 29, 2015 5:53 pm Post subject: Signs of corrosion on tail cone

Yes, but I build the tailcone.  No relationship between the two I would 

think.



On 7/29/2015 6:11 PM, Carl Froehlich wrote:

 	  Quote: 	
		   



 Is this a quick build?



 Carl



> On Jul 29, 2015, at 2:05 PM, Bill Watson <Mauledriver(at)nc.rr.com> wrote:

>

> 

>

> I'm beginning to see signs of corrosion between the top skin and the side skins of my tailcone.  The corrosion is happening underneath the paint.  Inside the tailcone there are a few 'wisps' of grayish corrosion coming up from the same joint which is riveted to the angle longerons.

>

> Anyone else experiencing this?  What are you finding, what have you done?

>

> Plane is hangared except when traveling and only occassionally sees salt air - and I wash it down after each encounter.

>

>

 -----

 No virus found in this message.

 Checked by AVG - www.avg.com

rv10pro(at)gmail.com
Guest

Posted: Thu Jul 30, 2015 6:11 am Post subject: Signs of corrosion on tail cone

#1 Surface preparation.  Many on this list talk of Acetone or Alcohol cleaning.  Aluminum begins Aluminum Oxide within an hour of scotchbrighting.  Doing the work in a high humidity environment or an area under the influence of Salt vapor can impact the surface prep in short order.  Correction: do an evaporation test of the solvent used on a piece of clear glass and see if after evaporation, deposits form.  Prime within 15 minutes of scotchbrighting never hours or days.



#2 Galvanic action by use of the airframe as the ground path from adjacent electrical circuits is another.  Run a separate return path from lighting components forward to a more substantial frame member not in contact with exterior skin if using single wire power runs.

#3 Use of chemicals which promotes Hydrolysis.  The old Simple Green before they reformulated Aviation grade was notorious.  Wicking action is best reduced by wet sealing the two skins with a roller of thin proseal.  RTV is not a cure all.

#4 "Faying action" between two close sheet metal items attached together wick most alkaline cleaners into the joints mentioned.  Clear rinse the joints with de-ionized water and pay particular attention to the areas showing signs.  Oxidation once started must be removed.  The cause corrected and the treated skin recoated with an Alodine or similar treatment.  It is remotely possible the primer had some impact on the outcome.

Least desireable Corrective Action: remove the skin and treat before the corrosion reaches 10% in skin depth.

Note:  Cessna had a very large batch of aircraft twenty years ago with Filiform corrosion which showed YEARS later.  The research found they were parking the prepped aircraft outside overnight provided Acid Rain vapor to condense on the material.  The skin was dry and "Clean" but the acid residual began working between the skin and final coats - after application.  Only solution, soda blast, properly reprep the surface and reapply a corrective topcoat.

The type of corrosion found helps determine the cause and corrective action.  Just shooting blind on a sensitive issue.  Good Luck with the solution.

John C.

#40600

On Wed, Jul 29, 2015 at 6:49 PM, Bill Watson <Mauledriver(at)nc.rr.com (Mauledriver(at)nc.rr.com)> wrote:

[quote]--> RV10-List message posted by: Bill Watson <Mauledriver(at)nc.rr.com (Mauledriver(at)nc.rr.com)>

 

 Yes, but I build the tailcone.  No relationship between the two I would think.

 

 On 7/29/2015 6:11 PM, Carl Froehlich wrote:

  	  Quote: 	
		   --> RV10-List message posted by: Carl Froehlich <carl.froehlich(at)verizon.net (carl.froehlich(at)verizon.net)>

 

 Is this a quick build?

 

 Carl

 

 

 

  	  Quote: 	
		   On Jul 29, 2015, at 2:05 PM, Bill Watson <Mauledriver(at)nc.rr.com (Mauledriver(at)nc.rr.com)> wrote:

 

 --> RV10-List message posted by: Bill Watson <Mauledriver(at)nc.rr.com (Mauledriver(at)nc.rr.com)>

 

 I'm beginning to see signs of corrosion between the top skin and the side skins of my tailcone.  The corrosion is happening underneath the paint.  Inside the tailcone there are a few 'wisps' of grayish corrosion coming up from the same joint which is riveted to the angle longerons.

 

 Anyone else experiencing this?  What are you finding, what have you done?

 

 Plane is hangared except when traveling and only occassionally sees salt air - and I wash it down after each encounter.

 

 

 

 

 	
 

 

 

 

 

 

 -----

 No virus found in this message.

 Checked by AVG - www.avg.com

 

 

 	
 

 

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 [b]

Kellym

Joined: 10 Jan 2006
Posts: 1706
Location: Sun Lakes AZ

Posted: Thu Jul 30, 2015 6:42 am Post subject: Signs of corrosion on tail cone

I will agree with all John wrote except the electrical ground issue. 

Given that type certified aircraft from the end of WWII on have used the 

airframe as a ground path, you would expect to see such problems if it 

were an issue, within say 30-40 years. Hasn't happened. My current 

aircraft is 50 yrs old. Not one bit of corrosion around any of the power 

consuming items that are grounded to the airframe, nor the ground attach 

points. IIRC Bob Nuckolls of AeroElectric connection says only 

electronics need central grounding, NOT lights, pitot heat, and other 

high current devices. Given he was the expert for Cessna, then Beech, I 

tend to listen to his opinions.

I will not that where Vans uses aluminum angle for longerons, etc. that 

aluminum angle is NOT Alclad, and requires some form of primer or 

anodizing. I don't believe any of the material Vans supplies has any 

primer, except in the quick build components, and I'm not sure they do 

anything between the skins and the longerons. Heck, on mine they didn't 

even bother to countersink the longerons where they attached to dimpled 

skins.



On 7/30/2015 7:08 AM, John Cox wrote:

 	  Quote: 	
		   #1 Surface preparation.  Many on this list talk of Acetone or Alcohol 

 cleaning.  Aluminum begins Aluminum Oxide within an hour of 

 scotchbrighting.  Doing the work in a high humidity environment or an 

 area under the influence of Salt vapor can impact the surface prep in 

 short order.  Correction: do an evaporation test of the solvent used 

 on a piece of clear glass and see if after evaporation, deposits 

 form.  Prime within 15 minutes of scotchbrighting never hours or days.



 #2 Galvanic action by use of the airframe as the ground path from 

 adjacent electrical circuits is another.  Run a separate return path 

 from lighting components forward to a more substantial frame member 

 not in contact with exterior skin if using single wire power runs.



 #3 Use of chemicals which promotes Hydrolysis.  The old Simple Green 

 before they reformulated Aviation grade was notorious.  Wicking action 

 is best reduced by wet sealing the two skins with a roller of thin 

 proseal.  RTV is not a cure all.

_________________
Kelly McMullen
A&P/IA, EAA Tech Counselor # 5286
KCHD

rv10pro(at)gmail.com
Guest

Posted: Thu Jul 30, 2015 7:13 am Post subject: Signs of corrosion on tail cone

Improper surface prep can and does lead to issues.  Did someone state Van's preps parts??  Not the company I know so well.  I will assume Bill did everything "Top Notch".  Washing of aircraft is another issue not discussed on this forum, yet.



Can give examples of electrolysis doing corrosion damage but was not intending to counter the disciples of Mr. Nuckholls.  SFAR88 has manufacturers rethinking due to FAA mandate the issues of electric current beyond electronics.  On our airliners which get 4400-4500 hours per year, the damage is accelerated.  Just a perspective.  Maybe Acid Rain can be blamed since Mr Nuckoll's was not retired at the time at Cessna when the filliform was such a large issue.

Not a supporter of Mr. Scott's mantra "Just Build It".    Build it safe, enjoy flight, live LONG.

jc

On Thu, Jul 30, 2015 at 7:38 AM, Kelly McMullen <kellym(at)aviating.com (kellym(at)aviating.com)> wrote:

[quote]--> RV10-List message posted by: Kelly McMullen <kellym(at)aviating.com (kellym(at)aviating.com)>

 

 I will agree with all John wrote except the electrical ground issue. Given that type certified aircraft from the end of WWII on have used the airframe as a ground path, you would expect to see such problems if it were an issue, within say 30-40 years. Hasn't happened. My current aircraft is 50 yrs old. Not one bit of corrosion around any of the power consuming items that are grounded to the airframe, nor the ground attach points. IIRC Bob Nuckolls of AeroElectric connection says only electronics need central grounding, NOT lights, pitot heat, and other high current devices. Given he was the expert for Cessna, then Beech, I tend to listen to his opinions.

 I will not that where Vans uses aluminum angle for longerons, etc. that aluminum angle is NOT Alclad, and requires some form of primer or anodizing. I don't believe any of the material Vans supplies has any primer, except in the quick build components, and I'm not sure they do anything between the skins and the longerons. Heck, on mine they didn't even bother to countersink the longerons where they attached to dimpled skins.

 

 On 7/30/2015 7:08 AM, John Cox wrote:

  	  Quote: 	
		   #1 Surface preparation.  Many on this list talk of Acetone or Alcohol cleaning.  Aluminum begins Aluminum Oxide within an hour of scotchbrighting.  Doing the work in a high humidity environment or an area under the influence of Salt vapor can impact the surface prep in short order.  Correction: do an evaporation test of the solvent used on a piece of clear glass and see if after evaporation, deposits form.  Prime within 15 minutes of scotchbrighting never hours or days.

 

 #2 Galvanic action by use of the airframe as the ground path from adjacent electrical circuits is another.  Run a separate return path from lighting components forward to a more substantial frame member not in contact with exterior skin if using single wire power runs.

 

 #3 Use of chemicals which promotes Hydrolysis.  The old Simple Green before they reformulated Aviation grade was notorious.  Wicking action is best reduced by wet sealing the two skins with a roller of thin proseal.  RTV is not a cure all.

 

 

 	
 

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[b]

Kellym

Joined: 10 Jan 2006
Posts: 1706
Location: Sun Lakes AZ

Posted: Thu Jul 30, 2015 7:30 am Post subject: Signs of corrosion on tail cone

Vans quick build components do get primer, I believe AFTER they are 

assembled.

Cessna's corrosion had nothing to do with electrics. It had to do with 

your mention of the overnight outside AND they eliminated one of the two 

components of the primer they were using. It was supposed to be done on 

two phases, not a single coat.



On 7/30/2015 8:09 AM, John Cox wrote:

 	  Quote: 	
		   Improper surface prep can and does lead to issues. Did someone state 

 Van's preps parts??  Not the company I know so well.  I will assume 

 Bill did everything "Top Notch".  Washing of aircraft is another issue 

 not discussed on this forum, yet.



 Can give examples of electrolysis doing corrosion damage but was not 

 intending to counter the disciples of Mr. Nuckholls.  SFAR88 has 

 manufacturers rethinking due to FAA mandate the issues of electric 

 current beyond electronics.  On our airliners which get 4400-4500 

 hours per year, the damage is accelerated.  Just a perspective.  Maybe 

 Acid Rain can be blamed since Mr Nuckoll's was not retired at the time 

 at Cessna when the filliform was such a large issue.



 Not a supporter of Mr. Scott's mantra "Just Build It".  Build it safe, 

 enjoy flight, live LONG.

 jc



 On Thu, Jul 30, 2015 at 7:38 AM, Kelly McMullen <kellym(at)aviating.com 

 <mailto:kellym(at)aviating.com>> wrote:



     

     <kellym(at)aviating.com <mailto:kellym(at)aviating.com>>



     I will agree with all John wrote except the electrical ground

     issue. Given that type certified aircraft from the end of WWII on

     have used the airframe as a ground path, you would expect to see

     such problems if it were an issue, within say 30-40 years. Hasn't

     happened. My current aircraft is 50 yrs old. Not one bit of

     corrosion around any of the power consuming items that are

     grounded to the airframe, nor the ground attach points. IIRC Bob

     Nuckolls of AeroElectric connection says only electronics need

     central grounding, NOT lights, pitot heat, and other high current

     devices. Given he was the expert for Cessna, then Beech, I tend to

     listen to his opinions.

     I will not that where Vans uses aluminum angle for longerons, etc.

     that aluminum angle is NOT Alclad, and requires some form of

     primer or anodizing. I don't believe any of the material Vans

     supplies has any primer, except in the quick build components, and

     I'm not sure they do anything between the skins and the longerons.

     Heck, on mine they didn't even bother to countersink the longerons

     where they attached to dimpled skins.



     On 7/30/2015 7:08 AM, John Cox wrote:



         #1 Surface preparation.  Many on this list talk of Acetone or

         Alcohol cleaning.  Aluminum begins Aluminum Oxide within an

         hour of scotchbrighting.  Doing the work in a high humidity

         environment or an area under the influence of Salt vapor can

         impact the surface prep in short order.  Correction: do an

         evaporation test of the solvent used on a piece of clear glass

         and see if after evaporation, deposits form.  Prime within 15

         minutes of scotchbrighting never hours or days.



         #2 Galvanic action by use of the airframe as the ground path

         from adjacent electrical circuits is another.  Run a separate

         return path from lighting components forward to a more

         substantial frame member not in contact with exterior skin if

         using single wire power runs.



         #3 Use of chemicals which promotes Hydrolysis.  The old Simple

         Green before they reformulated Aviation grade was notorious. 

         Wicking action is best reduced by wet sealing the two skins

         with a roller of thin proseal. RTV is not a cure all.



     ===========

     -List" rel="noreferrer"

     target="_blank">http://www.matronics.com/Navigator?RV10-List

     ===========

     FORUMS -

     eferrer" target="_blank">http://forums.matronics.com

     ===========

     b Site -

               -Matt Dralle, List Admin.

     rel="noreferrer" target="_blank">http://www.matronics.com/contribution

     ===========





 http://www.matronics.com/contribution

_________________
Kelly McMullen
A&P/IA, EAA Tech Counselor # 5286
KCHD

Bob Turner

Joined: 03 Jan 2009
Posts: 885
Location: Castro Valley, CA

Posted: Sat Aug 01, 2015 9:01 am Post subject: Re: Signs of corrosion on tail cone

I'd suggest getting a spray can of Corrosion X or ACF-50 and spraying along that joint and the angle. That stuff penetrates everywhere. It will not repair damage done but may stop or slow further damage.

_________________
Bob Turner
RV-10 QB

Mauledriver(at)nc.rr.com
Guest

Posted: Sat Aug 01, 2015 12:09 pm Post subject: Signs of corrosion on tail cone

Thanks John, a lot of good stuff there!

       

       Looks like I have some form of filiform  corrosion.  I sure looks       like 'something' leaked out from the seam after painting.

       

       I primed the tail feathers with epoxy primer, the tailcone with       Dupont wash primer, finished off the QB kit with rattle can       primer, I did not prime the angle longerons (!)

       

       The paint job included PreKote, epoxy primer and a Dupont       Polyurethane.

       

       My plan of action looks like 1) mechanically remove paint where       corrosion is evident, 2)remove corrosion, clean, (conversion?), 3)       prime and paint.  Then apply one of the penetrating corrosion       protection products to the inside of the tail cone along the seam.

       

       On 7/30/2015 10:08 AM, John Cox wrote:

     

     [quote]       #1 Surface preparation.  Many on this list talk of         Acetone or Alcohol cleaning.  Aluminum begins Aluminum Oxide         within an hour of scotchbrighting.  Doing the work in a high         humidity environment or an area under the influence of Salt         vapor can impact the surface prep in short order.  Correction:         do an evaporation test of the solvent used on a piece of clear         glass and see if after evaporation, deposits form.  Prime within         15 minutes of scotchbrighting never hours or days.         

         

         #2 Galvanic action by use of the airframe as the ground           path from adjacent electrical circuits is another.  Run a           separate return path from lighting components forward to a           more substantial frame member not in contact with exterior           skin if using single wire power runs.

         

         

         #3 Use of chemicals which promotes Hydrolysis.  The old           Simple Green before they reformulated Aviation grade was           notorious.  Wicking action is best reduced by wet sealing the           two skins with a roller of thin proseal.  RTV is not a cure           all.

         

         

         #4 "Faying action" between two close sheet metal items           attached together wick most alkaline cleaners into the joints           mentioned.  Clear rinse the joints with de-ionized water and           pay particular attention to the areas showing signs.            Oxidation once started must be removed.  The cause corrected           and the treated skin recoated with an Alodine or similar           treatment.  It is remotely possible the primer had some impact           on the outcome.

         

         

         Least desireable Corrective Action: remove the skin and           treat before the corrosion reaches 10% in skin depth.

         

         

         Note:  Cessna had a very large batch of aircraft twenty           years ago with Filiform corrosion which showed YEARS later.            The research found they were parking the prepped aircraft           outside overnight provided Acid Rain vapor to condense on the           material.  The skin was dry and "Clean" but the acid residual           began working between the skin and final coats - after           application.  Only solution, soda blast, properly reprep the           surface and reapply a corrective topcoat.

         

         

         The type of corrosion found helps determine the cause and           corrective action.  Just shooting blind on a sensitive issue.            Good Luck with the solution.

         

         

         John C.

         #40600

       

       

         On Wed, Jul 29, 2015 at 6:49 PM, Bill           Watson <Mauledriver(at)nc.rr.com (Mauledriver(at)nc.rr.com)>           wrote:

            	  Quote: 	
		  -->             RV10-List message posted by: Bill Watson <Mauledriver(at)nc.rr.com (Mauledriver(at)nc.rr.com)>

             

             Yes, but I build the tailcone.  No relationship between the             two I would think.

             

             On 7/29/2015 6:11 PM, Carl Froehlich wrote:

              	  Quote: 	
		                 --> RV10-List message posted by: Carl Froehlich <carl.froehlich(at)verizon.net (carl.froehlich(at)verizon.net)>

               

               Is this a quick build?

               

               Carl

               

               

               

                	  Quote: 	
		                   On Jul 29, 2015, at 2:05 PM, Bill Watson <Mauledriver(at)nc.rr.com (Mauledriver(at)nc.rr.com)>                 wrote:

                 

                 --> RV10-List message posted by: Bill Watson <Mauledriver(at)nc.rr.com (Mauledriver(at)nc.rr.com)>

                 

                 I'm beginning to see signs of corrosion between the top                 skin and the side skins of my tailcone.  The corrosion                 is happening underneath the paint.  Inside the tailcone                 there are a few 'wisps' of grayish corrosion coming up                 from the same joint which is riveted to the angle                 longerons.

                 

                 Anyone else experiencing this?  What are you finding,                 what have you done?

                 

                 Plane is hangared except when traveling and only                 occassionally sees salt air - and I wash it down after                 each encounter.

                 

                 

                 

                 

               	
               

               

               

               

               

               

               -----

               No virus found in this message.

               Checked by AVG - www.avg.com

               

               

             	
             

             

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             ===========

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             rel="noreferrer"             target="_blank">http://www.matronics.com/contribution

             ===========

             

             

             

           

	
       

No virus         found in this message.

         Checked by AVG - www.avg.com

         Date: 07/30/15     [b]

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