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Leak Proofing the Fuel Sender

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patrick.pulis(at)seagas.c
Guest

Posted: Mon Jul 28, 2008 6:10 pm Post subject: Leak Proofing the Fuel Sender

pascal(at)rv10builder.net
Guest

Posted: Tue Jul 29, 2008 6:12 am Post subject: Leak Proofing the Fuel Sender

Patrick;

 I followed Tim's insight and used proseal around  the gasket. I have heard of many other options as many mentioned the difficulty  of removing it later, if needed.

 http://www.myrv10.com/N104CD/wing/20041107/RV200411060023.html

  

 I figure if Proseal is used for the whole tank it  should work fine for the gasket.

  

 Pascal

  

  

 [quote]         From: Patrick Pulis 

Sent: Tuesday,    29 July 2008 11:37 AM

To: 'rv10-list(at)matronics.com' ([email]\'rv10-list(at)matronics.com\'[/email])

Subject:    RE: Leak Proofing the Fuel Sender

   

    According to the    installation instruction supplied with the stock standard fuel tank sender    supplied by Vans, it is recommended that the supplied neoprene gasket be    installed between the tank wall and the sender unit (and replaced if the    sender is ever removed for inspection/replacement).    

Other than the recommendation to use the gasket, there are no specific    instructions as to the use (or otherwise) of any fuel proofing compound (e.g.    - Proseal) to leak proof the installation of the float sender    unit.   

I have elected to use sealed nut plates (in lieu of the Vans standard) to    attach the fuel tank sender to the tank, so I only need to seal the    contact area between the sender unit face and the tank rib.   

From the various photos that I have seen, other builders have used    Proseal to leak proof the sender to the tank, and thus this appears    to be the way to go.   

Could anyone please confirm my assumptions regarding the application of    proseal to achieve a fuel/leak proof seal at this location, coupled with    confirming (or otherwise) the use of the supplied gasket.   

Your thoughts would be very much appreciated please.   

Regards   

Patrick, RV-10 #40299, South    Australia   

    

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patrick.pulis(at)seagas.c
Guest

Posted: Tue Jul 29, 2008 4:06 pm Post subject: Leak Proofing the Fuel Sender

dmasys(at)cox.net
Guest

Posted: Wed Jul 30, 2008 4:06 pm Post subject: Leak Proofing the Fuel Sender

Patrick,



By chance, I happen to have done the Van's service bulletin on my RV-7A last weekend that applies a safety wire to the fuel pickup in each tank.  To do this one has to remove the fuel tank access plates, which are essentially identical to the ones on the inboard tank rib of the RV-10.  I had done a little 'randomized' experiment by using Van's cork gasket on one side, sealed with ProSeal, and on the other side I just used ProSeal without any cork gasket, as was recommended by Gary Sobek, my Tech Counselor at the time.  The -7A is a bit over three years old, and here is what I can report:  both the ProSeal-only and the ProSeal-applied to cork gasket work fine to hold the fuel in the tank with no leaks.  Removing the side with the cork gasket was much easier, since the cork is soft and a putty knife can be slipped in between the pieces and the cover plate pried away and popped loose without much difficulty.  The ProSeal only side was quite a bit more difficult to break loose, and required sliding a single edge razor blade between the bonded surfaces most of the way around the circumference of the cover plate.  However, when it came loose it was somewhat easier to clean up using a razor blade as a scraper combined with MEK.  



So the decision to use a gasket or not really comes down to ease of future maintenance.  Either way keeps the fuel in the tank.



Hope this helps,

-Dan Masys

RV-10 N104LD back from OSH

RV-7A N747DL

patrick.pulis(at)seagas.c
Guest

Posted: Wed Jul 30, 2008 9:29 pm Post subject: Leak Proofing the Fuel Sender

Thanks Dan 



--

AV8ORJWC

Joined: 13 Jul 2006
Posts: 1149
Location: Aurora, Oregon "Home of VANS"

Posted: Sun Aug 03, 2008 4:33 pm Post subject: Leak Proofing the Fuel Sender

Not to attract contrarian comments but the use of metallic scrapers on aluminum might be best avoided.  We regularly complete such tasks with the use of MEK and plastic scrapers (and barrier gloves). Razor blades and putty knifes are a quick way to be pointed to the door on air carrier aircraft.  Your family members deserve no less.



FWIW



John C.



--

John Ackerman

Joined: 19 Jun 2006
Posts: 130
Location: Prescott, AZ

Posted: Sun Aug 03, 2008 9:03 pm Post subject: Leak Proofing the Fuel Sender

John, what is the reason given for no metallic scrapers? Crack  

initiation? Accidental cuts and gouges?

What do you do if you need something very thin as Dan did (see below)?

John Ackerman    40458



On Aug 3, 2008, at 5:25 PM, John Cox wrote:



 	  Quote: 	
		   



 Not to attract contrarian comments but the use of metallic scrapers  

 on aluminum might be best avoided.  We regularly complete such tasks  

 with the use of MEK and plastic scrapers (and barrier gloves). Razor  

 blades and putty knifes are a quick way to be pointed to the door on  

 air carrier aircraft.  Your family members deserve no less.



> .  Removing the side with the cork gasket was much easier, since  

> the cork is soft and a putty knife can be slipped in between the  

> pieces and the cover plate pried away and popped loose without much  

> difficulty.  The ProSeal only side was quite a bit more difficult  

> to break loose, !

> and required sliding a single edge razor blade between the bonded  

> surfaces most of the way around the circumference of the cover  

> plate.  However, when it came loose it was somewhat easier to clean  

> up using a razor blade as a scraper combined with MEK.

>

> So the decision to use a gasket or not really comes down to ease of  

> future maintenance.  Either way keeps the fuel in the tank.

>

> Hope this helps,

> -Dan Masys

> RV-10 N104LD back from OSH

> RV-7A N747DL

Kelly McMullen

Joined: 16 Apr 2008
Posts: 1188
Location: Sun Lakes AZ

Posted: Mon Aug 04, 2008 6:15 am Post subject: Leak Proofing the Fuel Sender

Same reason you don't use steel wool on aluminum. It can initiate

corrosion. Yes, steel scrapers will scratch the aluminum and can

generate all the issues of deep scratches.  Phenolic scrapers, or

scrap plexiglass ground into a scraper works pretty well.

I don't disagree with Dan using what he did for that purpose(getting

to skins apart), IF you recognize that close inspection will be

required and you may have to scrap a piece if it gets too scratched.

On way of reducing risk is to select stainless steel putty knife, to

minimize the corrosion aspect.

Of course John is giving you the airline point of view, where tanks

frequently need attention, and costs are much higher, as are risks,

along with the maximum level of regulation/oversight. Different

standards, different needs...but the physics of steel and aluminum

remain the same.



On Sun, Aug 3, 2008 at 9:58 PM, John Ackerman <johnag5b(at)cableone.net> wrote:

 	  Quote: 	
		   



 John, what is the reason given for no metallic scrapers? Crack initiation?

 Accidental cuts and gouges?

 What do you do if you need something very thin as Dan did (see below)?

 John Ackerman    40458



 On Aug 3, 2008, at 5:25 PM, John Cox wrote:



> 

>

> Not to attract contrarian comments but the use of metallic scrapers on

> aluminum might be best avoided.  We regularly complete such tasks with the

> use of MEK and plastic scrapers (and barrier gloves). Razor blades and putty

> knifes are a quick way to be pointed to the door on air carrier aircraft.

>  Your family members deserve no less.

>

>> .  Removing the side with the cork gasket was much easier, since the cork

>> is soft and a putty knife can be slipped in between the pieces and the cover

>> plate pried away and popped loose without much difficulty.  The ProSeal only

>> side was quite a bit more difficult to break loose, !

>> and required sliding a single edge razor blade between the bonded

>> surfaces most of the way around the circumference of the cover plate.

>>  However, when it came loose it was somewhat easier to clean up using a

>> razor blade as a scraper combined with MEK.

>>

>> So the decision to use a gasket or not really comes down to ease of

>> future maintenance.  Either way keeps the fuel in the tank.

>>

>> Hope this helps,

>> -Dan Masys

>> RV-10 N104LD back from OSH

>> RV-7A N747DL

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

AV8ORJWC

Joined: 13 Jul 2006
Posts: 1149
Location: Aurora, Oregon "Home of VANS"

Posted: Mon Aug 04, 2008 7:51 am Post subject: Leak Proofing the Fuel Sender

Let me add that we sneak Skin Knives into some applications (also a terminable offence).  Blending of scratches requires a 10:1 or 15:1 taper (depending on the SRM = Structural Repair Manual).  You all have written one to effect repairs, haven't you?  it is amazing how deep a scratch goes when force is used.  Remember that the Alclad pure coating is not very thick. Five percent on each side for a total of 10 percent coating.  So 0.032" means 0.0016" on each surface.  On the RV-12 using 0.020 skin it is even more critical.  Just hand force used on a tool can permanently stretch the skin - forever.



"Skin knives" and "thread taps" are two ways to get quickly busted.  We use them, on the sly and with high degree of situational awareness and desire for job security.



John - back to GRAVES tonight after two weeks with real aviators.



--

John Ackerman

Joined: 19 Jun 2006
Posts: 130
Location: Prescott, AZ

Posted: Tue Aug 05, 2008 9:30 am Post subject: Leak Proofing the Fuel Sender

Kelly, I wondered about that - certainly if particles of iron came off  

the scraper, it would be possible to form a corrosion cell, but a fair  

amount of material would be required to establish a significant  

corrosion rate. For heaven's sake don't ask me to quantify that!   

Steel wool is different - relatively large slivers do break off and  

lodge in the surface

More wondering ...

Is there a concern wherever steel meets aluminum? (answer, I think:  

"Of course, but Al forms a protective Al2O3 coating, limiting  

corrosion rate to an acceptable level except under really adverse  

circumstances")

Comment?

John



On Aug 4, 2008, at 7:12 AM, Kelly McMullen wrote:



 	  Quote: 	
		   



 Same reason you don't use steel wool on aluminum. It can initiate

 corrosion. Yes, steel scrapers will scratch the aluminum and can

 generate all the issues of deep scratches.  Phenolic scrapers, or

 scrap plexiglass ground into a scraper works pretty well.

 I don't disagree with Dan using what he did for that purpose(getting

 to skins apart), IF you recognize that close inspection will be

 required and you may have to scrap a piece if it gets too scratched.

 On way of reducing risk is to select stainless steel putty knife, to

 minimize the corrosion aspect.

 Of course John is giving you the airline point of view, where tanks

 frequently need attention, and costs are much higher, as are risks,

 along with the maximum level of regulation/oversight. Different

 standards, different needs...but the physics of steel and aluminum

 remain the same.



 On Sun, Aug 3, 2008 at 9:58 PM, John Ackerman  

 <johnag5b(at)cableone.net> wrote:

> 

> <johnag5b(at)cableone.net>

>

> John, what is the reason given for no metallic scrapers? Crack  

> initiation?

> Accidental cuts and gouges?

> What do you do if you need something very thin as Dan did (see  

> below)?

> John Ackerman    40458

>

> On Aug 3, 2008, at 5:25 PM, John Cox wrote:

>

>> 

>>

>> Not to attract contrarian comments but the use of metallic  

>> scrapers on

>> aluminum might be best avoided.  We regularly complete such tasks  

>> with the

>> use of MEK and plastic scrapers (and barrier gloves). Razor blades  

>> and putty

>> knifes are a quick way to be pointed to the door on air carrier  

>> aircraft.

>> Your family members deserve no less.

>>

>>> .  Removing the side with the cork gasket was much easier, since  

>>> the cork

>>> is soft and a putty knife can be slipped in between the pieces  

>>> and the cover

>>> plate pried away and popped loose without much difficulty.  The  

>>> ProSeal only

>>> side was quite a bit more difficult to break loose, !

>>> and required sliding a single edge razor blade between the bonded

>>> surfaces most of the way around the circumference of the cover  

>>> plate.

>>> However, when it came loose it was somewhat easier to clean up  

>>> using a

>>> razor blade as a scraper combined with MEK.

>>>

>>> So the decision to use a gasket or not really comes down to ease of

>>> future maintenance.  Either way keeps the fuel in the tank.

>>>

>>> Hope this helps,

>>> -Dan Masys

>>> RV-10 N104LD back from OSH

>>> RV-7A N747DL

>

John Ackerman

Joined: 19 Jun 2006
Posts: 130
Location: Prescott, AZ

Posted: Tue Aug 05, 2008 9:35 am Post subject: Leak Proofing the Fuel Sender

Scratches, John:

Everything in this non-ideal world gets scratched. I believe the issue  

is what are the stresses on the part, how big is the scratch, and how  

sharp are its corners. I certainly don't disagree with what you say,  

and your post is very helpful. Do you have any more quantitative  

guidance for us? It would be most welcome.

John  Ackerman   40458



On Aug 4, 2008, at 8:49 AM, John Cox wrote:



[quote] 



 Let me add that we sneak Skin Knives into some applications (also a  

 terminable offence).  Blending of scratches requires a 10:1 or 15:1  

 taper (depending on the SRM = Structural Repair Manual).  You all  

 have written one to effect repairs, haven't you?  it is amazing how  

 deep a scratch goes when force is used.  Remember that the Alclad  

 pure coating is not very thick. Five percent on each side for a  

 total of 10 percent coating.  So 0.032" means 0.0016" on each  

 surface.  On the RV-12 using 0.020 skin it is even more critical.   

 Just hand force used on a tool can permanently stretch the skin -  

 forever.



 "Skin knives" and "thread taps" are two ways to get quickly busted.   

 We use them, on the sly and with high degree of situational  

 awareness and desire for job security.



 John - back to GRAVES tonight after two weeks with real aviators.



 --

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