X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from m12.lax.untd.com ([64.136.30.75] verified) by logan.com (CommuniGate Pro SMTP 5.1c.2) with SMTP id 1333906 for flyrotary@lancaironline.net; Wed, 02 Aug 2006 14:40:27 -0400 Received-SPF: pass receiver=logan.com; client-ip=64.136.30.75; envelope-from=alwick@juno.com Received: from m12.lax.untd.com (localhost [127.0.0.1]) by m12.lax.untd.com with SMTP id AABCPB6MGAD8Z6C2 for (sender ); Wed, 2 Aug 2006 11:39:34 -0700 (PDT) X-UNTD-OriginStamp: L941HVjjYzDhN3itp//mkGejFezEGpfdSE6vOztl0P8MzDChCNDC7w== Received: (from alwick@juno.com) by m12.lax.untd.com (jqueuemail) id LWSRXTSC; Wed, 02 Aug 2006 11:38:45 PDT To: flyrotary@lancaironline.net Date: Wed, 2 Aug 2006 11:07:41 -0700 Subject: Re: [FlyRotary] Re: Auto Fuel - composite tanks Message-ID: <20060802.113833.3936.4.alwick@juno.com> X-Mailer: Juno 5.0.33 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary=--__JNP_000_6095.6391.4c99 X-Juno-Line-Breaks: 8-6,9-10,13,15-16,19-20,23-33,35-36,39,43-44,46,55,59,62,65,69-74,76,79-80,84-85,91,95,99,104-105,109-110,112-113,117-132,133-32767 From: al p wick X-ContentStamp: 7:3:2591488582 X-MAIL-INFO:3debeb1bceb37ffee7472f1b672f23da0b9ea32f8b8ac35bce8ba39e8b3e8b6e27e31ec7eb5f1bae1b8ece5723776f57feb38fe3eaf3d71bbfe323433b833bbf9b8b8f83bb635aa7bb X-UNTD-Peer-Info: 127.0.0.1|localhost|m12.lax.untd.com|alwick@juno.com This message is in MIME format. Since your mail reader does not understand this format, some or all of this message may not be legible. ----__JNP_000_6095.6391.4c99 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: 8bit Point to consider. The little squiggling,vibrating, pressure changes the plane sees can easily cause a micro hole to develop where none showed in static tests. Not uncommon to have leak develop a year later with avgas. Weave showing may be fuel sensitive paint,primer, or filler. Not epoxy or other component. I used a paint that was fuel sensitive. Had similar symptoms. When I sealed the leak, the paint returned to normal. I tested all of the foams near tank, glass, epoxy. None fuel sensitive. So, yes, I too have that foam sandwich. I noticed pattern to surface symptoms. That's how I selected locations to drill. Drilling into outer skin allowed fuel to dribble out. Epoxy cured fine apparently, as I no longer have leaks. Just offering my test results and findings. I SUSPECT your issues have nothing to do with fuel type (except plastic fuel gauge). Lot's of evidence supports my theory, but not conclusive. -al wick Artificial intelligence in cockpit, Cozy IV powered by stock Subaru 2.5 N9032U 200+ hours on engine/airframe from Portland, Oregon Prop construct, Subaru install, Risk assessment, Glass panel design info: http://www.maddyhome.com/canardpages/pages/alwick/index.html On Tue, 1 Aug 2006 17:49:07 -0700 "Al Gietzen" writes: If you read the archives from canard builders you will find it's extremely common to have such pinhole leaks. If I had to guess, I'd say 50% have this problem. Regardless of type of fuel I agree that could well be that the leak in the bottom strake inner skin has been there and has nothing to do with the type of fuel. I had leak tested with air after strake closure, and it held about an 8 – 10” head of water pressure for days. If you had any mushiness near leaks, then I'd be concerned. I tested non-compatible epoxy and it just gradually got mushy. What I have now is a roughly oval area about 6” by 4” where the weave of the glass cloth is showing through the paint finish, and it feels/looks like there maybe some dis-bonding of the outer skin from the foam. My guess is that somewhere in that area there is a pinhole leak in the inner skin, and the fuel has permeated the foam. There is no fuel leak on the outside. Because of the roughness/weave showing, and the dis-bonding, it seems clear that the fuel (or something) is doing something to the epoxy. It was my understanding that fuel (avgas, I suppose) would not permeate the closed cell PVC foam, and not effect the epoxy. I drained tank, then drill 1/16" hole at leak location. Hole only goes part way into tank wall. Fuel came burbling out. I then used syringe with no needle to inject epoxy. Totally solved problem, no leaks for years now. Do you also have a foam core sandwich tank wall? How did you decide where to drill the outer skin? What epoxy did you use; I’d think the presence of fuel would mess up the epoxy before it cured? Leaks take a long time to show on surface, fuel has to migrate from interior hole to exterior hole. That also makes it tough to find leak source. I’ve drained the fuel on that side, and for now I’m leaving it as is since we are trying to get first flight done Friday/Saturday. I’ll probably put some avgas in on that side for balance, and deal with the apparent leak later. Thanks, Al On Mon, 31 Jul 2006 10:14:58 -0700 "Al Gietzen" writes: Not sure where to go with this because there are only a few here with epoxy fuel tanks, and on the Velocity list very few interested in the use of mogas. I’m suspecting fuel compatibility isses. I first put fuel in the tanks nearly 2 years ago and used Chevron regular. Everything was fine. When I moved the plane to the airport 3 months ago (tanks empty) I filled with Exxon-Mobile. Four troubling things have come up in the past few weeks. 1. I have Vance Atkinson site gauge that has a white plastic back plate for easier reading of the fuel level. The small hole through the backing has been swelling shut so the sight gauge no longer works. I contacted Vance who said that there are hundreds of these gauges in EZs using mogas without problems, but he has had 3 incidents like mine in the last three months. 2. A couple of weeks ago there was suddenly a pinhole leak in one of the gear well enclosures. These enclosures are part of the fuel tank wall, and are parts that come with the Velocity kit. These are also made and coated with EZ-poxy. 3. Looking in through the filler cap I see reddish-purple splotches and streaks on those gear leg enclosures. Poking and scratching with some safety wire on a stick does not indicate any softness of the surface. 4. Yesterday, under the leading edges of one of the strakes, I noted an area with some slight surface irregularity. Pushing on it suggests some sponginess. This is ½” foam core material, and indicates the possibility of a pinhole leak in the inner skin, and fuel softening the PVC foam. PVC foam is supposed to be unaffected by fuel. My tanks (strakes) were made and coated with EZ-poxy back in 1998. At the time I polled EZ flyers about there experience, and talked to reps of various epoxy manufacturers about auto fuel compatibility. All the evidence said go with the EZ-poxy. Any others with composite tanks having any trouble? Anybody using Exxon-mobile fuel? Know of any new additives that are an issue? I’m thinking I should drain this fuel ASAP, but then what? Other brand? That expensive Avgas? Regardless I may be faced with cutting open a strake at some point, but right now we are trying to get first flight done this coming weekend. -al wick Artificial intelligence in cockpit, Cozy IV powered by stock Subaru 2.5 N9032U 200+ hours on engine/airframe from Portland, Oregon Prop construct, Subaru install, Risk assessment, Glass panel design info: http://www.maddyhome.com/canardpages/pages/alwick/index.html -al wick Artificial intelligence in cockpit, Cozy IV powered by stock Subaru 2.5 N9032U 200+ hours on engine/airframe from Portland, Oregon Prop construct, Subaru install, Risk assessment, Glass panel design info: http://www.maddyhome.com/canardpages/pages/alwick/index.html ----__JNP_000_6095.6391.4c99 Content-Type: text/html; charset=iso-8859-1 Content-Transfer-Encoding: quoted-printable
Point to consider. The little squiggling,vibrating, pressure=20 changes the plane sees can easily cause a micro hole to develop where = none=20 showed in static tests. Not uncommon to have leak develop a year later with= =20 avgas.
 
Weave showing may be fuel sensitive paint,primer, or filler. Not epoxy= or=20 other component. I used a paint that was fuel sensitive. Had similar = symptoms.=20 When I sealed the leak, the paint returned to normal.
I tested all of the foams near tank, glass, epoxy. None fuel sensitive= . So,=20 yes, I too have that foam sandwich.
 
I noticed pattern to surface symptoms. That's how I selected locations= to=20 drill. Drilling into outer skin allowed fuel to dribble out. Epoxy cured = fine=20 apparently, as I no longer have leaks.
 
Just offering my test results and findings. I SUSPECT your issues = ;=20 have nothing to do with fuel type (except plastic fuel gauge). Lot's of = evidence=20 supports my theory, but not conclusive.
 

-al wick
Artificial intelligence in cockpit, Cozy IV powered by= =20 stock Subaru 2.5
N9032U 200+ hours on engine/airframe from Portland,=20 Oregon
Prop construct, Subaru install, Risk assessment, Glass panel = design=20 info:
http:= //www.maddyhome.com/canardpages/pages/alwick/index.html
 
 
On Tue, 1 Aug 2006 17:49:07 -0700 "Al Gietzen" <ALVentures@cox.net> writes:

 

If you read the archives from = canard=20 builders you will find it's extremely common to have such pinhole leaks. = If I=20 had to guess, I'd say 50% have this problem. Regardless of type of=20 fuel

I agree that= could=20 well be that the leak in the bottom strake inner skin has been there and = has=20 nothing to do with the type of fuel.  I had leak tested with air = after=20 strake closure, and it held about an 8 =96 10=94 head of water pressure = for=20 days.

 

If you had any mushiness near = leaks, then=20 I'd be concerned. I tested non-compatible epoxy and it just gradually got= =20 mushy.

What I have = now is=20 a roughly oval area about 6=94 by 4=94 where the weave of the glass cloth= is=20 showing through the paint finish, and it feels/looks like there maybe = some=20 dis-bonding of the outer skin from the foam. My guess is that somewhere = in=20 that area there is a pinhole leak in the inner skin, and the fuel has=20 permeated the foam.  There is no fuel leak on the outside.  = Because=20 of the roughness/weave showing, and the dis-bonding, it seems clear that = the=20 fuel (or something) is doing something to the epoxy.  It was my=20 understanding that fuel (avgas, I suppose) would not permeate the closed = cell=20 PVC foam, and not effect the epoxy.

<= SPAN=20 style=3D"FONT-SIZE: 12pt">I drained tank, then drill 1/16" hole at leak=20 location. Hole only goes part way into tank wall. Fuel came burbling out.= I=20 then used syringe with no needle to inject epoxy. Totally solved problem,= no=20 leaks for years now.

Do you also = have a=20 foam core sandwich tank wall?  How did you decide where to drill the= =20 outer skin?  What epoxy did you use; I=92d think the presence of = fuel would=20 mess up the epoxy before it cured?

<= SPAN=20 style=3D"FONT-SIZE: 12pt">Leaks take a long time to show on surface, fuel= has to=20 migrate from interior hole to exterior hole. That also makes it tough to = find=20 leak source.

I=92ve = drained the=20 fuel on that side, and for now I=92m leaving it as is since we are trying= to get=20 first flight done Friday/Saturday.  I=92ll probably put some avgas = in on=20 that side for balance, and deal with the apparent leak=20 later.

Thanks,

Al

<= SPAN=20 style=3D"FONT-SIZE: 12pt"> 

<= SPAN=20 style=3D"FONT-SIZE: 12pt"> 

 

On Mon, 31 Jul = 2006=20 10:14:58 -0700 "Al Gietzen" <ALVentures@cox.net> writes:

=

Not sure= where to=20 go with this because there are only a few here with epoxy fuel tanks, = and on=20 the Velocity list very few interested in the use of mogas.  I=92m= =20 suspecting fuel compatibility isses.

 

I first = put fuel=20 in the tanks nearly 2 years ago and used Chevron regular. Everything = was=20 fine.  When I moved the plane to the airport 3 months ago (tanks = empty)=20 I filled with Exxon-Mobile.  Four troubling things have come up in= the=20 past few weeks.

 

<= FONT=20 face=3D"Times New Roman" size=3D3>1.<= FONT=20 face=3D"Times New Roman" size=3D1>    =20 I have Vance Atkinson = site=20 gauge that has a white plastic back plate for easier reading of the = fuel=20 level. The small hole through the backing has been swelling shut so the= =20 sight gauge no longer works. I contacted Vance who said that there are= =20 hundreds of these gauges in EZs using mogas without problems, but he = has had=20 3 incidents like mine in the last three months.

<= FONT=20 face=3D"Times New Roman" size=3D3>2.<= FONT=20 face=3D"Times New Roman" size=3D1>    =20 A couple of weeks ago = there=20 was suddenly a pinhole leak in one of the gear well enclosures.  = These=20 enclosures are part of the fuel tank wall, and are parts that come with= the=20 Velocity kit.  These are also made and coated with=20 EZ-poxy.

<= FONT=20 face=3D"Times New Roman" size=3D3>3.<= FONT=20 face=3D"Times New Roman" size=3D1>    =20 Looking in through the = filler=20 cap I see reddish-purple splotches and streaks on those gear leg=20 enclosures.  Poking and scratching with some safety wire on a = stick=20 does not indicate any softness of the surface.

<= FONT=20 face=3D"Times New Roman" size=3D3>4.<= FONT=20 face=3D"Times New Roman" size=3D1>    =20 Yesterday, under the = leading=20 edges of one of the strakes, I noted an area with some slight surface=20 irregularity.  Pushing on it suggests some sponginess.  This = is =BD=94=20 foam core material, and indicates the possibility of a pinhole leak in = the=20 inner skin, and fuel softening the PVC foam.  PVC foam is supposed= to=20 be unaffected by fuel.

 

My tanks= =20 (strakes) were made and coated with EZ-poxy back in 1998.  At the = time=20 I polled EZ flyers about there experience, and talked to reps of = various=20 epoxy manufacturers about auto fuel compatibility.  All the = evidence=20 said go with the EZ-poxy.

 

Any = others with=20 composite tanks having any trouble?  Anybody using Exxon-mobile = fuel?=20  Know of any new additives that are an issue?

 

I=92m = thinking I=20 should drain this fuel ASAP, but then what?  Other brand?  = That=20 expensive Avgas?  Regardless I may be faced with cutting open a = strake=20 at some point, but right now we are trying to get first flight done = this=20 coming weekend.

 

 

 


-al wick
Artificial = intelligence=20 in cockpit, Cozy IV powered by stock Subaru 2.5
N9032U 200+ hours on=20 engine/airframe from Portland, Oregon
Prop construct, = Subaru=20 install, Risk assessment, Glass panel design=20 info:
http://www.maddyhome.com/canardpages/pages/alwick/index.html

=
 

-al wick
Artificial intelligence in= =20 cockpit, Cozy IV powered by stock Subaru 2.5
N9032U 200+ hours on=20 engine/airframe from Portland, Oregon
Prop construct, Subaru install, = Risk=20 assessment, Glass panel design=20 info:
http://www.maddyhome.com/canardpages/pages/alwick/index.html
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