REFLECTOR: Jeffco Problem...worst day as a builder
Chuck
c.harbert1 at verizon.net
Thu Aug 14 10:13:28 CDT 2008
Guys, I didn't use Jeffco, but it sure does appear to be a bonding issue as
you've surmised. Have you tried to chip it off to see what the base epoxy
looks like? Maybe you could salvage the strakes if you could remove the
Jeffco (chip/sand down to bare glass and recoat). I used a mixture of EZpoxy
and cabo to seal my tanks. Never has leaked and had regular gas in them when
I had the Mazda rotary for a couple yrs.
Chuck
----- Original Message -----
From: "Andy Millin" <amillin at sbcglobal.net>
To: "'Velocity Aircraft Owners and Builders list'" <reflector at tvbf.org>
Sent: Wednesday, August 13, 2008 6:08 AM
Subject: Re: REFLECTOR: Jeffco Problem...worst day as a builder
> Dave,
>
> There have been a few cases where the tanks held pressure after
> construction. Then after the engine run, leaks appeared. Possibly a
> crack
> produced from the vibration.
>
> To test Bruce's hypothesis, you might take a piece of the strake (as
> removed) with the EZ-84 exposed and soak the thing in the fuel you were
> using. Give it a week or so and see if it softens.
>
> Andy
>
> -----Original Message-----
> From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On
> Behalf Of David Staten
> Sent: 08-12-2008 4:20
> To: Velocity Aircraft Owners and Builders list
> Subject: Re: REFLECTOR: Jeffco Problem...worst day as a builder
>
> When chris and I first sealed the fuel system it held balloon pressure,
> so it led us to believe there were no leaks
>
> Dave
>
> bdtopp at comcast.net wrote:
>> Chris,
>>
>> Sorry to hear about your problem. It was mentioned earlier (forgot
>> who responded to your email) that maybe the material the Jeffco bonded
>> to failed instead of the Jeffco itself failing. There is evidence of
>> this by the yellow discoloration on the Jeffco chips. Here is a
>> possible senerio to think about when trying to figure this out.
>> When you originally built the strakes and coated with Jeffco, there
>> was a small leak somewhere. This allowed a very small amount of auto
>> fuel to leak into the foam. The auto fuel started to slowly break
>> down the EZ84 underneath the Jeffco. This may of continued to leak
>> which in turn caused more leaks as the Jeffco broke down and chipped
>> away. In other words, it deteriated over time getting worse and worse.
>> Maybe it wasn't the Jeffco that originally failed? Something to
>> think about anyways. Good luck with your repair.
>>
>> Bruce Topp
>>
>>
>> -------------- Original message --------------
>> From: "Christopher Barber" <CBarber at texasattorney.net>
>> Well, this was the worst builder day I have had. That includes the
>> day I realized I had to build a new rotary engine, which, btw, was
>> running better each day before this fuel issue developed.
>>
>> As the collective from the various list I am on may recall, I have
>> had persistent fuel leak issues. A few weeks ago I had a visit
>> from the fine men of the Ellington/JSC/NASA fire department when I
>> leaked a few gallons on to the hangar floor while I was at home
>> sleeping late. Also, I thought my original clear factory tubes
>> failed due to ethanol. They had turned color and became brittle
>> (turns out they had not YET leaked.
>>
>> I tried sucking new Jeffco into where I thought the leak was (very
>> hard to reach area behind the spar. I found a loose hard point and
>> since I was having some fuel seep through the floor of my cabin I
>> thought maybe the fuel was seeping in behind the hard point into
>> the foam to the cabin floor. Since the two hard points from the
>> strake fuel line were bot! h put i n per plans years ago (before
>> my choice to use a rotary, thus auto fuel) they were installed
>> with EZ-84/flox. Since the flox around the loose hard point seemed
>> a bit "off" I decided to redo both of them with Jeffco. At the
>> same time I also took out the factory fuel elbow fittings as
>> mentioned above and installed Vance Atkinson's gages. I did this
>> over the last few days.
>>
>> I thought all was well, but when I added fuel to the right strake
>> only, I still had fuel seeping through the cabin floor. So, I am
>> having fuel leak though the inner foam. I spoke with Velocity, Inc
>> who stated I could either go into the inner skin around the stake
>> storage area or cut a hole in the top of the strake to find the
>> leak. I chose to go into the top of the strake as I thought it
>> would be better to not try to patch a leak from the outside. So, I
>> cut a hole in the strake to apply Jeffco to try to find/cure the
>> leak.
>>
>> EEEEEEAAAAAKKKKK. I opened up the top right strake and the Jeffco
>> on the! top of the strake was sitting in the bottom of the tank.
>> OMG!!!!. Almost all the Jeffco from the top of the strake had
>> fallen off. It was all flaky and not adhering. Also, a number of
>> places from the sides and bottom had also fallen off.
>>
>> I called Velocity, Inc and they said they had never had this issue
>> before. They suggested I look in the other stake to see if the
>> problem was there too. We discussed when I applied it and how. Now
>> guys and gals, I am not a complete incompetent. I know I sanded
>> stakes before I applied the Jeffco, I mixed it well and per
>> instructions. Also, the top strake Jeffco was applied at a
>> different time/batch from the sides/bottom. The Velocity top
>> strake is a pre-built piece and is laid on the strake sides/bottom
>> in a separate step and the Jeffco is applied to the top before you
>> seal it, then you seal it with more Jeffco.
>>
>> I have never had more than about 20 gallons of fuel in the system
>> (about 60 total capacity). I have had the fuel sit in the !
>> strakes for a long while though. I used the Jeffco since it is
>> supposed to be more resistant to fuels like diesel and auto, even
>> with ethanol...at least that was my understanding. Some ares of
>> the strakes seem pretty good (but I don't trust any of it now). I
>> did get TWO, one gallon kits of Jeffco back when I did this part
>> of the build. My first thought is that perhaps one of the buckets
>> was a bad batch. Donno.
>>
>> I did cut into the pilot strake too. It was not as bad. The top of
>> the strake looks good, but I do have some flaking on the sides.
>> There are four compartments in each strake. I cut into one on the
>> co-pilot side, and three on the pilot side so far. One on the
>> pilot side seems perfect (so far). The inconsistency has me
>> confused currently. But to be honest, after dealing with this for
>> a while and trying to be philosophical about it...such as I would
>> much rather find it now, I walked away and worked on re-attaching
>> my ailerons after balancing them.
>>
>> So, it seems many of those other fuel issue may have not been the
>> problem I thought they were....this does seem to be the cause for
>> when the fire department came out as that leak just seem to
>> happen. When I pressure tested this system a few years back, all
>> seemed fine.
>>
>> I am posting the pix on the Canardzone but I am posting this
>> message on a few sites like FlyRotary and the Velocity Builders
>> site. The factory asked me to post too so they could have a look
>> and determine if this may be a isolated incident (such as me
>> missing something big) OR if it could be a bigger problem. Well,
>> here are some of the pix I took....if they are blurry, don't
>> worry, it is only my tears......
>>
>> The link to pictures is
>>
> http://www.canardzone.com/forum/showthread.php?p=25569&posted=1#post25569
>>
> <http://www.canardzone.com/forum/showthread.php?p=25569&posted=1#post25569>
>>
>> All the best,
>>
>> Chris
>>
>>
>> ------------------------------------------------------------------------
>>
>> Subject:
>> REFLECTOR: Jeffco Problem...worst day as a builder
>> From:
>> "Christopher Barber" <CBarber at texasattorney.net>
>> Date:
>> Tue, 12 Aug 2008 02:33:46 +0000
>> To:
>> "Velocity Aircraft Owners and Builders list" <reflector at tvbf.org>,
>> "FlyRotary aircraft" <flyrotary at lancaironline.net>,
>> <canard-aviators at yahoogroups.com>
>>
>> To:
>> "Velocity Aircraft Owners and Builders list" <reflector at tvbf.org>,
>> "FlyRotary aircraft" <flyrotary at lancaironline.net>,
>> <canard-aviators at yahoogroups.com>
>>
>>
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