REFLECTOR: Jeffco Problem...worst day as a builder

Laurence Coen lwcoen at hotmail.com
Wed Aug 13 10:52:36 CDT 2008


Chris,

I think the first thing to look at to find the real problem is the fact that there are hundreds of flying planes that have non leaking tanks with internal coatings of EZ-84 or Jeffco  exposed to both 100LL and auto fuel.  Even if the Jeffco didn't bond well to the EZ-84 it should still remain intact and act like a bladder in an aluminum tank. The fact that it cracked up and seemed to curl would make me think that the Jeffco was somehow contaminated.  It could be something as simple as a wax costing on the container you mixed the Jeffco in or perhaps something used to clean the strakes prior to the application.  In any event I would take the suggestion that you completely replace the strakes very seriously. 

Larry Coen
N136LC


From: Christopher Barber 
Sent: Monday, August 11, 2008 9:28 PM
To: Velocity Aircraft Owners and Builders list ; FlyRotary aircraft ; canard-aviators at yahoogroups.com 
Subject: REFLECTOR: Jeffco Problem...worst day as a builder


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 both put in 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

All the best,

Chris


--------------------------------------------------------------------------------


_______________________________________________
To change your email address, visit http://www.tvbf.org/mailman/listinfo/reflector

Visit the gallery!  www.tvbf.org/gallery
user:pw = tvbf:jamaicangoose
Check new archives: www.tvbf.org/pipermail
Check old archives: http://www.tvbf.org/archives/velocity/maillist.html
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://www.tvbf.org/mailman/private/reflector/attachments/20080813/4b93383a/attachment-0001.htm 


More information about the Reflector mailing list