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Hi Lynn,
As I have discussed a bit on various sites, there was even a write up about
it in an issue of Contact Magazine a short while back, the Jeffco I used peeled
off. I built the strakes at different times in my garage but had the
Jeffco flake off in both strakes. However, the sump, built at even a
different time was perfect with no issue with Jeffco. I am certain I
sanded/prepped properly but the problem will likely remain a mystery. I
did send a sample of my failure and they are as baffled as I. I have not
yet sent any to the new owners of Jeffco.
WELL, to eliminate the Jeffco as an issue I rebuilt the strake interior
skins with EZPoxy and bid. As I have stated, I used the Jeffco
to help ensure resistance to various fuel types...such as Diesel and/or fuel
additives.. I considered the Detlahawk back in the day before I chose
the Mazda rotary.
Anyway, I cut the top sections off each tank section leaving a lip on
each so as to be able to set repaired pieces into the cutout later. I
laboriously sanded and ground out the old Jeffco from the inner walls. I
cut out a couple of inner walls completely to determine if that may be an easier
process. I determined It was better to remove the bad product instead of
removing the entire wall. I figured if I only sanded the stuff off, even
if I got too aggressive in places it was easier to repair the small area,
especially since I was going to be adding new layers of glass throughout then
entire tank area. This also allowed me to feel better about the structural
integrity of the strake walls and baffles. I still am uncertain how much
the baffles add to the integrity of the strake/wing as to flexing etc, but
I figured I did not want to worry about it. I have wondered about removing
all the baffles and just install an aluminum tank with aluminum baffles in
the new tank shell.....but that will hopefully remain only an idle
speculation.
So, after grinding off the Jeffco, I laid in new bid throughout the tanks
with heavy applications of EZPoxy. I spoke to Velocity who told me they
started using Jeffco more to address issues that had NOT ever presented
themselves, but to minimize the concerns of customers. They had not
experienced problems with EZ10/EZ83 in tank applications even with ethanol added
in auto fuels. IIRC, as I mentioned here before, Velocity has a customer
who builds motorcycle fuel tanks out of fiberglass. This customer did some
research who determined that EZPoxy turned out to be the better/best epoxy to
use with Auto fuel.
I tested the repairs before I replaced the strake top sections with
water. I filled the strakes with water and let it sit overnight.
Everything held. Put the nose several feet in the air and the water did
not leak.
I also repaired the sections I cut out of the strake tops by grinding off
the Jeffco and adding new/additional glass. I added more lip area around
all the cut openings so the cut out pieces to sit on. Once all was
prepared, I did a heavy flox application on the lips and placed the tops on top
of the lips, weighted it all down and crossed my fingers. Well, the pilot
side sealed completely (yeah, it was the side I cut up second, thus my process
had improves....hey, if ever there is a second plane built it will certainly be
twice as good in half the time <g>),the copilot side took a bit of leak
searching. I put a balloon over the vent outlet and blew compressed air
into the fuel outlet while spraying soapy water over the repaired area. WOW,
some of the leaks were huge. How did that happen. Oh well. I
cut the outer skin off until I found the leak, repaired the area and after about
two days of the process was finally able to get both sides to hold
air.
Once the balloons stayed full I went to making the tops look pretty by
adding blue foam where I had to be more aggressive on the outer skin repair,
applied micro to seal seams etc and laid down new glass over the entire
area. A few days ago I applied micro and last night I calibrated the fuel
gauges to 25 gallons and started the engine briefly. I have some pix of
the process that I will likely post on CanardZone and place link here for the
curious.
You had to ask a person willing to share the gory details <g>
So, build on.......
All the best,
Chris
----- Original Message -----
Sent: Sunday, December 07, 2008
Subject: [FlyRotary] Re: TX Rotary
Velocity update
As
y'all likely remember I had to redo my strakes following finding my Jeffco
fuel tank sealant had failed a few months ago. A few days ago I applied some
micro on my hopefully now repaired strakes. I still have to smooth and
pretty up the micro, but to get away from the fiberglass work for a bit I
decided to add fuel to my new strake tanks and calibrate my newly installed
Atkinson fuel gages.
I had about 25 gallons that I added one gallon
at a time, 1/2 gallon to each side. The Velocity has a center sump tank that
the two strake tanks dump into. So I added fuel to each side in
approximately equal amounts to allow everything to equalize better. I filled
the sump tank first and it took just under five gallons. Nothing seemed to
leak confirming my air pressure test with balloons a while
back.
What method, materials did you use to repair your fuel tanks. You cannot
be the only one having this problem.
Thank you.
Lynn E. Hanover
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