Sealant for polyethylene fuel tank?

"d.l.anderson" wrote in message
...

Here's a link to a Kitfox builders site. It's not my site, but it has good
pictures of the exact same header tank itself:
http://www.scoobysworkshop.com/2005p...tors_small.jpg
http://www.scoobysworkshop.com/2005p...Done_small.jpg

There's no real build up, but the tank has thick enough walls to allow a
bit
of thread. There's no openings to allow nuts to go in, meaning that viton
ring approach is practically rules out. The guy that made the pictures has
used some kind of kit or glue to bond the brass inserts into the tank, and
it's this kit that eventually gives way and develops leaks. We got the
tank
from a previous owner who was honest enough to tell us about the problem
beforehand and we're trying to solve this in a reliable way.

Rob


OK, bigger pictures at:
http://www.scoobysworkshop.com/2005p...Connectors.jpg
http://www.scoobysworkshop.com/2005p...erTankDone.jpg

Hmmm, looks like no bosses...just threaded into the tank with a sealer
and cinched up with a nut. Is there also a pickup screen on the
inside of the tank, connected to the AN angle fitting? How about a
low point quick drain? Might be a good idea.

You could use a hole saw to cut an access hole that could later be
closed using an expanding, fuel resistant "Thermos style" pressure
cap. Four different sizes at Wicks Aircraft. The 2" TURN-TITE FUEL
CAP looks to be the most secure.
http://www.wicksaircraft.com/catalog...301/index.html
Then you could fish a straight AN bulkhead fitting like this:
http://www.wicksaircraft.com/catalog...955/index.html
with an O-ring on it down a wire and pull it out far enough to get a
bulkhead nut on it.

You should provide some means of inspecting or cleaning out the inside
of the tank anyway.

D.Anderson

Good advice, thanks everyone!

The tank already has a low point drain connection which attached to a drain
valve. Construction is the same brass insert. There's no pickup screen on
the AN fitting, it's again the same brass insert with a standard AN
connection screwed in.

As you can (barely) tell from the picture, there's also two connections on
the righthand side. The top one is unused. The bottom one fits a 'low fuel'
level detector. Plenty of holes, but none large enough to do much fishing.
Anyway, I have plenty of options to explore from this thread, thanks again
everyone.

Rob

"d.l.anderson" wrote

Hmmm, looks like no bosses...just threaded into the tank with a sealer
and cinched up with a nut. Is there also a pickup screen on the
inside of the tank, connected to the AN angle fitting? How about a
low point quick drain? Might be a good idea.

You could use a hole saw to cut an access hole that could later be
closed using an expanding, fuel resistant "Thermos style" pressure
cap. Four different sizes at Wicks Aircraft. The 2" TURN-TITE FUEL
CAP looks to be the most secure.
http://www.wicksaircraft.com/catalog...301/index.html
Then you could fish a straight AN bulkhead fitting like this:
http://www.wicksaircraft.com/catalog...955/index.html
with an O-ring on it down a wire and pull it out far enough to get a
bulkhead nut on it.

You should provide some means of inspecting or cleaning out the inside
of the tank anyway.


I agree with everything in this post. No drain, no inspection plate or cap?
Not my ideal setup, I think.

Also, depending on sealants on threads (in the thin walls of a tank) to keep
fuel from leaking into the cockpit....Gives me the "willies."

Get a way to put compression fittings inside the tank, or install a boss
with plastic welding, or something.

A fire in a cockpit would be one of the most terrible ways to die that I
could think of.
--
Jim in NC

"d.l.anderson" wrote in message
...

...
You could use a hole saw to cut an access hole that could later be
closed using an expanding, fuel resistant "Thermos style" pressure
cap. Four different sizes at Wicks Aircraft. The 2" TURN-TITE FUEL
CAP looks to be the most secure.
http://www.wicksaircraft.com/catalog...301/index.html

I watched two people burn to death in front of the airshow crowd at Oshkosh
20 some years ago when this type of fuel cap popped off after a T-18 hit the
ground inverted. The occupants survived the impact and were pleading for
help on the radio. Unfortunatly, the aircraft was sitting in a big puddle of
burning fuel and no one could get to them. By the time the fire trucks
arrived, they were dead.

This style of fuel cap falls into my "not recommended" catagory.

--
Geoff
The Sea Hawk at Wow Way d0t Com
remove spaces and make the obvious substitutions to reply by mail
When immigration is outlawed, only outlaws will immigrate.

"Capt. Geoffrey Thorpe" wrote

I watched two people burn to death in front of the airshow crowd at
Oshkosh 20 some years ago when this type of fuel cap popped off after a
T-18 hit the ground inverted. The occupants survived the impact and were
pleading for help on the radio. Unfortunatly, the aircraft was sitting in
a big puddle of burning fuel and no one could get to them. By the time the
fire trucks arrived, they were dead.

This style of fuel cap falls into my "not recommended" catagory.

Wow, rough way to go. I would have to agree with you.

I would think that a fitting threaded into less than 1/8" of plastic would
fall into the same type of danger category. They could blow out, or be
pushed out, with a minimum of effort, not to mention the current problem of
leakage.

An inspection and access hole could be made so easily, and a plate of
aluminum and gasket with a backing plate (or ring) to screw into could be
done so easily, I would think that would be the first choice. Then, a
fitting with a true nut and O-ring could be used on all of the fittings,
with security, and no problems with leaks.

How much effort could that be, for containing gas in the same area that you
are sitting? I would call that a no-brainer.
--
Jim in NC

On Sun, 4 Mar 2007 21:19:37 -0500, "Morgans"
wrote:


"Capt. Geoffrey Thorpe" wrote

I watched two people burn to death in front of the airshow crowd at
Oshkosh 20 some years ago when this type of fuel cap popped off after a
T-18 hit the ground inverted. The occupants survived the impact and were
pleading for help on the radio. Unfortunatly, the aircraft was sitting in
a big puddle of burning fuel and no one could get to them. By the time the
fire trucks arrived, they were dead.

This style of fuel cap falls into my "not recommended" catagory.

Wow, rough way to go. I would have to agree with you.

I would think that a fitting threaded into less than 1/8" of plastic would
fall into the same type of danger category. They could blow out, or be
pushed out, with a minimum of effort, not to mention the current problem of
leakage.

An inspection and access hole could be made so easily, and a plate of
aluminum and gasket with a backing plate (or ring) to screw into could be
done so easily, I would think that would be the first choice. Then, a
fitting with a true nut and O-ring could be used on all of the fittings,
with security, and no problems with leaks.

How much effort could that be, for containing gas in the same area that you
are sitting? I would call that a no-brainer.


A no-brainer is a "dip tube" fuel outlet, where the fitting goes in
the TOP of the tank. Only caveat is you need a fuel pump.

--
Posted via a free Usenet account from http://www.teranews.com

On Mar 1, 1:55 am, "Rob Turk" wrote:
I'm looking for a sealant or kit to seal brass NPT inserts into a
polyethylene tank. This is a Kitfox header tank that has developed a leak at
one of the inserts. I'm probably going to use Mogas that has ethanol
additives. Any hints, tips, thoughts?

Thanks,
Rob

Hey Rob,

Before you mess up a perfectly good tank....

Just back that brass insert out. It's a pipe thread. Clean up the
mess as best you can.

I've have very good service using the thread sealant that Aircraft
Spruce sells called EZ Turn. I sealed every joint in the fuel system
that used that old white sealant. Some of them were leaking esp. at
the fiberglass wing tanks.

http://www.aircraftspruce.com/catalo...ezturnlube.php

Also try surfing the matronics Kitfox list.

Cheers,

Mark Napier

N246DR KFIII 582

wrote in message
oups.com...
Hey Rob,

Before you mess up a perfectly good tank....

Just back that brass insert out. It's a pipe thread. Clean up the
mess as best you can.

I've have very good service using the thread sealant that Aircraft
Spruce sells called EZ Turn. I sealed every joint in the fuel system
that used that old white sealant. Some of them were leaking esp. at
the fiberglass wing tanks.

http://www.aircraftspruce.com/catalo...ezturnlube.php

Also try surfing the matronics Kitfox list.

Cheers,

Mark Napier

Hi Mark, thanks for the tip. Certainly worth looking into..
Thanks!
Rob

I just looked at one of these jewels yesterday and I am impressed. Is anyone
using one? How do you like it. I'd really like to hear pro's and cons. I'm
presently using a King Skymap IIIC and could probably sell if for what a
Lowrance 2000C would cost.



Thanks



Paul Anton

N1431A

KPLU

I wrote a review of this unit back in 2005. Three parts.

http://www.aero-news.net/news/featur...83f4&Dynamic=1
http://www.aero-news.net/news/featur...0c0e&Dynamic=1
http://www.aero-news.net/news/featur...537A&Dynamic=1

I have not updated the review nor been informed of any changes to the
product.

Juan


"Tri-Pacer" wrote in message
. ..
I just looked at one of these jewels yesterday and I am impressed. Is
anyone using one? How do you like it. I'd really like to hear pro's and
cons. I'm presently using a King Skymap IIIC and could probably sell if for
what a Lowrance 2000C would cost.



Thanks



Paul Anton

N1431A

KPLU





--
Posted via a free Usenet account from http://www.teranews.com

Paul,

I've had the 2000c since it originaly was introduced. With the latest
upgrade all the pickey things that Juan alluded to have been fixed and
then some. If you read the manual, and UNDERSTAND what it's telling
you, you will find this unit has features that competitors costing $$$$
$$$ more don't have.

I'm in love with the big color screen, the optional screens are great
tooPlus you can configure the info shown on each page to suit
yourself.

Buy it, you won't be sorry...

Frank "WOOF" Beagle
Challenger Dealer CHII N797FB
http://www.geocities.com/frankbeagle
http://frankbeagle.blogspot.com
ph# 708-269-8057





Tri-Pacer wrote:
I just looked at one of these jewels yesterday and I am impressed. Is anyone
using one? How do you like it. I'd really like to hear pro's and cons. I'm
presently using a King Skymap IIIC and could probably sell if for what a
Lowrance 2000C would cost.



Thanks



Paul Anton

N1431A

KPLU