Rust prevention: Inside fuselage

[Michael Horowitz]

Elsewhere I"m listening to a discussion about using boiled linseed
oil/Tubeseal to protect against rust on the inside of the fuselage.
There appear to be two views: one is start pouring the oil in thru a
small hole until full, then seal the hole. The second view is fill her
up, slosh around to coat, drain and leave the hole open.

Is there an authoratative source for which approach to take?

In either case (unless the fuselage was specifically built to be a
seaplane), tubing isn't interconnected (correct me if I'm wrong), so
if you you drill a hole in the lower left longeron and pour in oil,
all that will be treated is the lower left longeon - not the tailpost,
not cross tubing. Correct?

- Mike

[Stealth Pilot[_2_]]

On Sat, 18 Aug 2007 06:32:14 -0400, Michael Horowitz
> wrote:

>Elsewhere I"m listening to a discussion about using boiled linseed
>oil/Tubeseal to protect against rust on the inside of the fuselage.
>There appear to be two views: one is start pouring the oil in thru a
>small hole until full, then seal the hole. The second view is fill her
>up, slosh around to coat, drain and leave the hole open.
>
>Is there an authoratative source for which approach to take?
>
>In either case (unless the fuselage was specifically built to be a
>seaplane), tubing isn't interconnected (correct me if I'm wrong), so
>if you you drill a hole in the lower left longeron and pour in oil,
>all that will be treated is the lower left longeon - not the tailpost,
>not cross tubing. Correct?
>
>- Mike

no. it is recommended aircraft practise for a hole to be drilled
between the tubes in the centre of the area the joining tube will sit
over. that's if they followed standard practise. so you can pour in
one end and rotate the fuselage all about and the fluid will
eventually migrate through the entire fuselage.

the two fluids work differently. linseed is heated before use to thin
it out and so that you can feel how far it has reached. it needs to be
sealed off since the setting to a varnish absorbs oxygen and leaves
the interior air in the tube oxygen depleted. once it sets off it
stays in place.

tubeseal has components in it that wick out over the surface of the
metal. I tubesealed my fuselage six months ago and it still seems to
be fluid.

another method I've found to still be working after 50 years is to
swab the tubes out with lanoline (wool grease) the auster fuselages
have this and in my cutting out of a corroded part on the rudder I
discovered that the corrosion had not spread from the area that was
damaged.

I went with tubeseal when I redid the fuselage.

Stealth Pilot

[Michael Horowitz]

On Sat, 18 Aug 2007 23:11:10 +0800, Stealth Pilot
> wrote:

>On Sat, 18 Aug 2007 06:32:14 -0400, Michael Horowitz
> wrote:
>
>>Elsewhere I"m listening to a discussion about using boiled linseed
>>oil/Tubeseal to protect against rust on the inside of the fuselage.
>>There appear to be two views: one is start pouring the oil in thru a
>>small hole until full, then seal the hole. The second view is fill her
>>up, slosh around to coat, drain and leave the hole open.
>>
>>Is there an authoratative source for which approach to take?
>>
>>In either case (unless the fuselage was specifically built to be a
>>seaplane), tubing isn't interconnected (correct me if I'm wrong), so
>>if you you drill a hole in the lower left longeron and pour in oil,
>>all that will be treated is the lower left longeon - not the tailpost,
>>not cross tubing. Correct?
>>
>>- Mike
>
>no. it is recommended aircraft practise for a hole to be drilled
>between the tubes in the centre of the area the joining tube will sit
>over. that's if they followed standard practise. so you can pour in
>one end and rotate the fuselage all about and the fluid will
>eventually migrate through the entire fuselage.
>
>the two fluids work differently. linseed is heated before use to thin
>it out and so that you can feel how far it has reached. it needs to be
>sealed off since the setting to a varnish absorbs oxygen and leaves
>the interior air in the tube oxygen depleted. once it sets off it
>stays in place.
>
>tubeseal has components in it that wick out over the surface of the
>metal. I tubesealed my fuselage six months ago and it still seems to
>be fluid.
>
>another method I've found to still be working after 50 years is to
>swab the tubes out with lanoline (wool grease) the auster fuselages
>have this and in my cutting out of a corroded part on the rudder I
>discovered that the corrosion had not spread from the area that was
>damaged.
>
>I went with tubeseal when I redid the fuselage.
>
>Stealth Pilot

This bit about sealing the tube after sloshing/draining has some
logic, but doesn't it seem to be a conflict when we leave a drain hole
at the base of the four struts, at the bottom of the landing gear, in
fuselage tubing, the horizontal stabilizers and elevators, and the
rudder? - MikeH

[Stealth Pilot[_2_]]

On Sun, 19 Aug 2007 06:02:11 -0400, Michael Horowitz
> wrote:


>>I went with tubeseal when I redid the fuselage.
>>
>>Stealth Pilot
>
>This bit about sealing the tube after sloshing/draining has some
>logic, but doesn't it seem to be a conflict when we leave a drain hole
>at the base of the four struts, at the bottom of the landing gear, in
>fuselage tubing, the horizontal stabilizers and elevators, and the
>rudder? - MikeH

you have me there. I'm not sure whether you mean drain holes in the
fabric cover or drain holes in the structural tubing.
what aircraft type is this?

in any case using tubeseal wont hurt and is cheap.
Stealth Pilot

[Peter Dohm]

> >>Elsewhere I"m listening to a discussion about using boiled linseed
> >>oil/Tubeseal to protect against rust on the inside of the fuselage.
> >>There appear to be two views: one is start pouring the oil in thru a
> >>small hole until full, then seal the hole. The second view is fill her
> >>up, slosh around to coat, drain and leave the hole open.
> >>
> >>Is there an authoratative source for which approach to take?
> >>
> >>-----portions snipped-----
> >
> >no. it is recommended aircraft practise for a hole to be drilled
> >between the tubes in the centre of the area the joining tube will sit
> >over. that's if they followed standard practise. so you can pour in
> >one end and rotate the fuselage all about and the fluid will
> >eventually migrate through the entire fuselage.
> >
> >the two fluids work differently. linseed is heated before use to thin
> >it out and so that you can feel how far it has reached. it needs to be
> >sealed off since the setting to a varnish absorbs oxygen and leaves
> >the interior air in the tube oxygen depleted. once it sets off it
> >stays in place.
> >
> >tubeseal has components in it that wick out over the surface of the
> >metal. I tubesealed my fuselage six months ago and it still seems to
> >be fluid.
> >
> >another method I've found to still be working after 50 years is to
> >swab the tubes out with lanoline (wool grease) the auster fuselages
> >have this and in my cutting out of a corroded part on the rudder I
> >discovered that the corrosion had not spread from the area that was
> >damaged.
> >
> >I went with tubeseal when I redid the fuselage.
> >
> >Stealth Pilot
>
> This bit about sealing the tube after sloshing/draining has some
> logic, but doesn't it seem to be a conflict when we leave a drain hole
> at the base of the four struts, at the bottom of the landing gear, in
> fuselage tubing, the horizontal stabilizers and elevators, and the
> rudder? - MikeH

There are no holes are left to the outside of the metal frame, when the work
is complete. In addition, all of the tubes should have become completely
coated on the inside and all will have been drained--none are left full.
IIRC, the outside is treated for rust prevention after the inside has been
drained and sealed. Remember that the location of fill and drain holes does
have some structural implications, and that some locations may be difficult
to keep clear for the subseqent filling and draining.

As to exactly what to use and how to use it, I would recommend joining an
EAA chapter and attending their meetings and functions. There are a lot of
mechanics and restorers, in addition to builders, who are members and who
are quite knowledgeable and experienced in this sort of work--however,
relatively few of them read usenet and fewer post.

That availability of knowledge and experience is one of the strengths of the
EAA Chapter organization--otherwise you would need to apprentice as a
mechanic to gain that type of knowledge.

Peter

[Michael Horowitz]

On Sun, 19 Aug 2007 20:52:22 +0800, Stealth Pilot
> wrote:

>On Sun, 19 Aug 2007 06:02:11 -0400, Michael Horowitz
> wrote:
>
>
>>>I went with tubeseal when I redid the fuselage.
>>>
>>>Stealth Pilot
>>
>>This bit about sealing the tube after sloshing/draining has some
>>logic, but doesn't it seem to be a conflict when we leave a drain hole
>>at the base of the four struts, at the bottom of the landing gear, in
>>fuselage tubing, the horizontal stabilizers and elevators, and the
>>rudder? - MikeH
>
>you have me there. I'm not sure whether you mean drain holes in the
>fabric cover or drain holes in the structural tubing.
>what aircraft type is this?
>
>in any case using tubeseal wont hurt and is cheap.
>Stealth Pilot


It's a rag and tube a/c and we're talking holes in the steel.
I can send you an illustration via e-mail showing the hole in the
landing gear strut if you're interested - Mike

[Morgans[_2_]]

"Michael Horowitz" > wrote

> It's a rag and tube a/c and we're talking holes in the steel.
> I can send you an illustration via e-mail showing the hole in the
> landing gear strut if you're interested - Mike

That goes against convention, for rag and tube aircraft, from everything I
have read.

The tubes should have holes at joints, so all of the insides of the tubes
are connected to each other. All of the tubes should not be open to the
outside air. That is the only way that rust inside of the tubes can be
prevented.

Linseed oil is (one of the most popular things) used, because of the ability
to coat the inside of the bare metal tubes, and because the oil oxidizes
(binds with the free oxygen) and that leaves an environment inside the tubes
that prevents the steel from rusting. If you are capable of keeping the
inside without free oxygen, there can be no oxidation (rusting) of the
tubes.

Some aerobatic rag and tub aircraft have a air fill valve, and a pressure
gauge where it can be checked at every pre-flight. It is then filled with
some gas, like nitrogen or argon. If the pressure is lower, or at
atmospheric pressure, there is a crack somewhere, meaning that it might not
be structurally sound, especially for high G loads.

I think you have some decisions to make, as how to proceed with your
airplane. It would seem to me that you need to be able to see if the tubes
are still sound, and that you need to seal that sucker up and coat the
inside with something.

JMHO.
--
Jim in NC

[Ernest Christley]

Morgans wrote:
> "Michael Horowitz" > wrote
>
>> It's a rag and tube a/c and we're talking holes in the steel.
>> I can send you an illustration via e-mail showing the hole in the
>> landing gear strut if you're interested - Mike
>
> That goes against convention, for rag and tube aircraft, from everything I
> have read.
>
> The tubes should have holes at joints, so all of the insides of the tubes
> are connected to each other. All of the tubes should not be open to the
> outside air. That is the only way that rust inside of the tubes can be
> prevented.
>

There seems to be two conventions then, Jim. One is as you describe.
The other is to make sure that water doesn't have a place to collect by
providing a drain hole at the lowest point. The Dyke Delta's rear spar
and elevon spars are completely open.

If kept in a reasonably dry environment, the less labor intensive method
is sufficient. The Delta prototype, N555A, has lasted 45 years. John
Dyke just announced that he has found rust in the elevon spars and may
have to ground the plane.

If you expect the airplane to fly over the beaches of the world forever,
then a 100% guaranteed seal is necessary. For the rest of us, I'm not
so sure that is the case.

[Morgans[_2_]]

"Ernest Christley" <> wrote

> There seems to be two conventions then, Jim. One is as you describe. The
> other is to make sure that water doesn't have a place to collect by
> providing a drain hole at the lowest point. The Dyke Delta's rear spar
> and elevon spars are completely open.
>
> If kept in a reasonably dry environment, the less labor intensive method
> is sufficient. The Delta prototype, N555A, has lasted 45 years. John
> Dyke just announced that he has found rust in the elevon spars and may
> have to ground the plane.
>
> If you expect the airplane to fly over the beaches of the world forever,
> then a 100% guaranteed seal is necessary. For the rest of us, I'm not so
> sure that is the case.

Humm.

I wonder if the extra labor to do the sealed method is that significant,
compared to all of the time and effort it takes to weld up a good fuselage.
I tend to think the extra effort is not significant, but to each his own.

There is something in me that _does not want to accept_ the fact that
there can be damage happening that can not be inspected visually, and that
gives no sign that "bad things" are happening, and if allowed to continue,
could cause a failure and an almost certain injury and possible death. I
can not accept that a little more effort in sealing the inside of the tubes
is not worth what ever extra effort it takes. That is just me, though.

I guess you know where I stand on the subject now, don't you! <g>
--
Jim in NC

[Stealth Pilot[_2_]]

On Sun, 19 Aug 2007 11:54:16 -0400, Michael Horowitz
> wrote:

>On Sun, 19 Aug 2007 20:52:22 +0800, Stealth Pilot
> wrote:
>
>>On Sun, 19 Aug 2007 06:02:11 -0400, Michael Horowitz
> wrote:
>>
>>
>>>>I went with tubeseal when I redid the fuselage.
>>>>
>>>>Stealth Pilot
>>>
>>>This bit about sealing the tube after sloshing/draining has some
>>>logic, but doesn't it seem to be a conflict when we leave a drain hole
>>>at the base of the four struts, at the bottom of the landing gear, in
>>>fuselage tubing, the horizontal stabilizers and elevators, and the
>>>rudder? - MikeH
>>
>>you have me there. I'm not sure whether you mean drain holes in the
>>fabric cover or drain holes in the structural tubing.
>>what aircraft type is this?
>>
>>in any case using tubeseal wont hurt and is cheap.
>>Stealth Pilot
>
>
>It's a rag and tube a/c and we're talking holes in the steel.
>I can send you an illustration via e-mail showing the hole in the
>landing gear strut if you're interested - Mike

tailwind at westnet dot com dot au and I kill spammers and rabbits for
stress relief :-)

I'm wondering whether they intended to fill the holes with blind
rivets?

Stealth Pilot

[Blueskies]

"Morgans" > wrote in message ...
>
> Some aerobatic rag and tub aircraft have a air fill valve, and a pressure gauge where it can be checked at every
> pre-flight. It is then filled with some gas, like nitrogen or argon. If the pressure is lower, or at atmospheric
> pressure, there is a crack somewhere, meaning that it might not be structurally sound, especially for high G loads.
>
>

Some helicopters also pressurize the rotor blades and monitor real time for pressure drop...