On Fri, 29 Aug 2003 00:07:15 GMT, Ernest Christley
wrote:

Corky Scott wrote:

Once again, I'm breaking from tradition regarding this building
method. What method do I use? Absolutely nothing.

Here's the way I figure it. I'm 55 now. I've welded this fuselage
together to the best of my ability and have closed off all openings.
Is it air tight? Proably not, there my be a pinhole somewhere. But
the fuselage will be sandblasted, at which time I get to inspect it
one more time, than it will be coated with primer and then coated with
paint. By the time all this is done, there will be precious few
places for water to get into, and that's without the fabric covering.


Corky,
It's not the water you see that hurts, it's the water in the air rhat
gets sucked in and out of those tubes as they heat and cool. As the
tubes cool they suck damp air in, and the moisture condenses out into
the tubes.
If you don't drain them at the low point the water builds up and it
WILL rust the tubes. Better to leave both ends wide open, and allow
the structure to breath, than to leave a few pinholes and not protect
the tubing.

With the fabric covering, almost no water will be able to reach the
tubes. And even if it could, there would be very very few places for
it to get inside the tube. Did I mention that the fuselage sits level
rather than tail down? Well that's a factor too.

Finally, even if I somehow left a gaping hole for moisture to enter
the tubing, which isn't the case but for argument's sake let's assume
so, it still won't matter much in my lifetime.

So I decided not to painstakingly drill a hole through every joint so
that linseed oil or whatever could be poured into it and then roll the
fuselage around to slosh each tube, then drain it out, sort of. I
mean sheesh, what a mess to deal with and how much added weight would
this be? All for no good reason that I could see. The entire
fuselage doesn't rust out from the inside, never has. Only a few
tubes that were improperly welded and were tail down ever rusted much
and then it took 30 or 40 years to do so.

Corky Scott


Corky, you're better off drilling a 1/8" hole in a low spot than to
leave just one small pinhole.

Used to drive a 18wheeler. Air brakes with big air tanks that had to be
bled, ie a short piece of rope is tied to a valve on the bottom of the
tank. If not bled regularly (every day), when you pull the rope all
sorts of dark brown gunk get blown out the bottom.

There was a spare tank sitting over in the yard that no one had used
for a year or two. I went over one day and pulled the rope on it.
Wasn't much pressure in it, but it squirted a slow steady stream of
water for a minute or so before petering out.

Here's the process. Airframe (which is acting as a tank here) get hot
during the day. The air pressure rises and forces humidity out of the
small amout of air in the tubes before the air gets squeezed out the
pinhole. Leaves maybe 0.1oz of water.

Night comes and the airframe cools. Very slowly, air, wet with evening
dew is drawn into the tube (with it's 0.1oz of water), where it waits to
start the cycle again the next day.

Paint won't help. If there's a pinhole, the paint will get blown off
when the pressure rises (the linseed oil runs into the hole from the
other side and acts as a plug, not a patch).

My unrequested advice: Either close it, and close it properly, or leave
it all the way open.