REFLECTOR:173 Exhaust pipes ....

Sun, 25 Jan 2004 10:44:10 -0500

Jim,

Ooooh, if I understand your predicament, maybe not. The "drawing" works best
on clear runs of pipe or, if there are connections or legs, the connections
are free to move with the pipe without messing up other alignments.
Sometimes, one pipe is drawn to the desired point, then you have to go to
the connecting pipe and draw it to get back to the its original
alignment...which may then cause the original pipe to go slightly out of
alignment, and so on and so forth.  It's about 10% science and 90% art.
Somebody that's good and has a "feel" for it, can do wonders...the rest of
us just use up a bunch of torch gas.  

Through the process, the intent is to area-heat with a larger torch head.
The pipe should be very hot but not cherry red.  Cherry red is for bending
(and creasing) the pipe.  With drawing, you are trying to "influence" the
pipe with contrasting heat/cold. 

If I understand your pipe configuration, it may be a long shot but desparate
people resort to desparate solutions.  If you've gone through 1 1/2 sets of
pipes so far, you may be close to the "D" word.

Chuck

-----Original Message-----
From: reflector-admin@tvbf.org [mailto:reflector-admin@tvbf.org]On
Behalf Of Jim Sower
Sent: Sunday, January 25, 2004 10:06 AM
To: reflector@tvbf.org
Subject: Re: REFLECTOR:173 Exhaust pipes ....

Chuck,
Thanks for the heads up.  It's in the shop to weld, but they won't get to it
until
early next week.  I'll go in tomorrow and talk to them about "drawing".  How
hot, over
how wide an area does it have to be?  There is a branch to a cylinder right
next to
(1/2" - 1")  where the bend has to be.  Will the process compromise the
welds in the
immediate area?  Can it be done if there are adjacent welds?  Besides the
runner from
the cylinder, about 1" - 1.5" from where the runner attaches, the pipe goes
into a
slightly larger pipe (snug fit) for a couple of inches and the joint is
welded.  Will
drawing work in that situation?
Maybe there's hope ... Jim S.

Chuck Jensen wrote:

> Jim,
>
> I was referencing drawing, not bending.  By heating on one side of the
pipe
> and quenching (cold wet towel) the other side, even heavy gauge piping can
> be "drawn" a surprising distance.  Heating and bending is not likely to
have
> a satisfactory outcome...unless your pipe is made of wrought iron.  If the
> shop says they can't do it or it won't work; that's one thing.  If the
> machine shop says they don't understand what you are asking about, "bolt"
> for the door, as they are "nuts."  This is not breakthru, leading edge
type
> stuff.  It may not work, but any machine shop that doesn't understand how
to
> try it is likely located under a shade tree.
>
> Chuck
>
> -----Original Message-----
> From: reflector-admin@tvbf.org [mailto:reflector-admin@tvbf.org]On
> Behalf Of Jim Sower
> Sent: Saturday, January 24, 2004 9:28 PM
> To: reflector@tvbf.org
> Subject: Re: REFLECTOR:173 Exhaust pipes ....
>
> The machine shop said they might be able to heat it enough over a wide
> enough area to
> bend it.  I got it back a couple of days later with a note that they
> couldn't bend
> it.  I could see it had been heated, and there was a wrinkle where they
> tried to bend
> it, but it wasn't bent and they couldn't do it.  If that sounds like thin
> info, you
> couldn't be more right.
> But I've already told you more than I know .... Jim S.
>
> Chuck Jensen wrote:
>
> > Jim,
> >
> > Did you ask if they would try the heating/quinching method of drawing
the
> > pipe into the alignment you needed.  It's kind of surprising how much
> > strategic heating and quinching can move even Sched 10 and 40 pipe
around.
> > If it doesn't screw up the metallurgy, it would maintain the integrity
of
> > the pipe by eliminating cuts/welds/creases.
> >
> > Chuck
> >
> > -----Original Message-----
> > From: reflector-admin@tvbf.org [mailto:reflector-admin@tvbf.org]On
> > Behalf Of Jim Sower
> > Sent: Saturday, January 24, 2004 5:18 PM
> > To: reflector@tvbf.org
> > Subject: REFLECTOR:173 Exhaust pipes ....
> >
> > All,
> > I've got a situation here that I don't know if it is about me or
> > the factory.  I have a 173 FG (with the 3" nipples in the cowl
> > for the exhaust to exit).  The plane came at me with exhaust
> > pipes (mild steel)  :-( that fit the cowl well.  About 18 months
> > ago the one on the starboard side cracked so I replaced it with
> > a SS unit.  The pipe didn't fit.  It pointed outboard about 1/2"
> > so it rested against the glass cowl.  I looked all over for a
> > place to bend it a little and finally got an exhaust shop that
> > would try (machine shops begged off saying they couldn't bend SS
> > pipes at all).  Well, they bent it so it would fit, but it
> > crinkled the pipe some where the bend was.  Recently I broke off
> > the last 6" of the other pipe (earlier post on Catto props) and
> > ordered another SS unit for the port side.  Took two months, but
> > it finally got here.  It was just a little tough to get the
> > flanges over the studs (but not near as bad as the previous one)
> > but OK.  When I went to put the cowl on, damned if it wasn't
> > splayed 1/2" INboard.  Once again, nobody can bend it, so I got
> > a machine shop welder (who I had used for some other stuff) to
> > make a cut (or two) to take a tiny wedge out of the pipe, bend
> > it back closed and stitch it up again.  HATE to do that, since
> > that's most likely where it will fail, but I had no alternative.
> >
> > My question to the list is:
> > Has anyone else had this problem (on replacement pipes)?  If it
> > is a common problem, one could surmise that the guy's jigs are a
> > little off.  If I'm the only one who has the problem, it would
> > seem that someone (the builder?) fastened the exhaust nipples
> > onto the cowl [in the wrong place / pointing the wrong
> > direction] and this is going to be an ongoing problem unless and
> > until I fix my cowl.
> >
>
> _______________________________________________
> 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
> _______________________________________________
> 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

--
Jim Sower ... Destiny's Plaything
Crossville, TN; Chapter 5
Long-EZ N83RT, Velocity N4095T

_______________________________________________
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