SCAT tubes

[paul330]

SCAT - my new worst best friend.......... 4 hours to get the 4 heating tubes on the engine

Why the bead of RTV down the tube? Do I really need it because it's not on at the moment......

 

[Jesse]

If a string breaks or gets cut, the bead if RTV will keep the string from unraveling, which will keep the scat tube itself from unraveling. You can probably get by without it, but it's easy to put on and is worth it.

 

[David Paule]

And of course, you don't need a continuous bead. A series of dots at each wrap is sufficient.........................................................

Dave

 

[paul330]

OK, makes sense. Next job.......

 

[N427EF]

4 Hours?

Paul, I feel for you, I never could figure out why we have to force a 2" ID.SCAT
Over a 2" OD Flange.
I like the orange SCAT hose and if only one of the aftermarket component
Sellers could "invent" a hose flange with a 1 7/8 " OD, no one would have to spend 4 hours installing a couple of hoses.
The unraveling problem would also be solved at the same time.

 

[Gary 40274]

cut wire shorter

There is no reason to have the wire so long that it has to slip over the flange. That just makes it impossible to get it over the flange. Trim the wire back inside the tube about 3/4 of an inch and bend the tip of the wire so it doesn't poke through the outside of the tube.

Then the tube slides on the flange easily. Secure with a clamp and you are done!

Gary Specketer

 

[David Paule]

And put a dab of the red RTV over the bent end, so it won't chafe the fabric.

Dave

 

[9GT]

You can stretch it out enough with both hands and two fingers each hand inside the tube working around the inside diameter. Just need the first half inch wide enough to get it started over the flange to easily slip over the tubing flanges with the wire wrapped over the flange too. I make sure that the clamp goes over the wire and string.

 

[paul330]

There is no reason to have the wire so long that it has to slip over the flange. That just makes it impossible to get it over the flange. Trim the wire back inside the tube about 3/4 of an inch and bend the tip of the wire so it doesn't poke through the outside of the tube.

Then the tube slides on the flange easily. Secure with a clamp and you are done!

Gary Specketer

Not sure I like that idea. It seems to me that there is a high probability of failure of the fabric around the edge of the flange. I'm just saying.........

 

[David Paule]

500 hours on the ones on my Cessna 180, no sign of wear.

Dave

 

[aerhed]

Depends on the angles and route, but many times scat will sag or collapse next to the flange if you don't have the wire all the way to the end over the flange. Some flanges are tighter than others, but if you arrange the wire right and prep the wire end just right it will usually fit. Helps to start on the tighest end. Then you can sorta screw the duct on once you get the wire edge over the flange. It will always last longer with the wire over the flange.

 

[jc11378]

Scat Tube and Internal Wire.

Well over the past 33 years I have been a A&P mechanic I have always trimmed back the internal wire back to just where it touches the flange bent the tip of the wire inside the duck to prevent it chafing a hole, and it has work perfect.

No Scat tube will not last for ever but most make it way past Engine TBO before they need replaced.

The biggest think i have found so many times is that people tie wrap scat tubing instead of clamps. I just found 3 wear spots on a friends RV on his engine mount worn thru the paint to bare metal where a loose tie wrap was holding scat tubing.

I have a rule no tie wraps to tie anything to any mounting location that's what clamps are made for and only tie wrap wire bundles together. i would rather see wire lacing or some kind to tubing conduit or wire protective wrap.

That's my opinion and let the primer ware begin hehe.

 

[aerhed]

Have at it then. I haven't been an A&P 33 years. Only 24 years with a few unlicensed years before that. Different people have different observations. Some just aren't correct. I used to terminate scat like you described, until I saw the deficiencies.