stuffing tube with or without teflon liner?

[SlickZERO]

I've run with and without teflon. I might add though, that the teflon I run in my setups is some pretty thick stuff from mtc, modelbaupirate, mhz, and also gundert. This stuff is pretty serious, and I think if people out there got a hold of it (those that don't run teflon), they would be pretty amazed at how much tougher it feels than whats offered on ose, kintec, etc.

Not all teflon is the same.

http://keithbradleyboats.com/product/teflon-liners-for-316-flex-tubes/

Just looked it up, found you can get the heavier weight teflon in the U.S., 3/16". I STRONGLY suggest anyone building a new boat buys the matching stuffing tube for their 3/16" boats.

Anyway to the OP, you got a pretty powerful and capable setup you're building, clearly there is no "wrong," way but if you can, I would pick up thicker teflon I think once you do a side by side comparison you'll be surprised.

The site for the teflon tube shows in lengths of 4". Wouldn't you need enough to go all the way up the tube?

[iridebikes247]

Yeah it should go up the entire tube, but you can ask Keith for a longer length I'm sure.

[dmitry100]

Guys, what are some good brands of .187 teflon? I use the octura stuff from ose and was wondering if theres any better stuff out there... that can be used with 9/32 tube.

But anyway, you guys are saying to sand the flex... is it possible to flatten the flex's like the ones from OSE with bigger wire strands? With the amount of sanding that would probably take-- It won't weaken the flex too much?

[nichismo]

Always many good points here on OSE and it helps us sport boaters learn and improve our boats, so thank you for that.

On a side note, this statement is awesome and maybe you can pm me a picture when you have a chance!
"as I type this, I'm looking up at a shelf with NINE 100mph+ boats"

I'm not trying to subliminally say anything other than that is pretty damn cool.
As I type this, I'm looking at a messy desk that needs to be cleaned! LOL

exactly what I was thinking..... UNTIL:

You will find in this hobby that there are a whole lot of people that just do what is popular in certain groups, and consider a lot of how they do things as gospel simply because so many other people are doing it. There are others that don't do things "just because", and insist on finding out the truth for themselves. The second group is the group that breaks away from mediocrity, while the first is "the majority".

I read this ^^^

which I found so utterly damning and intuitively foreboding for my own perspective, that I went to change my signature to consist of it and it only.....






only to discover it was too large to fit xD

so many times ill be building or working on my current project, and ill be indecisive in making my next purchase or how to proceed with my current fiasco thats delaying progress... and part of me wants to go a certain route, that route giving me satisfaction to my curiosity and exciting me as well, but at the same time I have this other voice, an obligation to go the other route against my natural experimentation, just because I know the traditionalist "majority group" makes me feel like I should.

But now ill know what to do next time :D

lol but to be on topic, ive only spent my short time in this hobby with scale hydroplanes, and none, absolutely none, run teflon liner. We all use .25" shafts and it seems to me that the bigger the shaft, the less likely teflon is to be used

[SweetAccord]

I will try to add my 2 cents here without ruffling feathers.

I have run with and without Teflon in numerous boats including most of my SAW boats. When I consider running Teflon it has a lot to do with the type of cable I will be running and in what installation. Hopefully we can all agree a short shaft mono or cat will have different characteristics than a sport hydro or rigger with a long cable. Other factors come into play such as collet vs. square drive, cable vs. wire, .150 vs .187 vs. .25 size cable. There is no right or wrong answer and if properly done either method can be reliable.

From my own preferences I run Teflon on almost all .150 cable applications whether it is SAW or an oval boat. Partly because I can use 1/4" tube with a liner or if I need to step up to .187" I can remove the liner and run without. Also because the .150 cable I run is very soft and the Teflon seems to dampen it a little better. On .187" and .25" cable I usually do not run Teflon liners. All my heat racing boats whether gas, nitro or FE run without liners. The one exception is one variant of my SAW Q hydro where I do have a Teflon liner. I have three Q saw hydro's, one with .187 cable and a liner, one with .187 cable and no liner and one with a wire drive. I did not see any measurable difference between with or without Teflon on that boat and I was turning plenty of RPM. There was a significant difference going to a wire drive but that is another story.

Teflon does need to be carefully checked and I prefer to only use oil with Teflon and never grease. Grease tends to make the Teflon liner spin even when scuffed and CA'ed in place. When using just a brass stuffing tube the choice between oil and grease is dependent on the application and length of race. My preference is typically grease for heat racing boats and oil for SAW boats.

Some general hints regardless of whether the stuffing tube has Teflon or not. Sanding the cable. I will chuck up the cable in a hand drill and using a 1" belt sander with a fine grit belt and sand the cable down to remove the high points formed by the twisted wires. I will tend take some 600 grit sand paper and some oil and spin the shaft again using the drill till the cable is almost polished. I avoid sanding the ends where the collet or square drive are and the output side whether soldered into a ferrule or onto a stub shaft. I just sand the middle section down. The diameter change is around .015". There is the argument that having the stock rounded wires in the cable has less contact area with the stuffing tube as it should only be a line contact. However in all my testing the sanded cable is always smoother and results in higher speeds.

I prefer single bends over S-bends with the argument that S bends tend to have more change in direction. Sometimes they are unavoidable so just try to increase the bend radius as large as possible.

Cables and collets must be aligned. The same goes for the strut and cable. Having jogs and abrupt angle changes are never helpful for reducing friction.

Run the correct size stuffing tube. Too small and the cable will see lots of friction from the inner wall, too large and the cable will tend to whip. The table below is copied from the OSE shop and I agree with the recommendations for the majority of applications:

Suggested stuffing tube sizes when used "WITH" Teflon tubing:
3/16" brass for Octura .098 Teflon tubing.
7/32" brass for Octura .130 Teflon tubing.
1/4" brass for Octura .150 Teflon tubing.
9/32 brass for Octura .187 Teflon tubing.
11/32 brass for Octura .250 Teflon tubing.

Suggested stuffing tube sizes when used "WITH NO" Teflon tubing:
5/32" brass for .098 Flex Cable.
3/16" brass for .130 Flex Cable.
7/32" brass for .150 Flex Cable.
1/4" brass for .187 Flex Cable.
5/16" brass for .250 Flex Cable

Here are some of my notable set-ups:
T-Hydro SAW: 3/16" flex cable with squared end on motor side and conventional 3/16" stub shaft and ferrule. Brass stuffing tube only.
S-Hydro SAW: 3/16" flex cable with welded stub shaft and collet on the motor side. Brass stuffing tube only.
Q-Hydro SAW: 2mm wire drive with thick Teflon liner and bonded 3/16" stub shaft. Brass stuffing tube with thick cross section Teflon. i.e. the wire had little clearance to the inner wall.
N2 and P mono SAW: 2mm wire drive with short brass stuffing tube and Teflon liner plus 3/16" stub shaft. Flooded well design.
N2 heat race mono: .150 cable with Teflon liner and bonded stub shaft.
P heat race mono: .187 cable directly in brass and welded stub shaft.
Q mono heat race: 3mm wire drive with flooded well. 1/4" Brass stuffing tube goes into strut. Short Teflon piece with tight diameter seals flooded well near the motor side.
P-Ltd Rigger: .150 cable with Teflon liner and bonded stub.
P-Ltd and P sport hydro: .150 cable with Teflon liner and bonded stub.
Q/T heat race rigger: .187 cable with squared motor end running directly in brass tubing.
T Offshore and Open cat: 1/4" cable with welded end running directly in brass tubing.
S/T mono SAW; 1/4" coarse wire cable with squared motor end running directly in brass tubing.

All my nitro and gas boats run without Teflon whether for heat racing or SAW.

There is no silver bullet to answer the debate. It's preference and set-up to make it work.

TG

Can you elaborate on your statement of "there was a significant difference going to a wire drive but that is another story."

[SD Eracer]

I've run both, and noticed no real difference between the two except more grease fling with teflon lined stuffing tubes. I use a strip of painters tape arced over the collet to catch any fling and keep the inside of my boats clean during runs.

Also, I prefer to use teflon liners on boats with shorter stuffing tubes, like on my Pursuit. Great at preventing water from moving up into the hull.

However, my Genesis with has a much longer stuffing tube, and no water enters the hull even without the liner.

In short, for me, if the boat originally ran a .150 flexshaft and I stitch to a .187, I remove the liner. If the boat was originally setup with a .187 flexshaft and sized for a liner, I continue to use the liner.

[dmitry100]

The Octura .187 teflon seems to be a tad bit soft... after I sanded my OSE .187 flex it seems to have scuffed up the entire teflon tube inside.
Maybe I sanded the flex down a bit too much? or should I be using some better teflon that isn't as soft...

[Tamelesstgr]

I ran my first stuffing tube and .187 cable with no teflon liner yesterday. I used my traditional marine grease at the end of the stuffing tube where the prop sits. For the inner portion of the stuffing tube, I tried to get some 75w gear oil in the tube after the cable was inserted and connected to the motor. Is there a particular way to insure you get adequate lube in the stuffing tube when running without a liner???

[SD Eracer]

Yes, if your strut or stinger has a 3/16 solid bushing, just use a syringe or Proboats marine grease gun. You don't need a lot of lube to prevent water from going up the tube. Make sure you have the right sized flexshaft for that tube without a liner, and make sure to lube the strut or stinger well along with the flexshaft itself.

Shoot or inject a good amount of the marine grease into the strut or stinger end. I typically give 4-5 squirts with the grease gun, or about tip of the finger amount of grease though a plastic syringe.

Then before you insert the flexshaft, make sure to fully cover it some grease as well, especially the tip. If you stick a dry flexshaft into the tube, it will bring all the lube up with it and you will waste it.

As you push the flexshaft into the tube, constantly twist/rotate it while also moving it up and down to help move the grease throughout the tube before you finally push it into the collet.

I make sure to clean any grease off the end of the collet before inserting it.

Here is a good video on how you move the flexshaft up and down as you insert it into the stuffing tube: https://www.youtube.com/watch?v=1ZjOXuHdmYU

Please note that the boat model in the video has a removable brass bushing which makes lubing easy because you have a much larger opening to easily insert an already greased flexshaft. If you have a solid Teflon bushing, its much narrower and a lot harder to get a greased flexshaft through it, best to inject the grease with syringe or grease gun.