Who makes the best flex cable?

[3-UP]

Aeromarine has none available either. Guess I need to learn to make my own. Anyone point me in the right direction on how to do it correctly? I don't trust loctite. I want to solder, braze or weld mine.

Aeromarine has the 3/16 - 3/16 cable you just have to purchase the next longer length.

[kfxguy]

The only problem I see with ALuminum is the torch needed to braze the cable might melt the jig but, now you know that, maybe you can work around it.

I'm getting a piece of bulk H&M .125" (3.2mm) to see if I can make it fail.

so....will silver solder not be strong enough? i can tig weld them but that may be a challenge. heres the process i'm thinking in my head....

process 1....

solder tip of cable about 1/2". chuck in my lathe. turn down a little bit. drill stub shaft in the lathe 1/2" deep for cable to fit. tin the stub shaft with silver solder. put in jig, solder together.

process 2.

procure a square drive stub. drill to fit flex. same process as above but then grind or cut down the larger part of the stub shaft. maybe i'm way off. guess i wont know till i try and test.

[Peter A]

Trav you're on the right track. make sure you mill out enough to give the room needed. If the worry is melting the ali, make a steel jig, it just takes a little longer to machine. I use brass tubes to sleeve the cable and shaft, with electrical solder and this has been fine for the setups I use. I've even got away with .150 flex between a TP 4050 2200kv 4S 2P and 548,447 props without failure! You may like to do some testing on joints with scrap bits to determine the best type of join between flex and stub, see how much force it takes to fail a join.

[ray schrauwen]

Is silver solder strong enough?? No idea but, Ed Hughey uses whatever requires the heat of a Jeweler's torch. More silver= stronger. I'm guessing but, I think they are braised....??? I know the .150- 3/16" Hughey cables are braised as you can see the goldish color of the welding material.

[kfxguy]

Trav you're on the right track. make sure you mill out enough to give the room needed. If the worry is melting the ali, make a steel jig, it just takes a little longer to machine. I use brass tubes to sleeve the cable and shaft, with electrical solder and this has been fine for the setups I use. I've even got away with .150 flex between a TP 4050 2200kv 4S 2P and 548,447 props without failure! You may like to do some testing on joints with scrap bits to determine the best type of join between flex and stub, see how much force it takes to fail a join.

well i have the perfect test bed for seeing if they fail. problem is ill have to come up with a way to not lose my prop should the shaft fail. ugh

although.....i'm pretty sure my drill on the low speed setting has enough tq to break a shaft. I might make a fixture for that to test.

[Doug Smock]

Is silver solder strong enough?? No idea but, Ed Hughey uses whatever requires the heat of a Jeweler's torch. More silver= stronger. I'm guessing but, I think they are braised....??? I know the .150- 3/16" Hughey cables are braised as you can see the goldish color of the welding material.

You're right Ray.
Ed is using 45- 56% silver. It is much stronger than say Stay Brite 80 silver solder.

[olwarbirds]

You're right Ray.
Ed is using 45- 56% silver. It is much stronger than say Stay Brite 80 silver solder.

So what I thought was a weld type adhering, was the heat from using a hotter soldering torch for this type of higher silver content/grade solder discoloring the shaft. It never ceases to amaze me the knowledge thats available here on this forum ! tks Doug... DJ

[Fella1340]

I would be looking at braising with high silver content rod or tig welding Travis. The soft solders and the type of abuse you throw at things may not be a good match:) any thought given to using loctite?They areholding a lot of high power saw cat flexes together.
The flexes I got from kintec were braised and they running almost true coming outcome the shaft. You couldn't get them much closer. If you got a good fit for your flex to slide into the shaft I don't think a complicated jig is needed. Mill a ""V" into a piece of flat aluminum bar that you've taken a skim off each side and then mill a 3/16" bullnose into some smaller bar and cut into pieces for clamps on top...You get the idea...
Lots of ways to do it

[jcald2000]

Ed told me to use 45% silver solder about a decade ago. I found that the local Welding retailers have Harris 45% brazing kits on the shelf which is enough for about 12 shafts. It is a hard wire, not rod with flux.
He was using an electric furnace at that time to get even heating.

[olwarbirds]

I have used the loctite 638 for doing a .150 flex and shaft. I run them on a couple of 4S setups with no probs. I have been curious if it would work on .187 in my 6S setups. I would doubt that it would hold up in my 8-10s .250 setups. I would hate to try it and like Travis mentioned and loose one of my good props. I have heard like previously mentioned that alot of saw guys do it this way. I would like to hear exactly what their process is to keep it all together... DJ

[T.S.Davis]

We tried to weasel Ed's process out of him around a camp fire one night in 2005. He wasn't giving it up.

[kfxguy]

We tried to weasel Ed's process out of him around a camp fire one night in 2005. He wasn't giving it up.

I wish he would at this point, so someone could carry on with it.

[rickwess]

We tried to weasel Ed's process out of him around a camp fire one night in 2005. He wasn't giving it up.

Offer him royalties on every cable you make for sale.

[gsbuickman]

Heya Travis ,

The only flex's I've had trouble with is AQ shafts. I switched to Pro-Boat 3/16" and I haven't had a lick of problems since on 5-6s. have you tried pro boats shafts ?. Compared to AQ their R&D is tits ...

[78MaicoRider]

Let me know. I'm gonna have to figure out how to make them and make them perfect straight. Anything less is not acceptable to me.

Chuck the cable in a lathe and the stub shaft in the tail stock to braze them. If set up properly they will be perfect every time.

[kfxguy]

Heya Travis ,

The only flex's I've had trouble with is AQ shafts. I switched to Pro-Boat 3/16" and I haven't had a lick of problems since on 5-6s. have you tried pro boats shafts ?. Compared to AQ their R&D is tits ...

Nah i havent tried them. i think my hobby shop stocks them but i'm not sure if they carry 3/16. i'll check and have a look at them. thx!

[kfxguy]

Chuck the cable in a lathe and the stub shaft in the tail stock to braze them. If set up properly they will be perfect every time.

not a bad idea!

[T.S.Davis]

I wish he would at this point, so someone could carry on with it.

At this point someone is going to have to take up the torch........hey, I made a pun...LOL There are options of course but none of them measure up to Ed's. Hope I'm not hurting anyone's feelings.

There were a lot of his family racing for a while. You would think one of them would have wanted to learn from the master and use the skill for evil........er........I mean profit.

I also tried to talk one of our club guys into doing it as his dad has mad machinist skills and could build a ridiculously accurate jig just for this purpose.

"He was using an electric furnace at that time to get even heating." Jim, you didn't happen to see said oven did you? I should have taken a minute and raided his trailer at the 05 nats. He was old even then. I could take em.

[kfxguy]

At this point someone is going to have to take up the torch........hey, I made a pun...LOL There are options of course but none of them measure up to Ed's. Hope I'm not hurting anyone's feelings.

There were a lot of his family racing for a while. You would think one of them would have wanted to learn from the master and use the skill for evil........er........I mean profit.

I also tried to talk one of our club guys into doing it as his dad has mad machinist skills and could build a ridiculously accurate jig just for this purpose.

"He was using an electric furnace at that time to get even heating." Jim, you didn't happen to see said oven did you? I should have taken a minute and raided his trailer at the 05 nats. He was old even then. I could take em.

lmao! I wonder if anyone here knows him personally. maybe this thread will be seen and he might be willing to pass his method on. I hope...... and prayers for him for his health issues.

[78MaicoRider]

not a bad idea!

Using the lathe how I make long drill bits when needed.

[jcald2000]

Terry, no I did not, he said he built it. If you looked at his boats in 05 you could imagine what his electric oven looked like. Star Wars!

[T.S.Davis]

Yeah, Ed is truly a gifted builder. His fleet inspired a bunch of us to tackle building things we never would have tried before.

I've been doing a little research. Pretty sure Ed is induction soldering. I haven't figured out how to build one yet.

[olwarbirds]

Yeah, Ed is truly a gifted builder. His fleet inspired a bunch of us to tackle building things we never would have tried before.

I've been doing a little research. Pretty sure Ed is induction soldering. I haven't figured out how to build one yet.

Terry, after reading this I started doing some research. There are some interesting vids etc on how to do this and several on different ovens. I can definately see using inductions soldering for alot more apps than just flexshafts...tks.. DJ

[Fella1340]

Some good hard silver solder or silver braising rod would work fine. The difference between with the silver braising rod is that the flux is already on it. (there are some lower temperature braising rods out there.The hard silver wire is nice as you can clean with flux before starting the weld. I have used a ton of the hard silver wire building induction furnaces for heat treating leaf springs and induction furnaces for melting metals, silver and gold. It's tough stuff.
Joining stainless steels requires perfect cleanliness and a lot of heat, oxygen/acetylene or possibly oxygen/propane. Both parts are orange to red hot when solder is applied. It will take some practise to get it dialed in. I believe the braising may be more forgiving overall with temperature and cleaning required. I know once you have a bad join started it can be very difficult to recover without starting over. I used to have to join copper and brass to stainless, that was very difficult. Figuring out the optimum temperature for doing the weld is the big part of getting a consistent job.
If you haven't looked at the kintec flex shafts you should, they run true and all well made. I will personally go with tig welding first if I need to make a few cables up., less heat put in either part while welding. The hard silver rod isn't very forgiving and unless you plan on setting up shop to do them it may frustrate more than anything else. I'm not to familiar with high silver braising rod but I would imagine there are some easier blends out there that will be just as strong.
I'd anybody is worried about heat treatment of the shafts bring lost, they just aren't very hard to begin with. I haven't seen any made other than 300 series stainless for the stub shafts. Most properly heat treatable stainless start in the 400 series, similar to what you see better quality knives made of. Not to say they can't be done but they won't be much tougher than the knife, fork and spoon we use around the dinner table. A lot of this is drawing from a mushy memory from many years ago so I hope I got it right. I didn't realize we had reached crisis levels for rc boat cables!
The jig I see being a simple enough affair. Using an aluminum tube with windows cut out for braising may cause issues drawing the heat away, it's tough enough to get your parts up to Temperature, the window is small for doing the job correctly. You would want to have a pile of practise pieces ready to try out first. The stub shafts could get cherry red pretty quick which could cause Warping. There's an art to doing it. That's about all I recall, hope the info is accurate!

[ray schrauwen]

I found this and learned a few things from it. I might make up a little crucible like this...

[gsbuickman]

You can also use an empty rifle cartridge (brass) to solder the first few Inches of your flex. Get a shell like 7.62x39 or 7.62x54r and clean it out & flush with brake cleaner so there's no residue. heat the shell up with a butane torch and fill it with solder until it's about 1/2 way full, then start dipping your flex shafts in the molten solder.

As you dip the solder will penetrate the shaft but the level of the solder will also rise so be careful not to overflow it or you'll have a mess to clean up. the shell retains a lot of heat so once you get it good & molten, It stays that way for a while, just like it does if you used the same torch to solder bullet connectors too ��

[Fella1340]

The crucibles work work very well. The pipe cap thing will work pretty well but a graphite crucible for around 10 bucks on eBay keeps the solder nice and clean and heats up within seconds. It's great for tinning wire as well and your not getting any cross contamination from the steel cap. I've had my graphite crucible 10 plus years and it's still like new. Good for melting silver and gold to!

[TheShaughnessy]

One question we get asked occasionally is the technique for soldering a flex ferrule to a flex cable. Let's go through the items you will need. A-The proper solder, namely a low temperature silver solder (as used in sweat soldering copper plumbing pipes). B-The proper flux which is borax based, definitely NOT an acid flux ( which can wick into the cable and cause rust or corrosion. C-Matching flex cable and flex ferrule. D-A propane torch (A soldering iron does not develop enough heat for silver solder). E-A wire brush to remove oxide down to bare metal (this applies to .250 diameter cable) F-A vice to hold the cable and ferrule while soldering. ***Let's go though the procedure step by step. First - clean the cable end you will be soldering, brushing with the wire brush the length of the wire, not across the cable. After you have cleaned the end of the cable, clamp it in your mounted vice with approximately 1/2" sticking above the jaws, and the remainder dangling free with no bends in it. Second - Apply flux around the end of the cable sticking up and slip on the ferrule (tapered end down, set screw end up). Third - Cut a small length of solder 1/8"=5/32" long and drop into the ferrule, Fourth - Apply heat with the propane torch, playing the heat evenly around the ferrule. The flux will melt and clean the surfaces and then the solder will flow down around the cable and inside the ferrule. Allow time for the parts to cool before touching them. Always exercise caution when soldering. The principle is the same when you are attaching the oc4ps prop shaft to the .098 cable, the OC613PS or OC64PKGPS to the .130 cable, or the OC6150PS to the .150 cable

[TheShaughnessy]

I have tried using the method above and I believe I ended up with a cable that will suffice for my needs. I'm not turning high rpm or power greater then 4s.

I removed the outside winding on a .187 flex and then used a stub bored for .130 flex. Placed stub I vice heated until solder melted, insert flex, add solder as needed, remove from vice and roll on piece of granite or glass while applying heat to true it up, chuck it up in a drill and hold a lil piece of sandpaper over the solder till its nice and smooth. I was able to do the same thing with .150 flex.
I have yet to test them in a boat but I wasn't able to break the joint with my drill and its got quite a reduction.
Still a little concerned with lost prop syndrome.

[ray schrauwen]

Thank you!!!

The crucibles work work very well. The pipe cap thing will work pretty well but a graphite crucible for around 10 bucks on eBay keeps the solder nice and clean and heats up within seconds. It's great for tinning wire as well and your not getting any cross contamination from the steel cap. I've had my graphite crucible 10 plus years and it's still like new. Good for melting silver and gold to!