Soldering flex cable

[Lockk]

So I went to solder my flex cable (the first 1/4 to 1/2 that goes in the collet).


First heated and fluxed the cable to get the grease off
polish with emery cloth then electric de-greaser
Flux again, then first attempt using Novak 3% silver solder and soldering iron... solder melts but balls up and falls off

second attempt clean polish, etc, this time I try using real silver solder and paste ultraflux thats designed for silver solder about the same thing
happened except I got some areas that the silver solder stuck. Well as I ground some of the silver solder smooth the cable unwound maybe it got to
hot?

Well new flex cable on the way.

I could use a suggestion or two.

Thanks

[NitroVal]

Not sure with flex cable, but with wire, if the solder balls up and runs off, the wire isnt hot enough to fuse with the solder.

[Stinger9D9]

Yeah, it sounds like the cable isn't hot enough for the solder to flow onto it. You have to get the cable pretty hot, pretty quickly too. I don't think an iron will cut it - it will heat up the cable slowly, and the heat will keep conducting down the cable until the whole cable warms up, but the end you need to solder never really reaches the necessary temperature. A soldering gun will probably work, when I re-soldered my Motley Crew cable, I didn't have the patience for a soldering gun either.

I used a propane torch (and a lot of care - you can make the cable too hot and it will become brittle if you do it wrong). The torch heated the end of the cable and stub shaft up FAST. I didn't keep the torch on it for long at all.

It really takes some practice.

I also have a couple cables I put together with the Loctite sleeve retaining compound Steve sells here on OSE. Never had a problem with any of them. I would have used retaining compound on the MC cable if it didn't already have solder on it.

Check out this article - it worked great for me on my SV:

http://www.offshoreelectrics.com/inf...mble-shaft.php

[siberianhusky]

Try a butane micro torch, plenty of easily controllable heat for a flex cable that size. Sounds like not enough heat as your prep was well done and you used the proper materials. Personally I really only worry about the very tip of the cable, just enough to keep it from unwinding, I figure that this keeps the heat as close to the end of the cable as possible, hoping to keep any weakness caused by heating inside the coupler. The small pencil tip flame of the micro torch really helps in doing this.
I've done it many times with a propane torch but find it kinda like taking a sledge hammer to a finishing nail, it's easy to overheat the cable pretty quickly.

[Lockk]

Thanks everyone for the tips I went back and practiced and one I did overheat the cable and it got brittle the other thing I sort of forgot was just
as the ultra flux turns glassy is about when you can add the solder. I also changed to a MAPP gas torch I have and that gave me plenty of heat almost
to much I like the micro butane idea and keeping the solder at the very end.

Thanks again much appreciated.

[tanasit]

Forget about soldering, go for what Steve suggested as the above link indicates...
I did at least 10 of those without any problems. At one point one of which was too short because of my modifications, I heated the drive shaft for only a few seconds and the cable just poped right off!. After a good clean up, with new cable but still the old drive shaft, same loctite 603 procedure, waited overnight and it works fine.

[Lockk]

Forget about soldering, go for what Steve suggested as the above link indicates...
I did at least 10 of those without any problems. At one point one of which was too short because of my modifications, I heated the drive shaft for only a few seconds and the cable just poped right off!. After a good clean up, with new cable but still the old drive shaft, same loctite 603 procedure, waited overnight and it works fine.

I should clarify a bit this is for a twin Cat with flex cable drives I'm just doing the ends so it doesn't unwind at the collet my other end is square drive that's a slip fit into the stinger. Loctite in open air on the wire probably not going to work.

[Stinger9D9]

I should clarify a bit this is for a twin Cat with flex cable drives I'm just doing the ends so it doesn't unwind at the collet my other end is square drive that's a slip fit into the stinger. Loctite in open air on the wire probably not going to work.

In that case, no the Loctite won't work out in open air, only where you insert it into the stub shaft.

Forget what I said about soldering, I just proved how bad I am at soldering to myself earlier tonight when I lost the stub shaft (and drive dog, nut and 40/52x3 prop) off the end of my MC flex shaft at the pond.

That @#$% shaft worked fine for 7 runs and then let go on the 8th run. You'd think it would have failed on the first run, not the 8th, but it just goes to show, you can never be sure.

[FE_Chris]

For what it's worth, in the past I always used the loctite stuff and I have never had a flex shaft come apart. Soldering always look like a PITA.

[longballlumber]

Guys...

http://en.wikipedia.org/wiki/Soldering

http://en.wikipedia.org/wiki/Brazing

I see many questions about flex shafts and how to join with a stub shaft. PLEASE do yourselves a favor and read up on the difference between soldering and brazing. Don’t try and solder when you should be brazing… You really need a good quality (high silver content) to get the strength needed with today’s high power/torque brushless motors. This is one place that I would suggest paying the piper for his services…. Buy a cable from a reputable manufacture, I prefer Hughey cables. BEST in the business!

Later,
Mike

[sailr]

stay with the loctite for flex to stub shaft. I have NEVER had one come apart. Just be sure to let it dry for at least a full day. I usually let mine sit for two or three. I also put the stub shaft lightly in a vise and let the flexshaft stick up. That way none of the loctite can run out.

Soldering the other end is a real PITA. I've used every kind of solder. I found that when it balls up on the shaft, I have a rag handy and quickly swipe it down into the flex. I can then reheat it and it will flow around the cable.

[siberianhusky]

Try Sta-Brite with the supplied flux, always seems to work, depending you may have to get it from a welding shop.

[sailr]

I haven't had any better luck with sta-brite either. I do use a silver solder very similar with the acid flux. I don't remember the brand but it works better than sta-brite. And yes, I do use a torch.

[ray schrauwen]

If you get it too hot the solder will not stick either, the flux burns off.

Soldering or brazing is sort of an art that i leave to Ed Hughey & other pro's.

If I solder the end to go into a collet, I use stay-bright and an 80 watt Orange Weller Iron. Works perfectly.

I have also used loctite for stub shafts and it works Fantabulously, lol... I have even used Hobby King Loctite TL-680 and it is rock solid too!!

[martin]

Soft solder or silver solder or electrical solder what ever you want to call it is a waste of time on the ends of flexes, It still comes unravelled after time sometimes pretty quickly even if you have gotten it to take ok. I spoke to Doug Smock about this very thing recently & he brazes ( silver solder ) just the very tip of the flex. You have to watch the temp & heat just the tip of the flex but theirs no problem with it taking providing you have prepped right & it deff dosnt come unravelled at all. Its literally just the tip that gets done. Martin.