Soldering flex throttle cable end links
 

I needed to use a flex cable for my thottle and purchased a kit from LHS and have been having problems getting a good solder joint. Note; I am very experienced in soldering electronics, but this is being more difficult than what I anticipated. The instructions do not go into detail about the technique used, but I sand papered the cable and the connector, held together, heated both until solder melted, however I could not get the solder to wick into the cable and connecter to my satisfaction. I eventually kept at it until it looks fair and I am not able to pull the connector off, however I am still not 100 percent sure that its a goodconnection. I tried using a small torch, but that didn't work. I am guessing that the cable is possibly stainless or coated strands, its silver, and the connector is of course brass. Now I am wondering if they expected it to be silver soldered?</p>

RE: Soldering flex throttle cable end links
 

Did you dip the cable in soldering paste first?

RE: Soldering flex throttle cable end links
 

This is always a pain. Don't feel you're the only one. After sanding you have to clean the cable with acetone, MEK, alcohol, etc. Then as Minnflyer said, you have to use solder flux paste on the cable. This allows the heat to transfer though the cable. Ihave found that the cable does not heat well inside the brass sleeve. I heat the cable and apply the solder to the cable outside the sleeve. Then I heat the sleeve and cable together until the solder melts and the cable slides into the sleeve. I always use a torch, but it is easy to get the parts TOO hot. Justa little torch heat is enough. Let it cool and it should be good to go.

pmw

RE: Soldering flex throttle cable end links
 

I just dip the cable in flux (Paste) insert it into the sleeve, lay it on a piece of wood and hold a soldering GUN to the sleeve.

Add the solder right to the opening where the cable enters the sleeve and once it is hot enough, the solder will just wick right in.

RE: Soldering flex throttle cable end links
 

What Minniflyer says, it works for me.  I do use a 100 watt gun and/or a 60 watt chisle tip iron.

RE: Soldering flex throttle cable end links
 

I know there are going to be those that will "yell" about this idea, but it has worked for me. To begin with, I had a throttle servo clevis that needed to be soldered to a braided cable, but obviously heat that close inside the plane and near the plastic cable guide was a no-no. I roughed the inside of the clevis, cleaned the clevis and cable with acetone. Then I filled the clevis(just where the braided cable goes) and coated the braided cable end with JB weld. The next morning it was a perfect bond. On another airplane that I was having the same problem that you are having with a #4 sized elevator push rod and a #4 solder link clevis. I had triedsolder gun, torch, flux, you name it and all I had to show were a bunch of burned clevises and solder globs all over the bench and floor. You guessed it. I roughed the end of the music wire and inside the clevis, used JB weld and it is still flying regularly.

I actually think that if done well, the JB weld could be better than solder. Vibrations won't affect the integrity of a JB weld joint as perhaps it would the metal to metal solder joint.

RE: Soldering flex throttle cable end links
 

I wouldn't have any problem using JB weld on a throttle cable.

An elevator?... If it were an emergency, I guess. I have no doubts it would hold up. It just doesn't give me any "warm and fuzzies"

RE: Soldering flex throttle cable end links
 

I have used the JB trick too.  If I am not able to solider it, I use a cable crimp tool on it.  I had a piece of cable I could not solider.  I tried (4) different soldier and flux combos and they would not stick to the cable.  I ended up just crimping it.  I use a pair of these to crimp the lugs for my pull-pull rudders.

http://www.kleintools.com/onlinecata...dex-TOOLS.html


Dru.

RE: Soldering flex throttle cable end links
 

being a master plumber probably helps but i've never had an issue soldering flex cables.  most likely if the flux isn't working you've used too much heat.  also try warming the cable and then dipping it into the flux.

RE: Soldering flex throttle cable end links
 

http://www3.towerhobbies.com/cgi-bin...XFS75&amp;P=ML

This has always worked for me.  I use it with a butane pencil torch.  It also works good on the other end to keep it from fraying.

RE: Soldering flex throttle cable end links
 

One big problem with silver bearing solders.  Unless you thoroughly clean off the flux (all silver bearing solders I've seen use and acid flux) the items soldered will soon show extreme amounts of corrosion.  Plain old electronic PB solder  and rosen flux will be more than strong enough for soldering clevises and couplers.

RE: Soldering flex throttle cable end links
 

I have never felt a need to use a flex-steel cable for the throttle. A Nyrod does fine for me, or a 2-56 steel rod with a nylon clevis at the throttle and a Z-bend at the servo. Just what does a flex-steel cable add?

RE: Soldering flex throttle cable end links
 

Winglift: Over the years I have had similar problems when using rosin core solder. Finally went to alphametals liquidsolder flux- without strong corrosive residues from ACE Hardware. Wash off the joint with soap when finished. So far over time, none of my soldering has turned green, etc. I not only use the cable system for the throttle, but also for thenose steering, In both cases, I have notexperienced problems except when making anose wheel landing instead of on the main wheels. The reason I use the cable systemsis forless friction from routing the house in other than a straight line. Believe it was reading Harry Higley's books that suggested the cable drive systemsinstead of the solid rods, or Nyrods. I guess it just comes up to what worksthe best for each builder. I do use Nyrods for all other controls.

Rich S.
A&amp; P Mech

RE: Soldering flex throttle cable end links
 

The type of flux found in electronic solders does not work well for me when soldering those Dubro throttle cables.  I think that brass fitting and stainless steel cable (?) require a more aggressive flux.  Plumber's paste works well in my experience.  Just clean it off well with alcohol while the joint is still warm. 

A metallurgist at work once told me that brass requires a special flux.  I have soldered brass using plain old Kester 44, but the brass had to be freshly cleaned.  I guess brass must form a surface oxide or corrosion product quickly, and that layer is a problem for normal electronic grade fluxes.

RE: Soldering flex throttle cable end links
 

I did not dip it in flux or clean it with acetone prior to soldering.http://www.rcuniverse.com/forum/js/f...ssed_smile.gif I was using Kester 44. This has been educational. Will try again after making a trip to the hardware store and will let you know the outcome.

RE: Soldering flex throttle cable end links
 

I wish that I could illustrate like MinnFlyer, but in this case I had asomewhat moderatebend between the throttle servo and the throttle. With Nyrod there was a lot of flex and in this case bowing of the yellow inner Nyrod from the exit of the outer sheath to the throttle arm and likewise to the servo arm especially when reaching the limits of the throttle ie fully closed or fully open. I tried a solid rod, but...............this is starting to sound like the three bears.............it was too stiff for thebend and would cause binding and I finally gave up on that after many adjustments etc. The flex cable was the ideal compromise..........and was just right............, but after many attempts could not get a good solder joint. I was kind of glad to know that I was not the only one who was or had problems.

RE: Soldering flex throttle cable end links
 

Well, this has been a journey. After a few attempts, I have a good solder joint. I went to Ace HW and purchased the liquid flux that Aerorich mentioned and I noticed at Specialty Soldering Kit that included a silver solder wire and special flux which mentioned that it was good for soldering nickel alloys and copper. Since the flex cable may have some nickel in it and the brass fitting of course has copper it seemed like a good choice. It has 98% tin and 2% silver. It worked.http://www.rcuniverse.com/forum/js/f.../thumbs_up.gif Did use a torch instead of the Weller. I could not get it to heat up enough using the Weller. Thanks all.

RE: Soldering flex throttle cable end links
 

<span style="FONT-SIZE: 12pt; FONT-FAMILY: "Times New Roman"; mso-fareast-font-family: "Times New Roman"; mso-ansi-language: EN-US; mso-fareast-language: EN-US; mso-bidi-language: AR-SA">One thing that works well for me besides flux past is I lightly tin the cable slide it in the fitting then heat the brass fitting. Then touch the joint with the solder <span style="mso-spacerun: yes"> </span><span style="mso-spacerun: yes"> </span></span>

RE: Soldering flex throttle cable end links
 

Thanks PA-18cub150. That was one of the first things I tried, which is a basic soldering technique. As it turns out, my vast electronic soldering techniques didn't work and I my next thought was to buy some flux and see if that worked which was suggested to me in this forum. I spent several hours trying to get a good solder joint. Even though the joint appeared strong, tested by pulling on the ends, it just didn't look right and in my opinion could have failed over time. That's when I threw up my hands and brought it to the experts here. I think all suggestions were good, with possibly the exception of using JB Weld, for me, I just wouldn't trust it.