rcFp

I would like to setup a pull-pull system which includes a steel wire with metal couplers( no eye hook) .
as i understand the steel wire should be inserted into the coupler hole and then soldered.
i have several questions regarding that technique :
a) will it be strong enough to use within a fun fly
b) what type of solder material shold i use
c) is a 20w iron solder will be good enough
d) should i just insert the wire normally into the coupler and then solder
e) should i clean the steel wire with alcohol or something before soldering
f) how can i test the solder strength/quality

sorry for all the questions but this is my first pull-pull setup and i really would like it to hold up

thanks

scale only 4 me

My Feedback: (158)

A) done right yes
B)any solder should work
C)20watts? you might want more heat
D)Yes and no
E)clean the wire with about 150 grit sandpaper, also what I do, is take a small drill bit on a drill motor and insert it into the coupler, moving it in and out as to scratch up the inside of the coupler, exposing the freash metal, the same way you're exposing the freash metal by sanding the wire. Then Very important!! push some Flux into the coupler and dip the wire in the flux also, If you don't use flux the Solder will not Wick into the coupler. When you get the coupler/wire hot enough you'll see the solder being wicked in or pulled it to the coupler. once it stops wicking in you're done. this is the same way your houses copper pipes are put to gether, Done right it won't come loose
F) Let cool and with the wire in a vise and holding the coupler with pliers you shouldn't be able to pull it apart, if you can? go back to "E" and start over

This will take a little practice to get good at.

Woodpile

Another definate DO is tinning the wire before inserting it.

Scale only has it right, the solder will wick in to some very tight places, even against the pull of gravity because capillary action will cause it to follow heat and flux. If you already have solder on the wire when you insert it into the coupler, the solder will also naturally flow into the socket. You also have the reassurance of KNOWING that solder is in there properly.

Clean (sand) and flux the tip of the wire about 1/8" longer than the depth on the coupler. Heat the wire up and watch the solder flow between all the stands. If you put too much on, you might have to sand the excess off to get the end into the socket, but it will go in and as I said, the final solder will flow easily into the socket.

The best solder to use is the acid core stuff from Radio Shack. It has a heat activated acid flux in the solder itself and that will help to clean any nasty stuff that might still be in the socket.

Ed

rcFp

one thing i could not figure out from your answers is how do i have to insert the steel wire into the coupler socket

thanks

scale only 4 me

My Feedback: (158)

all the way in as far as it will go? What do you mean?

Woodpile

Until it bottoms out. Measure it if you have to... Taht's why you tin the wire 1/8" more than the coupler is deep. When there's 1/8" of soldered wire sticking out of the coupler, you're there...

Ed

SAL98

My Feedback: (6)

I bend the tip of the wire the same length as the coupler and then insert into the coupler. let solder run into coupler until it fills up to the tip.
Very strong, I have this on rudder in a 1/4 scale edge.

rcFp

I have been told by one of my club member that i should do a a zig-zag edge out of the steel wire
he says that it would create a stronger solder

zigzag wire :

SAL98

My Feedback: (6)

Yes, Same as the bend if only you can get all of the wire into the coupler.

rcFp

it's seem to work quite well

big max 1935

My Feedback: (9)

Some where back in the dark reaches of my mind,some thing tells me that soldering control cable is not the thing to do. Think that vibration would break them where the solder has wicked up the wire. Full sized A/C cables are swagged on. Think that a threaded rod with a hole cross drilled & the cable looped through it & into a copper or brass sleeve crimped on the wires would be better . Du Bro makes such one, looks like a better deal to me. What do you think?>>>>>>>>>>>>big max 1935>>>>>>>>

TerrellFlyer

solder works but I'm lazy,I'm with big max. I use the Du Bro set up,its quick and easy.