Hi folks.

Getting ready for final assembly of my first kit, a GP .60 Cub. The hardware provided for the kit is steel rods with solder clevises on one end, threaded clevises for the control ends. The rod is too thick I think to make z-bends for attatching to the servos.

I have never soldered before, the instructions say to use acid flux and silver solder. Assuming I do that, any advice for the process of securing the solder clevises? Is this a good setup or would I be better off buying new double threaded control rods? I want to experiment with different techniques, but am afraid it will not be strong enough and I will lose my plane.

Ideas?


Mill

I may not be qualified to respond since I dont consider myself a pro builder, but I have to ask, are you saying the rods are so thick that they wont bend? Or is it that they dont fit in the servo arm holes?
I was once told that if they wont fit, then it is acceptable to heat the end of the control rod, then insert it thru the hole thus melting the plastic and makein a clean, but slightly enlarged hole, allowing a Z-bend to work. I have done this to many aircraft and had good luck without any mishaps.
I am sure that more seasoned flyers will correct me if this is not really the right way to solve this problem, but like I said, it has worked fine up to this point.

Rods pretty large, I doubt I could enlarge the servo control horns enough without seriously weakining the plastic. I just find it odd that solder clevises would be bad, but I have never used them or heard of people using them.

Mill

Find a source for a Stay-Brite Silver Solder Kit. Includes a small spool of solder and a squeeze bottle of acid flux. Brighten the rod surface with sand paper, steel wool, or whatever. Support the work so that your clevis is properly aligned with the rod. Add a drop or two of flux to the joint. Apply heat to the joint with a 30 watt or greater soldering iron. You'll hear the flux bubble while it gets up to temp. Touch the joint with the solder and watch the solder wick into the joint - feed enough solder in to get complete coverage. It's fun! Let it cool on its own, no blowing on it. After it has cooled, wash the work with soap and water so that residual flux doesn't cause unsightly corrosion.

This will yield a very strong connection - I can't imagine that a threaded clevis would provide more strength than a properly soldered joint. It also provides a lot of flexability in making up just the length of control rod you need. My own crash testing has shown that you can pull a threaded clevis off of a rod but I have never had a solder joint fail.

Rich

Rich,

thank you, that was what I was looking for, actual directions and experience.

Flux, apply it so it is inside the clevis? Heat thoroughly and the solder will wick in between the rod and the clevis? Any danger in overheating the metal before solder applied? Would rather be safe then sorry.

Also, when get plane trimmed and everything looks good, should I also solder the threaded coupling? Or will loc-tite suffice?

What is a good method of holding the joint in place while soldering? It will be inside the plane at the time.


And, what does the flux actually do?

thanks again,

Mill

you don't need silver solder (although it works great). Just go to Radio Shack, Walmart etc, and get a soldering iron or Gun (Guns heat quicker and work better) A roll of solder, and a can of Flux.

Twist the end of the rod in a piece of sandpaper till it's shiny, then dip it in the flux and insert it into the clevis. Apply heat to the sleeve of the clevis and add solder to the wire. (note: the flux will melt and sizzle before the solder starts to melt) once the rod has reached the right temp, the solder will melt and wick it's way into the sleeve. Let it cool, and you're ready!

Sweet Minnflyer,

I wasnt quite sure about where to heat as well. How do you make all those neat pictures anyway? Every other post it seems you produce a really good example picture.

I am feeling slightly more confident about using the solder clevices, thank you all.


Mill

I agree with just about everything said about soldering above. I use "plumbing solder" (Oatey Brand, from Home Depot. This, along with a large bottle of Stay-Brite soldering flux (8 ounces = lifetime supply) will be fine.

A larger soldering gun will make quicker work of the soldering task, but a smaller iron will do fine too. Just make sure you heat the work, not the solder. Don't just drip molten solder on the joint and expect it to hold. The metal parts have to get hot enough to wick the solder into the joint. When it does, it's amazing how little solder is really necessary to get a strong and tight joint.

The big thing here are the "3 rules of soldering"

1- It has to be clean

2- It has to be clean
and
3- You guessed it, It has to be clean!

Don't solder the threaded end of the wire. The solder clevis at one end will be solidly installed. The adjustable clevis at the other end needs to stay adjustable. Just install a jam nut on the threads, snug it up against the clevis and you will still have adjustability for later in the plane's lifetime.

I'm glad me and RCU can be of some help.

I'm a Graphic Artist by trade. These little illustrations I post here are a breeze to whip up compared to the pictures that I have to create at work! LOL

They give me a chance to do something easy now and then.

I was just going to ask where you come up with these pics MinnFlyer! Geez!