I was given a set of floats from a club member sans gear. I have bent 3/16" rod into the support structure and need to cross brace. I do not have access to a welding machine. I had read you can wrap the joint in copper wire and solder so I tried this but it failed.

First the propane torch oxides the copper quickly and so nothing will stick and the flux burnt quickly adding carbon to the mix so nothing would stick. There is too much mass for a solder gun. Also, should the copper wrap completely cover the steel underneath (so you are only soldering to copper)?

What is the correct procedure (step by step for idiots)?

Leave gaps in the copper. Do not overheat. Just enough to melt solder when you touch it to metal. And do use flux.

Can help to rough up the wire a bit with some sandpaper.

That being said, I have had some good luck with plumber's epoxy, that stuff that somes in rolls. Mix it and roll out thin, less that 1/16. Rough up your wire a bit with sandpaper and wrap loosely with copper. Then wrap your epoxy around and press it in to fit between cracks in your LG wires.

Very strong stuff when it hardens.

Tom

The paste I had was unlabelled but had HCl so I assume it was "acid". The solder just said lead free with no content listed so I do not know if it had silver.

I read some posts suggesting "Oatey Safe Flo Silver Solder with HTC paste" I found the solder but the kit had No.95 tinning flux which seemed better as it has powder metal in it too. Home Depot for $11.94 (even has a brush and sand paper included too).

When I solder copper pipe, the flux is inside the fitting so it does not burn; just heat the outside and melt the flux, and then add solder to joint. In this case, it is all open. Do I heat beside the area or directly to the region to solder?

Seems my technique needs help so comments welcome.

The trick must be the solder and/or the flux. For sure the solder melted at a much lower temperature than what I used before. I was able to indirectly heat the wire, have the flux melt and then boil, then hit it with solder and have everything flow nicely. The flux still did seem to burn but still allowed the solder to flow.

It won't win any beauty contests but seems to be strong.

Use a propane torch- the inexpensive ones found at hardware store. File/ sandpaper the music wire and clean with acetone or lacquer thinner. Wrap with copper wire (I use stuff found at craft stores). Gently heat everything with the outside not inner hottest blue flame. Add some Stay Brite flux from the Stay Brite Silver solder kit. If it just barely sizzles the heating was just right to make the flux 'pentrate'. Now heat the music wire only, not any of the copper wire, and feed the silver solder from the other end opposite the flame. The copper wire will be between the flame and solder. Don't make the wire glow red. When the solder starts to melt it will flow toward the flame with the aid of the flux. It's a practiced art/ skill. If there is too much wire to be soldered then so long as you get the solder to flow from one direction then you can work the other end. This may require you put the solder onto the copper wrap. Don't burn the flux off or burn the copper wire wrapping. Let the solder cool to set up before moving your part that is in a jig. When solder sets up remove part and wash with soap and water to remove the acid flux.

Yes to solder 5/32 or larger piano wire plain 60/40 or rosin core solder is extremely difficult. Its harder to find these days but acid core solder works very well.

Better yet these days, though all my floats I built the old way with wire but these days plain s.o. soft strap aluminum is so much easyier to make and looks so much better. Thats all I use these days for float struts.

John

Look for the Solder made for "METALWORK" on it, You can use that and just use a soldering iron, use your method with the copper wire but get the metal solder and you will get good results and it will be strong also.

Why not use a couple of wheel collars...but the wire in from both sides and tighten the set screw...use at least two collars per support?

Chemie, That's a very good job you did!

If I may suggest: Trim off the wire ends sticking out then tap whatever nub remains down and away by placing the completed joint firmly against a solid object (like a vise, which act's as a "bucking" anvil) as you strike with a hammer. Coat your finished assembly with oil and wipe excess off. These type solder joints tend to rust up over time unless protected.

I know it's after the fact, but something worth mentioning is that both pieces of metal need to be CLEAN!

I clean the entire thing with alcohol and then sand the areas to be soldered

Mike,

Ya got it backwards. You sand first, then drink the alcohol.

I cleaned with alcohol, but it was isopropyl so not much sense in drinking that. Sanded, cleaned, soldered; cleaned in soap and water and used file to trim the copper wire per suggestion above (post pic). I painted the metal but taped over the solder joints just in case they break and need to be re-soldered; would be impossible if painted.

Took the plane with new floats up on Sunday but it was hard to stear without a rudder in the water (I had hoped the plane's rudder would be enough). Spent Monday building the new rudder. All hooked up but with 40 mph winds, might be a while before the final test.

If the flip-side of that finished solder joint looks like the front shown in your photo...That joint "ain't goin' nowhere"!