Binding UC legs

[Erfolg]

I am about to solder two undercarriage assemblies. It is something i have not undertaken on a RC model, that I can remember. I do remember soldering FF UC legs as a pre teenager. From memory, not very well.

My first thoughts are to use pretty light gauge copper wire to bind the components together. This is based on the notion, that the wire will heat up easily, and that the multiple strands, will re-enforce the joint adequately.

Then i started to think along the lines, if you use a strand from a single core cable, you probably will only need 3 or 6 turns.

Then I thought, find out what others do, why, what are the disadvantages and advantages?

[ERIC CLAPHAM]

In the June '17 issue of this mag, in Alex Whittaker's Weekenders column, shows how he binds and solders piano wire.

[Nigel R]

I used to use whatever my dad had pulled out of a handy length of multicore mains cable.

More than 3 or 6 turns though. The more the merrier - "together we stand" etc.

Haven't done any for years though.

[TIM Shaw]

I use multiple wraps of thin, tinned copper wire, bought for the purpose from Nexus many years ago.

I think it is much easier to get a good binding with thinner wire, and that should lead to a neater job.

The key is to properly clean your UC wire first, and use a good flux (even spirits of salts if you have access to it), and then apply plenty of heat with a big iron or blow torch.

[Bob Cotsford]

I use strands from 45A cable from redundant storage heater wiring for U/Cs, so it's quite thick! I find using thinner wire for binding can end up looking more untidy and it's harder to keep the windings tight. Of course if you were just binding 2mm pushrod wire thinner stuff would be less bulky. Use plenty of flux and remember that excess solder can be filed off so don't worry too much about making it neat at the first attempt.

[Engine Doctor]

Hi . Soldering u/c is no problem. A bit like riding a bike, you never forget. Once you are happy with the bending tin the areas that make the joint. When cleaning the wire use glass paper as carborundum in Emery cloth or wet and dry paper hinders soldering. Use baker's fluid for a good joint. Once tinned it's easy to solder the bits together prior to binding and final soldering. Single strand copper wire is fine but a sheet of thin brass or copper wrapped tightly around the joint looks much better candidate is very strong using normal multi core solder but dipped in baker's  a fluid .Oh and don't forget, use the biggest soldering iron you can get your hands on. Good luck 

[Nigel R]

"When cleaning the wire use glass paper as carborundum in Emery cloth or wet and dry paper hinders soldering."

Every day's a school day!

I always use steel wool to clean up the wire.

[Peter Miller]

I kep a roll of 26 SWG tinned copper wire in the workshop..

Binding should be really close and at least 1/2" long.

Flood it completely with solder

[Stevo]

I use a heavy soldering iron. Yes emery paper etc.. but it's always cleaned with alcohol before assembly. A jig to hold it together is mandatory; flux it with rosin.. Bind it tightly and trim the wire. Get busy with that heavy duty iron and feed in your solder.

Finish off with an alcohol wash;

[Erfolg]

22 swg, so looking for some wire about 30 thou. Perhaps a little chunkier than the light wire I thought of, yet lighter than the single strand wire i was also thinking of.

It is not the soldering that worries me, it is the appropriate wire. Now that I am trained, i can solder, i can solder bus bars, i can join cable, i can attach electric components, Now that i can really solder. Welding is a problem though, although i have been trained to Mig, Tig, Argon Arc, Hydrogen (atomic), Oxy-acetlyne, hot forge weld, I cannot trust myself to switch on the power supply to anyone of them, in reality, let alone do a decent job.

Now having told you how competent i am at soldering, it will worry me how to do it without setting the house on fire, and I am not joking.

[Erfolg]

Stevo

I cannot find a heavy duty soldering iron, for love, or money.

A big soldering iron is by far my preferred option.

My gas torch is unfortunately a bit of a beast. I am pretty unhappy at present.

[Keith Berriman]

Okay you have blow torch have you any pieces of copper bar around ? Warm up the copper bar held with some form of grips in the blow torch and use as a soldering iron

[Allan Bennett]

This is the iron I use for heavy-duty work such as undercarriages. I use 24g tinned copper wire for binding.

[Andy G.]

I use my paint stripper hot air gun for u/c soldering, works a treat on the high setting!

[Nigel R]

U/C legs don't need a subtle soldering iron.

**LINK**

You could use your gas torch, if you were happy to do so.

I only have a cheap and basic machine mart 100W iron very much like the ebay link, perfectly sufficient for this job.

[Engine Doctor]

Posted by Nigel R on 15/06/2017 14:08:44:

I always use steel wool to clean up the wire.

Steel Wool is OK but tends to polish/burnish the piano wire to a smooth finish whereas glass will roughen the surface and give a stronger joint . My metal work teacher back in the early 60's gave that tip . Another tip he taught us was to dip the cleaned piano wire or any iron steel based item into a solution of Copper Sulphate . This deposits a tiny amount of copper onto the steel and solder will flow very easily over this as it has an affinity to copper. You still need a flux but it flows very easily over the copper covered areas.

[Peter Miller]

Believe it or not I now use a 40 watt Weller soldering iron for joining 8 SWG undercarriage legs and it works well.

I still have my 75 watt Henly Solon Iron bought in about 1954 and it still works well but take ages to heat up.

[Jimbo565]

I use 22swg tinned copper wire and one of these, very precise narrow flame.

[Erfolg]

Where Jim uses a pucker cooks gas torch on his Prosciutto and Creme Brulee, I use a dirty big mixed gas torch used in plumbing. It seems some have finesse others just don't.

I do have a Soldering Gun, perhaps I should have tried that.

In the end, i used wire wool, to remove the oxide film. Frys (passive) flux to protect the cleaned wire. I then attached/fastened a mini vice downstream of the joint to act as a heat sink, a cardboard (dampened) baffle to protect from indirect flame spread. For wiping the joint I used a polishing cloth, smeared with flux, as I do not have a mole skin (if that what they really were).

I did find some 30 thou (Cu) wire, which I cleaned and protected etc.

Assembled the lot bound and soldered using the gas torch, with heat sink and baffles, heating carefully, or just a waft of flame, until the solder just flowed into the joint.

It was a lot of messing, took over 2-3 hours, i will need a better method, in future. I will try my solder gun on some scrap stuff, to see if that is good enough, if not I will look for a 100w soldering iron again.

[onetenor]

I use enamelled copper wire about as thin as a hair. Wipe off the enamel ( lacquer /french polish ) with meths. Give it a soak first then wipe along the length with a cloth. I prefer linen or cotton. also wash the U/C wire with meths too. Bind as neatly as you can and whip finish Flux of your choice .I use either an electric heat -gun or a mini blow ,-torch. E bay, Gear Best Amazon ,and Bang Good are sources for the mini blow torch.Very neat intense flame. Be aware the heat travels a long way into the air from that tiny intense flame. Someone mentioned copper sulphate solution putting a film of copper on the steel. Good Idea and the solution is in effect almost Killed Spirits but Sulphuric acid......which helps clean the steel too. ( Pickled ) Heat the area of binding and a small area either side offering up the solder until it flows. Hold the heat on until you see the solder sink into the binding.Keep offering the up the solder until it coats the surface ,Just keeping the solder surface smooth and shiny with a little heat .When you have that it's it job jobbed..

P.S. the mini blow torch I mean are smaller and crayon shaped. Smaller and neater than the cooks torches. Good luck

John

[Allan Bennett]

I find a solder gun not very good for heavy work, for it lacks the hefty copper tip which is the key to retaining heat in the work area.

[Steve Hargreaves - Moderator]

The danger with using a blowtorch is that it is very easy to overheat the U/C wire & cause it to loose it's temper & thus it's springyness......(is that a word??). It can be done but be careful....you may find you have a nicely soldered U/C that bends out of shape & stays there....

A heavy duty soldering iron with a large bit is much easier to control...

[Mike T]

80W Weller 'stained glass' iron, 26swg tinned Cu wire from Maplin, Fry's flux paste. Sorted...

When I was in my early teens, an uncle gave me a small bottle of 'Killed Spirits', liberated from RN stores.  Brushing a little of this on a joint worked wonders!

 

Edited By Mike T on 16/06/2017 23:27:48

[Peter Miller]

I think that "Killed Spirits" is Muriatic Acid. Very similar in effect to Bakers Fluid which is great stuff.but do wash the joint afterwards.

[onetenor]

Killed spirits is if I recall Hydrochloric acid which has been killed with zinc strips dissolved in it till all action stops and some strip remains on the bottom