Binding undercarriage using solder and wire

[martin collins 1]

I n my 1/4 scale Cassutt build i have this job to do today, having not done it before i gather i clean the wire (i will use petrol), i have some proper solder not the 3 core stuff and wrap wire round the legs, add some flux and solder using one of those pencil gas flame jobbies. Does that sound correct, also the model instructions call for 30 amp fuse wire, i have only 5 amp here or some much thicker 20 ga craft wire `borrowed` from the wife, will this work? If not can i use some car or house copper wire stripped back to save myself a time consuming trip to Screwfix for the fuse wire. I am on the last day of a 7 day build challenge and time is ticking away fast, don`t really want to lose 30 mins going out!

[Piers Bowlan]

Personally I would use wire wool and meths for cleaning not petrol. I never have tried it but the stripped out single strand mains copper wire would get my vote. Not too sure about the craft wire, it depends what it is made from/coated with? You could try a test piece and see how it goes.

A quarter scale cassutt in a week is pretty good going to say the least! 

Edited By Piers Bowlan on 09/05/2020 09:02:22

[Ray Wood 4]

Hi Martin,

I'd be careful not to let the piano wire get too hot, it may lose it's tempering ?I

Regards Ray

Edited By Ray Wood 4 on 09/05/2020 09:16:27

[DaveyP]

Stripped out mains wire works well, and gets my vote too

[Andy Stephenson]

Like Ray says I wouldn't use a flame either. It will soften the wire if it cools slowly or it could become glass hard and brittle if it cools too quickly. Either way it will loose all it's "spring" and be useless as an undercarriage.The springiness is set in the manufacturing process by precision heat treatment. Using an iron won't heat the it beyond the temperature where it will affect the hardness so this is the recommended way of soldering piano wire.

A.

[martin collins 1]

Here`s what i have as a soldering iron, unfortunately the wattage has worn off it, does it loom man enough for those wires?

[Wingman]

That looks like quite a meaty soldering iron so I reckon it would be worth a go with it - probably have to hold it on for a while until the heat builds up on the joint then just track down the wire with the iron adding solder as you go. If you have to use blow lamp or similar, heat the wire a bit, remove the flame and dab the solder on and keep doing that in small steps until the solder flows - melting the solder with the flame just makes a mess and the joint will probably just come undone when it's in use - i.e. the first landing. Just make sure the binding wire is also clean (steel wool or emery cloth) before soldering.

[Peter Miller]

I use a Weller 40 Watt iron, it happily solders two pieces of 8SWG together when bound. That iron looks to be about 40Watt with the 1/4" bit.

I would prefer thicker binding wire. I keep a roll of 26SWG tinned copper wire that job, A piece of telephone wire will provide a suitable wire if you can find some.

if using The car or household wire it would need quite a lot of wire.

[Ray Wood 4]

Hello Martin,

This is my collection of soldering irons old school technology, but worth their weight in gold 😃

240 , 150 & 25 watts

Regards Ray

[Ray Wood 4]

Hello Martin,

This is my collection of soldering irons old school technology, but worth their weight in gold 😃

240 , 150 & 25 watts

Regards Ray

Oooops !!!!

 

Edited By Ray Wood 4 on 09/05/2020 11:52:44

[Martin Harris - Moderator]

Wingman's point is, in my opinion, the key [apart from scrupulous cleaning] to successful soldering. Whether soldering electrical components, structural points or tinwork, the only time you should touch solder to the iron is to tin the tip. The wires or parts being soldered must be hot enough to melt the solder when it is touched to the metal being soldered. Fresh tinning aids heat transfer to the components being soldered.

I picked up an old fashioned "lump of copper on a stick" soldering iron which is useful for heavy jobs but although many will say they can't cope without a large heat retaining capacity, my 50 year old Weller instant heat gun copes with surprisingly large joints.

Edited By Martin Harris on 09/05/2020 12:02:26

[Paul Marsh]

I use de-soldering braid for joining. Used it before and found that it works. Just did it on a Panic build a few days ago.

[Piers Bowlan]

I used to have one of those 'gas flame jobbies' as you put it but I never had much success using it for soldering. It may have been too hot or I wondered if the combustion was coating the work-piece with impurities making the solder reluctant to flow? A soldering iron seems more controllable somehow.

[Engine Doctor]

The main requirements for a strong joint hen making undercarriages are clean wire including the binding wire, enough heat for the job , a good aggressive flux .

Cleaning , as already said earlier use wire wool or glass paper. Don't use emery cloth ,wet and dry as they contaminate the surface of the wire. Make sure the binding wire is also cleaned before binding the joint. Tin the parts before assembly as this will make final assembly much quicker and stronger. Tack the joint with solder before binding and aligning can help .

Instead of using copper wire for binding a strip of tin plate can be used . This takes solder very well and makes a very neat strong joint on u/c joints.

A large enough soldering iron that can quickly supply the needed heat to the job. Using a flame can cause damage to the wire and overheat the job unless very experienced.

Flux. A good aggressive flux like Bakers Fluid is a great help . Don't use it on anything electrical or sensitive and wash parts in soapy water when job is complete. Flux cored solder can be used but make sure all parts are properly tinned before assembly.

Finally a simple jig that holds the u/c in position while soldering will help enormously.

Good luck let us know how you get on.

[Former Member]

[This posting has been removed]

[Engine Doctor]

Posted by Doc Marten on 09/05/2020 12:35:37:

Bakers flux is great for this job, I read an article by the late, great Brian Winch on making "Killed Spirit" which is very similar to Bakers apparently?

Hi Doc I believe the Baker fluid is the same as " Killed Spirit"

Just looked on ebay and wow has it rocketed in price !! A tiny bottle anything from £13 to £25 !! should be re-named Bakers Gold

[Peter Miller]

I seem to remember in my youth that another good cleaner was muriatic acid but that was back in the fifties in the Argentine

And,in passing, I still have my Henley SOlon 75 Watt iron bought in the mid 50s anstill working well but it oes take a long time to heat up

Edited By Peter Miller on 09/05/2020 13:30:51

[Steven S]

I've used muriatic acid, but only on galvanized sheet metal.like my downspouts.

[Former Member]

[This posting has been removed]

[FlyinBrian]

I have never used bakers fluid but I have used a paste flux but normally I just ensure everything is clean, abrade the piano wire with fine sandpaper where you need to solder then wipe over with meths to ensure there is no grease left. Tin the area using resin core solder, wipe of any excess tinning so that the two parts lie close together then using clothes pegs or similar hold them together while you tack solder the two parts together. I use tinned copper wire recovered from 4 core telephone cable to bind the parts together, 3/4" inch of binding is normally enough. Then ensuring the parts can not move run more solder along and into the joint. Use the solder sparingly too much is not better - just make sure the binding wire is completely wetted with solder.

I have undercarts that are 10+ years old and are still fine.

[Dad_flyer]

I use my plumbing flux paste (La Co). It works well on many materials. As said above, effective fluxes are corrosive and need cleaning if afterwards.

[Andy Stephenson]

Rather than using acid flux for difficult joints, I use this...

It's sold as plumbers flux but it's good for making any type of soldered joint and it doesn't seem to be corrosive. It comes in paste form so it's easy to apply.

A.

PS Dad Flyer, you beat me to it.

Edited By Andy Stephenson on 09/05/2020 15:51:03

Edited By Andy Stephenson on 09/05/2020 15:51:29

[Stuart C]

Many years ago, I was struggling to solder up a speed model dolly, when my father said "Try this.", whereupon he produced a jam jar containing what I can best describe as a heavy, battleship grey sludge. After a good stir, the sludge was painted over all the bindings and the soldering iron applied. The sludge would then separate into bright solder with a dark brown sort of flux. I can still remember the distinctive sweet smell of the fumes. Every joint was perfect with no blobs nor breaks. I found it to also be brilliant for fuel tank seam joints. Now, I have never found out what it was called, and neither have I come across anybody else that has used it. Can anyone here cast some light on this magic material? (We are taking of 1950's era).

Edited By Stuart C on 09/05/2020 17:04:38

[Denis Watkins]

Posted by Stuart C on 09/05/2020 17:02:30:

Many years ago, I was struggling to solder up a speed model dolly, when my father said "Try this.", whereupon he produced a jam jar containing what I can best describe as a heavy, battleship grey sludge. After a good stir, the sludge was painted over all the bindings and the soldering iron applied. The sludge would then separate into bright solder with a dark brown sort of flux. I can still remember the distinctive sweet smell of the fumes. Every joint was perfect with no blobs nor breaks. I found it to also be brilliant for fuel tank seam joints. Now, I have never found out what it was called, and neither have I come across anybody else that has used it. Can anyone here cast some light on this magic material? (We are taking of 1950's era).

Edited By Stuart C on 09/05/2020 17:04:38

It is solder paste Stuart, available as Carrs solder paint

Model railway lads use this more than most

[Stuart C]

Well, how about that, then? Thank you Dennis. After all these years, finally the answer.